AWSKMS

The service configuration used to instantiate this service client.

Returns the singleton service client. If the singleton object does not exist, the SDK instantiates the default service client with defaultServiceConfiguration from [AWSServiceManager defaultServiceManager]. The reference to this object is maintained by the SDK, and you do not need to retain it manually.

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
   let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
   let configuration = AWSServiceConfiguration(region: .USEast1, credentialsProvider: credentialProvider)
   AWSServiceManager.default().defaultServiceConfiguration = configuration

   return true

}

Objective-C

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                     identityPoolId:@"YourIdentityPoolId"];
     AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSEast1
                                                                          credentialsProvider:credentialsProvider];
     [AWSServiceManager defaultServiceManager].defaultServiceConfiguration = configuration;

     return YES;
 }

Then call the following to get the default service client:

Swift

let KMS = AWSKMS.default()

Objective-C

AWSKMS *KMS = [AWSKMS defaultKMS];

Creates a service client with the given service configuration and registers it for the key.

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
   let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
   let configuration = AWSServiceConfiguration(region: .USWest2, credentialsProvider: credentialProvider)
   AWSKMS.register(with: configuration!, forKey: "USWest2KMS")

   return true

}

Objective-C

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                    identityPoolId:@"YourIdentityPoolId"];
    AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSWest2
                                                                         credentialsProvider:credentialsProvider];

    [AWSKMS registerKMSWithConfiguration:configuration forKey:@"USWest2KMS"];

    return YES;
}

Then call the following to get the service client:

Swift

let KMS = AWSKMS(forKey: "USWest2KMS")

Objective-C

AWSKMS *KMS = [AWSKMS KMSForKey:@"USWest2KMS"];

Retrieves the service client associated with the key. You need to call + registerKMSWithConfiguration:forKey: before invoking this method.

For example, set the default service configuration in - application:didFinishLaunchingWithOptions:

Swift

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
   let credentialProvider = AWSCognitoCredentialsProvider(regionType: .USEast1, identityPoolId: "YourIdentityPoolId")
   let configuration = AWSServiceConfiguration(region: .USWest2, credentialsProvider: credentialProvider)
   AWSKMS.register(with: configuration!, forKey: "USWest2KMS")

   return true

}

Objective-C

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    AWSCognitoCredentialsProvider *credentialsProvider = [[AWSCognitoCredentialsProvider alloc] initWithRegionType:AWSRegionUSEast1
                                                                                                    identityPoolId:@"YourIdentityPoolId"];
    AWSServiceConfiguration *configuration = [[AWSServiceConfiguration alloc] initWithRegion:AWSRegionUSWest2
                                                                         credentialsProvider:credentialsProvider];

    [AWSKMS registerKMSWithConfiguration:configuration forKey:@"USWest2KMS"];

    return YES;
}

Then call the following to get the service client:

Swift

let KMS = AWSKMS(forKey: "USWest2KMS")

Objective-C

AWSKMS *KMS = [AWSKMS KMSForKey:@"USWest2KMS"];

Removes the service client associated with the key and release it.

Cancels the deletion of a KMS key. When this operation succeeds, the key state of the KMS key is Disabled. To enable the KMS key, use EnableKey.

For more information about scheduling and canceling deletion of a KMS key, see Deleting KMS keys in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:CancelKeyDeletion (key policy)

Related operations: ScheduleKeyDeletion

Cancels the deletion of a KMS key. When this operation succeeds, the key state of the KMS key is Disabled. To enable the KMS key, use EnableKey.

For more information about scheduling and canceling deletion of a KMS key, see Deleting KMS keys in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:CancelKeyDeletion (key policy)

Related operations: ScheduleKeyDeletion

Connects or reconnects a custom key store to its backing key store. For an CloudHSM key store, ConnectCustomKeyStore connects the key store to its associated CloudHSM cluster. For an external key store, ConnectCustomKeyStore connects the key store to the external key store proxy that communicates with your external key manager.

The custom key store must be connected before you can create KMS keys in the key store or use the KMS keys it contains. You can disconnect and reconnect a custom key store at any time.

The connection process for a custom key store can take an extended amount of time to complete. This operation starts the connection process, but it does not wait for it to complete. When it succeeds, this operation quickly returns an HTTP 200 response and a JSON object with no properties. However, this response does not indicate that the custom key store is connected. To get the connection state of the custom key store, use the DescribeCustomKeyStores operation.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

The ConnectCustomKeyStore operation might fail for various reasons. To find the reason, use the DescribeCustomKeyStores operation and see the ConnectionErrorCode in the response. For help interpreting the ConnectionErrorCode, see CustomKeyStoresListEntry.

To fix the failure, use the DisconnectCustomKeyStore operation to disconnect the custom key store, correct the error, use the UpdateCustomKeyStore operation if necessary, and then use ConnectCustomKeyStore again.

CloudHSM key store

During the connection process for an CloudHSM key store, KMS finds the CloudHSM cluster that is associated with the custom key store, creates the connection infrastructure, connects to the cluster, logs into the CloudHSM client as the kmsuser CU, and rotates its password.

To connect an CloudHSM key store, its associated CloudHSM cluster must have at least one active HSM. To get the number of active HSMs in a cluster, use the DescribeClusters operation. To add HSMs to the cluster, use the CreateHsm operation. Also, the kmsuser crypto user (CU) must not be logged into the cluster. This prevents KMS from using this account to log in.

If you are having trouble connecting or disconnecting a CloudHSM key store, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.

External key store

When you connect an external key store that uses public endpoint connectivity, KMS tests its ability to communicate with your external key manager by sending a request via the external key store proxy.

When you connect to an external key store that uses VPC endpoint service connectivity, KMS establishes the networking elements that it needs to communicate with your external key manager via the external key store proxy. This includes creating an interface endpoint to the VPC endpoint service and a private hosted zone for traffic between KMS and the VPC endpoint service.

To connect an external key store, KMS must be able to connect to the external key store proxy, the external key store proxy must be able to communicate with your external key manager, and the external key manager must be available for cryptographic operations.

If you are having trouble connecting or disconnecting an external key store, see Troubleshooting an external key store in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:ConnectCustomKeyStore (IAM policy)

Related operations

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Connects or reconnects a custom key store to its backing key store. For an CloudHSM key store, ConnectCustomKeyStore connects the key store to its associated CloudHSM cluster. For an external key store, ConnectCustomKeyStore connects the key store to the external key store proxy that communicates with your external key manager.

The custom key store must be connected before you can create KMS keys in the key store or use the KMS keys it contains. You can disconnect and reconnect a custom key store at any time.

The connection process for a custom key store can take an extended amount of time to complete. This operation starts the connection process, but it does not wait for it to complete. When it succeeds, this operation quickly returns an HTTP 200 response and a JSON object with no properties. However, this response does not indicate that the custom key store is connected. To get the connection state of the custom key store, use the DescribeCustomKeyStores operation.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

The ConnectCustomKeyStore operation might fail for various reasons. To find the reason, use the DescribeCustomKeyStores operation and see the ConnectionErrorCode in the response. For help interpreting the ConnectionErrorCode, see CustomKeyStoresListEntry.

To fix the failure, use the DisconnectCustomKeyStore operation to disconnect the custom key store, correct the error, use the UpdateCustomKeyStore operation if necessary, and then use ConnectCustomKeyStore again.

CloudHSM key store

During the connection process for an CloudHSM key store, KMS finds the CloudHSM cluster that is associated with the custom key store, creates the connection infrastructure, connects to the cluster, logs into the CloudHSM client as the kmsuser CU, and rotates its password.

To connect an CloudHSM key store, its associated CloudHSM cluster must have at least one active HSM. To get the number of active HSMs in a cluster, use the DescribeClusters operation. To add HSMs to the cluster, use the CreateHsm operation. Also, the kmsuser crypto user (CU) must not be logged into the cluster. This prevents KMS from using this account to log in.

If you are having trouble connecting or disconnecting a CloudHSM key store, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.

External key store

When you connect an external key store that uses public endpoint connectivity, KMS tests its ability to communicate with your external key manager by sending a request via the external key store proxy.

When you connect to an external key store that uses VPC endpoint service connectivity, KMS establishes the networking elements that it needs to communicate with your external key manager via the external key store proxy. This includes creating an interface endpoint to the VPC endpoint service and a private hosted zone for traffic between KMS and the VPC endpoint service.

To connect an external key store, KMS must be able to connect to the external key store proxy, the external key store proxy must be able to communicate with your external key manager, and the external key manager must be available for cryptographic operations.

If you are having trouble connecting or disconnecting an external key store, see Troubleshooting an external key store in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:ConnectCustomKeyStore (IAM policy)

Related operations

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Creates a friendly name for a KMS key.

You can use an alias to identify a KMS key in the KMS console, in the DescribeKey operation and in cryptographic operations, such as Encrypt and GenerateDataKey. You can also change the KMS key that’s associated with the alias (UpdateAlias) or delete the alias (DeleteAlias) at any time. These operations don’t affect the underlying KMS key.

You can associate the alias with any customer managed key in the same Amazon Web Services Region. Each alias is associated with only one KMS key at a time, but a KMS key can have multiple aliases. A valid KMS key is required. You can’t create an alias without a KMS key.

The alias must be unique in the account and Region, but you can have aliases with the same name in different Regions. For detailed information about aliases, see Using aliases in the Key Management Service Developer Guide.

This operation does not return a response. To get the alias that you created, use the ListAliases operation.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.

Required permissions

• kms:CreateAlias on the alias (IAM policy).

• kms:CreateAlias on the KMS key (key policy).

For details, see Controlling access to aliases in the Key Management Service Developer Guide.

Related operations:

• DeleteAlias

• ListAliases

• UpdateAlias

Creates a friendly name for a KMS key.

You can use an alias to identify a KMS key in the KMS console, in the DescribeKey operation and in cryptographic operations, such as Encrypt and GenerateDataKey. You can also change the KMS key that’s associated with the alias (UpdateAlias) or delete the alias (DeleteAlias) at any time. These operations don’t affect the underlying KMS key.

You can associate the alias with any customer managed key in the same Amazon Web Services Region. Each alias is associated with only one KMS key at a time, but a KMS key can have multiple aliases. A valid KMS key is required. You can’t create an alias without a KMS key.

The alias must be unique in the account and Region, but you can have aliases with the same name in different Regions. For detailed information about aliases, see Using aliases in the Key Management Service Developer Guide.

This operation does not return a response. To get the alias that you created, use the ListAliases operation.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.

Required permissions

• kms:CreateAlias on the alias (IAM policy).

• kms:CreateAlias on the KMS key (key policy).

For details, see Controlling access to aliases in the Key Management Service Developer Guide.

Related operations:

• DeleteAlias

• ListAliases

• UpdateAlias

Creates a custom key store backed by a key store that you own and manage. When you use a KMS key in a custom key store for a cryptographic operation, the cryptographic operation is actually performed in your key store using your keys. KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key store proxy and external key manager outside of Amazon Web Services.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

Before you create the custom key store, the required elements must be in place and operational. We recommend that you use the test tools that KMS provides to verify the configuration your external key store proxy. For details about the required elements and verification tests, see Assemble the prerequisites (for CloudHSM key stores) or Assemble the prerequisites (for external key stores) in the Key Management Service Developer Guide.

To create a custom key store, use the following parameters.

• To create an CloudHSM key store, specify the CustomKeyStoreName, CloudHsmClusterId, KeyStorePassword, and TrustAnchorCertificate. The CustomKeyStoreType parameter is optional for CloudHSM key stores. If you include it, set it to the default value, AWS_CLOUDHSM. For help with failures, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.

• To create an external key store, specify the CustomKeyStoreName and a CustomKeyStoreType of EXTERNAL_KEY_STORE. Also, specify values for XksProxyConnectivity, XksProxyAuthenticationCredential, XksProxyUriEndpoint, and XksProxyUriPath. If your XksProxyConnectivity value is VPC_ENDPOINT_SERVICE, specify the XksProxyVpcEndpointServiceName parameter. For help with failures, see Troubleshooting an external key store in the Key Management Service Developer Guide.

When the operation completes successfully, it returns the ID of the new custom key store. Before you can use your new custom key store, you need to use the ConnectCustomKeyStore operation to connect a new CloudHSM key store to its CloudHSM cluster, or to connect a new external key store to the external key store proxy for your external key manager. Even if you are not going to use your custom key store immediately, you might want to connect it to verify that all settings are correct and then disconnect it until you are ready to use it.

For help with failures, see Troubleshooting a custom key store in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:CreateCustomKeyStore (IAM policy).

Related operations:

• ConnectCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Creates a custom key store backed by a key store that you own and manage. When you use a KMS key in a custom key store for a cryptographic operation, the cryptographic operation is actually performed in your key store using your keys. KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key store proxy and external key manager outside of Amazon Web Services.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

Before you create the custom key store, the required elements must be in place and operational. We recommend that you use the test tools that KMS provides to verify the configuration your external key store proxy. For details about the required elements and verification tests, see Assemble the prerequisites (for CloudHSM key stores) or Assemble the prerequisites (for external key stores) in the Key Management Service Developer Guide.

To create a custom key store, use the following parameters.

• To create an CloudHSM key store, specify the CustomKeyStoreName, CloudHsmClusterId, KeyStorePassword, and TrustAnchorCertificate. The CustomKeyStoreType parameter is optional for CloudHSM key stores. If you include it, set it to the default value, AWS_CLOUDHSM. For help with failures, see Troubleshooting an CloudHSM key store in the Key Management Service Developer Guide.

• To create an external key store, specify the CustomKeyStoreName and a CustomKeyStoreType of EXTERNAL_KEY_STORE. Also, specify values for XksProxyConnectivity, XksProxyAuthenticationCredential, XksProxyUriEndpoint, and XksProxyUriPath. If your XksProxyConnectivity value is VPC_ENDPOINT_SERVICE, specify the XksProxyVpcEndpointServiceName parameter. For help with failures, see Troubleshooting an external key store in the Key Management Service Developer Guide.

When the operation completes successfully, it returns the ID of the new custom key store. Before you can use your new custom key store, you need to use the ConnectCustomKeyStore operation to connect a new CloudHSM key store to its CloudHSM cluster, or to connect a new external key store to the external key store proxy for your external key manager. Even if you are not going to use your custom key store immediately, you might want to connect it to verify that all settings are correct and then disconnect it until you are ready to use it.

For help with failures, see Troubleshooting a custom key store in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:CreateCustomKeyStore (IAM policy).

Related operations:

• ConnectCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Adds a grant to a KMS key.

A grant is a policy instrument that allows Amazon Web Services principals to use KMS keys in cryptographic operations. It also can allow them to view a KMS key (DescribeKey) and create and manage grants. When authorizing access to a KMS key, grants are considered along with key policies and IAM policies. Grants are often used for temporary permissions because you can create one, use its permissions, and delete it without changing your key policies or IAM policies.

For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide. For examples of working with grants in several programming languages, see Programming grants.

The CreateGrant operation returns a GrantToken and a GrantId.

• When you create, retire, or revoke a grant, there might be a brief delay, usually less than five minutes, until the grant is available throughout KMS. This state is known as eventual consistency. Once the grant has achieved eventual consistency, the grantee principal can use the permissions in the grant without identifying the grant.

  However, to use the permissions in the grant immediately, use the GrantToken that CreateGrant returns. For details, see Using a grant token in the Key Management Service Developer Guide.

• The CreateGrant operation also returns a GrantId. You can use the GrantId and a key identifier to identify the grant in the RetireGrant and RevokeGrant operations. To find the grant ID, use the ListGrants or ListRetirableGrants operations.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation on a KMS key in a different Amazon Web Services account, specify the key ARN in the value of the KeyId parameter.

Required permissions: kms:CreateGrant (key policy)

Related operations:

• ListGrants

• ListRetirableGrants

• RetireGrant

• RevokeGrant

Adds a grant to a KMS key.

A grant is a policy instrument that allows Amazon Web Services principals to use KMS keys in cryptographic operations. It also can allow them to view a KMS key (DescribeKey) and create and manage grants. When authorizing access to a KMS key, grants are considered along with key policies and IAM policies. Grants are often used for temporary permissions because you can create one, use its permissions, and delete it without changing your key policies or IAM policies.

For detailed information about grants, including grant terminology, see Grants in KMS in the Key Management Service Developer Guide. For examples of working with grants in several programming languages, see Programming grants.

The CreateGrant operation returns a GrantToken and a GrantId.

• When you create, retire, or revoke a grant, there might be a brief delay, usually less than five minutes, until the grant is available throughout KMS. This state is known as eventual consistency. Once the grant has achieved eventual consistency, the grantee principal can use the permissions in the grant without identifying the grant.

  However, to use the permissions in the grant immediately, use the GrantToken that CreateGrant returns. For details, see Using a grant token in the Key Management Service Developer Guide.

• The CreateGrant operation also returns a GrantId. You can use the GrantId and a key identifier to identify the grant in the RetireGrant and RevokeGrant operations. To find the grant ID, use the ListGrants or ListRetirableGrants operations.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation on a KMS key in a different Amazon Web Services account, specify the key ARN in the value of the KeyId parameter.

Required permissions: kms:CreateGrant (key policy)

Related operations:

• ListGrants

• ListRetirableGrants

• RetireGrant

• RevokeGrant

Creates a unique customer managed KMS key in your Amazon Web Services account and Region. You can use a KMS key in cryptographic operations, such as encryption and signing. Some Amazon Web Services services let you use KMS keys that you create and manage to protect your service resources.

A KMS key is a logical representation of a cryptographic key. In addition to the key material used in cryptographic operations, a KMS key includes metadata, such as the key ID, key policy, creation date, description, and key state. For details, see Managing keys in the Key Management Service Developer Guide

Use the parameters of CreateKey to specify the type of KMS key, the source of its key material, its key policy, description, tags, and other properties.

To create different types of KMS keys, use the following guidance:

Symmetric encryption KMS key

By default, CreateKey creates a symmetric encryption KMS key with key material that KMS generates. This is the basic and most widely used type of KMS key, and provides the best performance.

To create a symmetric encryption KMS key, you don’t need to specify any parameters. The default value for KeySpec, SYMMETRIC_DEFAULT, the default value for KeyUsage, ENCRYPT_DECRYPT, and the default value for Origin, AWS_KMS, create a symmetric encryption KMS key with KMS key material.

If you need a key for basic encryption and decryption or you are creating a KMS key to protect your resources in an Amazon Web Services service, create a symmetric encryption KMS key. The key material in a symmetric encryption key never leaves KMS unencrypted. You can use a symmetric encryption KMS key to encrypt and decrypt data up to 4,096 bytes, but they are typically used to generate data keys and data keys pairs. For details, see GenerateDataKey and GenerateDataKeyPair.

Asymmetric KMS keys

To create an asymmetric KMS key, use the KeySpec parameter to specify the type of key material in the KMS key. Then, use the KeyUsage parameter to determine whether the KMS key will be used to encrypt and decrypt or sign and verify. You can’t change these properties after the KMS key is created.

Asymmetric KMS keys contain an RSA key pair, Elliptic Curve (ECC) key pair, or an SM2 key pair (China Regions only). The private key in an asymmetric KMS key never leaves KMS unencrypted. However, you can use the GetPublicKey operation to download the public key so it can be used outside of KMS. KMS keys with RSA or SM2 key pairs can be used to encrypt or decrypt data or sign and verify messages (but not both). KMS keys with ECC key pairs can be used only to sign and verify messages. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.

HMAC KMS key

To create an HMAC KMS key, set the KeySpec parameter to a key spec value for HMAC KMS keys. Then set the KeyUsage parameter to GENERATE_VERIFY_MAC. You must set the key usage even though GENERATE_VERIFY_MAC is the only valid key usage value for HMAC KMS keys. You can’t change these properties after the KMS key is created.

HMAC KMS keys are symmetric keys that never leave KMS unencrypted. You can use HMAC keys to generate (GenerateMac) and verify (VerifyMac) HMAC codes for messages up to 4096 bytes.

HMAC KMS keys are not supported in all Amazon Web Services Regions. If you try to create an HMAC KMS key in an Amazon Web Services Region in which HMAC keys are not supported, the CreateKey operation returns an UnsupportedOperationException. For a list of Regions in which HMAC KMS keys are supported, see HMAC keys in KMS in the Key Management Service Developer Guide.

Multi-Region primary keys

Imported key material

To create a multi-Region primary key in the local Amazon Web Services Region, use the MultiRegion parameter with a value of True. To create a multi-Region replica key, that is, a KMS key with the same key ID and key material as a primary key, but in a different Amazon Web Services Region, use the ReplicateKey operation. To change a replica key to a primary key, and its primary key to a replica key, use the UpdatePrimaryRegion operation.

You can create multi-Region KMS keys for all supported KMS key types: symmetric encryption KMS keys, HMAC KMS keys, asymmetric encryption KMS keys, and asymmetric signing KMS keys. You can also create multi-Region keys with imported key material. However, you can’t create multi-Region keys in a custom key store.

This operation supports multi-Region keys, an KMS feature that lets you create multiple interoperable KMS keys in different Amazon Web Services Regions. Because these KMS keys have the same key ID, key material, and other metadata, you can use them interchangeably to encrypt data in one Amazon Web Services Region and decrypt it in a different Amazon Web Services Region without re-encrypting the data or making a cross-Region call. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.

To import your own key material into a KMS key, begin by creating a symmetric encryption KMS key with no key material. To do this, use the Origin parameter of CreateKey with a value of EXTERNAL. Next, use GetParametersForImport operation to get a public key and import token, and use the public key to encrypt your key material. Then, use ImportKeyMaterial with your import token to import the key material. For step-by-step instructions, see Importing Key Material in the Key Management Service Developer Guide.

This feature supports only symmetric encryption KMS keys, including multi-Region symmetric encryption KMS keys. You cannot import key material into any other type of KMS key.

To create a multi-Region primary key with imported key material, use the Origin parameter of CreateKey with a value of EXTERNAL and the MultiRegion parameter with a value of True. To create replicas of the multi-Region primary key, use the ReplicateKey operation. For instructions, see Importing key material into multi-Region keys. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.

Custom key store

A custom key store lets you protect your Amazon Web Services resources using keys in a backing key store that you own and manage. When you request a cryptographic operation with a KMS key in a custom key store, the operation is performed in the backing key store using its cryptographic keys.

KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key manager outside of Amazon Web Services. When you create a KMS key in an CloudHSM key store, KMS generates an encryption key in the CloudHSM cluster and associates it with the KMS key. When you create a KMS key in an external key store, you specify an existing encryption key in the external key manager.

Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.

Before you create a KMS key in a custom key store, the ConnectionState of the key store must be CONNECTED. To connect the custom key store, use the ConnectCustomKeyStore operation. To find the ConnectionState, use the DescribeCustomKeyStores operation.

To create a KMS key in a custom key store, use the CustomKeyStoreId. Use the default KeySpec value, SYMMETRIC_DEFAULT, and the default KeyUsage value, ENCRYPT_DECRYPT to create a symmetric encryption key. No other key type is supported in a custom key store.

To create a KMS key in an CloudHSM key store, use the Origin parameter with a value of AWS_CLOUDHSM. The CloudHSM cluster that is associated with the custom key store must have at least two active HSMs in different Availability Zones in the Amazon Web Services Region.

To create a KMS key in an external key store, use the Origin parameter with a value of EXTERNAL_KEY_STORE and an XksKeyId parameter that identifies an existing external key.

Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.

Cross-account use: No. You cannot use this operation to create a KMS key in a different Amazon Web Services account.

Required permissions: kms:CreateKey (IAM policy). To use the Tags parameter, kms:TagResource (IAM policy). For examples and information about related permissions, see Allow a user to create KMS keys in the Key Management Service Developer Guide.

Related operations:

• DescribeKey

• ListKeys

• ScheduleKeyDeletion

Creates a unique customer managed KMS key in your Amazon Web Services account and Region. You can use a KMS key in cryptographic operations, such as encryption and signing. Some Amazon Web Services services let you use KMS keys that you create and manage to protect your service resources.

A KMS key is a logical representation of a cryptographic key. In addition to the key material used in cryptographic operations, a KMS key includes metadata, such as the key ID, key policy, creation date, description, and key state. For details, see Managing keys in the Key Management Service Developer Guide

Use the parameters of CreateKey to specify the type of KMS key, the source of its key material, its key policy, description, tags, and other properties.

To create different types of KMS keys, use the following guidance:

Symmetric encryption KMS key

By default, CreateKey creates a symmetric encryption KMS key with key material that KMS generates. This is the basic and most widely used type of KMS key, and provides the best performance.

To create a symmetric encryption KMS key, you don’t need to specify any parameters. The default value for KeySpec, SYMMETRIC_DEFAULT, the default value for KeyUsage, ENCRYPT_DECRYPT, and the default value for Origin, AWS_KMS, create a symmetric encryption KMS key with KMS key material.

If you need a key for basic encryption and decryption or you are creating a KMS key to protect your resources in an Amazon Web Services service, create a symmetric encryption KMS key. The key material in a symmetric encryption key never leaves KMS unencrypted. You can use a symmetric encryption KMS key to encrypt and decrypt data up to 4,096 bytes, but they are typically used to generate data keys and data keys pairs. For details, see GenerateDataKey and GenerateDataKeyPair.

Asymmetric KMS keys

To create an asymmetric KMS key, use the KeySpec parameter to specify the type of key material in the KMS key. Then, use the KeyUsage parameter to determine whether the KMS key will be used to encrypt and decrypt or sign and verify. You can’t change these properties after the KMS key is created.

Asymmetric KMS keys contain an RSA key pair, Elliptic Curve (ECC) key pair, or an SM2 key pair (China Regions only). The private key in an asymmetric KMS key never leaves KMS unencrypted. However, you can use the GetPublicKey operation to download the public key so it can be used outside of KMS. KMS keys with RSA or SM2 key pairs can be used to encrypt or decrypt data or sign and verify messages (but not both). KMS keys with ECC key pairs can be used only to sign and verify messages. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.

HMAC KMS key

To create an HMAC KMS key, set the KeySpec parameter to a key spec value for HMAC KMS keys. Then set the KeyUsage parameter to GENERATE_VERIFY_MAC. You must set the key usage even though GENERATE_VERIFY_MAC is the only valid key usage value for HMAC KMS keys. You can’t change these properties after the KMS key is created.

HMAC KMS keys are symmetric keys that never leave KMS unencrypted. You can use HMAC keys to generate (GenerateMac) and verify (VerifyMac) HMAC codes for messages up to 4096 bytes.

HMAC KMS keys are not supported in all Amazon Web Services Regions. If you try to create an HMAC KMS key in an Amazon Web Services Region in which HMAC keys are not supported, the CreateKey operation returns an UnsupportedOperationException. For a list of Regions in which HMAC KMS keys are supported, see HMAC keys in KMS in the Key Management Service Developer Guide.

Multi-Region primary keys

Imported key material

To create a multi-Region primary key in the local Amazon Web Services Region, use the MultiRegion parameter with a value of True. To create a multi-Region replica key, that is, a KMS key with the same key ID and key material as a primary key, but in a different Amazon Web Services Region, use the ReplicateKey operation. To change a replica key to a primary key, and its primary key to a replica key, use the UpdatePrimaryRegion operation.

You can create multi-Region KMS keys for all supported KMS key types: symmetric encryption KMS keys, HMAC KMS keys, asymmetric encryption KMS keys, and asymmetric signing KMS keys. You can also create multi-Region keys with imported key material. However, you can’t create multi-Region keys in a custom key store.

This operation supports multi-Region keys, an KMS feature that lets you create multiple interoperable KMS keys in different Amazon Web Services Regions. Because these KMS keys have the same key ID, key material, and other metadata, you can use them interchangeably to encrypt data in one Amazon Web Services Region and decrypt it in a different Amazon Web Services Region without re-encrypting the data or making a cross-Region call. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.

To import your own key material into a KMS key, begin by creating a symmetric encryption KMS key with no key material. To do this, use the Origin parameter of CreateKey with a value of EXTERNAL. Next, use GetParametersForImport operation to get a public key and import token, and use the public key to encrypt your key material. Then, use ImportKeyMaterial with your import token to import the key material. For step-by-step instructions, see Importing Key Material in the Key Management Service Developer Guide.

This feature supports only symmetric encryption KMS keys, including multi-Region symmetric encryption KMS keys. You cannot import key material into any other type of KMS key.

To create a multi-Region primary key with imported key material, use the Origin parameter of CreateKey with a value of EXTERNAL and the MultiRegion parameter with a value of True. To create replicas of the multi-Region primary key, use the ReplicateKey operation. For instructions, see Importing key material into multi-Region keys. For more information about multi-Region keys, see Multi-Region keys in KMS in the Key Management Service Developer Guide.

Custom key store

A custom key store lets you protect your Amazon Web Services resources using keys in a backing key store that you own and manage. When you request a cryptographic operation with a KMS key in a custom key store, the operation is performed in the backing key store using its cryptographic keys.

KMS supports CloudHSM key stores backed by an CloudHSM cluster and external key stores backed by an external key manager outside of Amazon Web Services. When you create a KMS key in an CloudHSM key store, KMS generates an encryption key in the CloudHSM cluster and associates it with the KMS key. When you create a KMS key in an external key store, you specify an existing encryption key in the external key manager.

Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.

Before you create a KMS key in a custom key store, the ConnectionState of the key store must be CONNECTED. To connect the custom key store, use the ConnectCustomKeyStore operation. To find the ConnectionState, use the DescribeCustomKeyStores operation.

To create a KMS key in a custom key store, use the CustomKeyStoreId. Use the default KeySpec value, SYMMETRIC_DEFAULT, and the default KeyUsage value, ENCRYPT_DECRYPT to create a symmetric encryption key. No other key type is supported in a custom key store.

To create a KMS key in an CloudHSM key store, use the Origin parameter with a value of AWS_CLOUDHSM. The CloudHSM cluster that is associated with the custom key store must have at least two active HSMs in different Availability Zones in the Amazon Web Services Region.

To create a KMS key in an external key store, use the Origin parameter with a value of EXTERNAL_KEY_STORE and an XksKeyId parameter that identifies an existing external key.

Some external key managers provide a simpler method for creating a KMS key in an external key store. For details, see your external key manager documentation.

Cross-account use: No. You cannot use this operation to create a KMS key in a different Amazon Web Services account.

Required permissions: kms:CreateKey (IAM policy). To use the Tags parameter, kms:TagResource (IAM policy). For examples and information about related permissions, see Allow a user to create KMS keys in the Key Management Service Developer Guide.

Related operations:

• DescribeKey

• ListKeys

• ScheduleKeyDeletion

Decrypts ciphertext that was encrypted by a KMS key using any of the following operations:

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyWithoutPlaintext

• GenerateDataKeyPairWithoutPlaintext

You can use this operation to decrypt ciphertext that was encrypted under a symmetric encryption KMS key or an asymmetric encryption KMS key. When the KMS key is asymmetric, you must specify the KMS key and the encryption algorithm that was used to encrypt the ciphertext. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.

The Decrypt operation also decrypts ciphertext that was encrypted outside of KMS by the public key in an KMS asymmetric KMS key. However, it cannot decrypt symmetric ciphertext produced by other libraries, such as the Amazon Web Services Encryption SDK or Amazon S3 client-side encryption. These libraries return a ciphertext format that is incompatible with KMS.

If the ciphertext was encrypted under a symmetric encryption KMS key, the KeyId parameter is optional. KMS can get this information from metadata that it adds to the symmetric ciphertext blob. This feature adds durability to your implementation by ensuring that authorized users can decrypt ciphertext decades after it was encrypted, even if they’ve lost track of the key ID. However, specifying the KMS key is always recommended as a best practice. When you use the KeyId parameter to specify a KMS key, KMS only uses the KMS key you specify. If the ciphertext was encrypted under a different KMS key, the Decrypt operation fails. This practice ensures that you use the KMS key that you intend.

Whenever possible, use key policies to give users permission to call the Decrypt operation on a particular KMS key, instead of using &IAM; policies. Otherwise, you might create an &IAM; policy that gives the user Decrypt permission on all KMS keys. This user could decrypt ciphertext that was encrypted by KMS keys in other accounts if the key policy for the cross-account KMS key permits it. If you must use an IAM policy for Decrypt permissions, limit the user to particular KMS keys or particular trusted accounts. For details, see Best practices for IAM policies in the Key Management Service Developer Guide.

Decrypt also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call Decrypt for a Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. Instead of the plaintext data, the response includes the plaintext data encrypted with the public key from the attestation document (CiphertextForRecipient).For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. If you use the KeyId parameter to identify a KMS key in a different Amazon Web Services account, specify the key ARN or the alias ARN of the KMS key.

Required permissions: kms:Decrypt (key policy)

Related operations:

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• ReEncrypt

Decrypts ciphertext that was encrypted by a KMS key using any of the following operations:

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyWithoutPlaintext

• GenerateDataKeyPairWithoutPlaintext

You can use this operation to decrypt ciphertext that was encrypted under a symmetric encryption KMS key or an asymmetric encryption KMS key. When the KMS key is asymmetric, you must specify the KMS key and the encryption algorithm that was used to encrypt the ciphertext. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide.

The Decrypt operation also decrypts ciphertext that was encrypted outside of KMS by the public key in an KMS asymmetric KMS key. However, it cannot decrypt symmetric ciphertext produced by other libraries, such as the Amazon Web Services Encryption SDK or Amazon S3 client-side encryption. These libraries return a ciphertext format that is incompatible with KMS.

If the ciphertext was encrypted under a symmetric encryption KMS key, the KeyId parameter is optional. KMS can get this information from metadata that it adds to the symmetric ciphertext blob. This feature adds durability to your implementation by ensuring that authorized users can decrypt ciphertext decades after it was encrypted, even if they’ve lost track of the key ID. However, specifying the KMS key is always recommended as a best practice. When you use the KeyId parameter to specify a KMS key, KMS only uses the KMS key you specify. If the ciphertext was encrypted under a different KMS key, the Decrypt operation fails. This practice ensures that you use the KMS key that you intend.

Whenever possible, use key policies to give users permission to call the Decrypt operation on a particular KMS key, instead of using &IAM; policies. Otherwise, you might create an &IAM; policy that gives the user Decrypt permission on all KMS keys. This user could decrypt ciphertext that was encrypted by KMS keys in other accounts if the key policy for the cross-account KMS key permits it. If you must use an IAM policy for Decrypt permissions, limit the user to particular KMS keys or particular trusted accounts. For details, see Best practices for IAM policies in the Key Management Service Developer Guide.

Decrypt also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call Decrypt for a Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. Instead of the plaintext data, the response includes the plaintext data encrypted with the public key from the attestation document (CiphertextForRecipient).For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. If you use the KeyId parameter to identify a KMS key in a different Amazon Web Services account, specify the key ARN or the alias ARN of the KMS key.

Required permissions: kms:Decrypt (key policy)

Related operations:

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• ReEncrypt

Deletes the specified alias.

Because an alias is not a property of a KMS key, you can delete and change the aliases of a KMS key without affecting the KMS key. Also, aliases do not appear in the response from the DescribeKey operation. To get the aliases of all KMS keys, use the ListAliases operation.

Each KMS key can have multiple aliases. To change the alias of a KMS key, use DeleteAlias to delete the current alias and CreateAlias to create a new alias. To associate an existing alias with a different KMS key, call UpdateAlias.

Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.

Required permissions

• kms:DeleteAlias on the alias (IAM policy).

• kms:DeleteAlias on the KMS key (key policy).

For details, see Controlling access to aliases in the Key Management Service Developer Guide.

Related operations:

• CreateAlias

• ListAliases

• UpdateAlias

Deletes the specified alias.

Because an alias is not a property of a KMS key, you can delete and change the aliases of a KMS key without affecting the KMS key. Also, aliases do not appear in the response from the DescribeKey operation. To get the aliases of all KMS keys, use the ListAliases operation.

Each KMS key can have multiple aliases. To change the alias of a KMS key, use DeleteAlias to delete the current alias and CreateAlias to create a new alias. To associate an existing alias with a different KMS key, call UpdateAlias.

Cross-account use: No. You cannot perform this operation on an alias in a different Amazon Web Services account.

Required permissions

• kms:DeleteAlias on the alias (IAM policy).

• kms:DeleteAlias on the KMS key (key policy).

For details, see Controlling access to aliases in the Key Management Service Developer Guide.

Related operations:

• CreateAlias

• ListAliases

• UpdateAlias

Deletes a custom key store. This operation does not affect any backing elements of the custom key store. It does not delete the CloudHSM cluster that is associated with an CloudHSM key store, or affect any users or keys in the cluster. For an external key store, it does not affect the external key store proxy, external key manager, or any external keys.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

The custom key store that you delete cannot contain any KMS keys. Before deleting the key store, verify that you will never need to use any of the KMS keys in the key store for any cryptographic operations. Then, use ScheduleKeyDeletion to delete the KMS keys from the key store. After the required waiting period expires and all KMS keys are deleted from the custom key store, use DisconnectCustomKeyStore to disconnect the key store from KMS. Then, you can delete the custom key store.

For keys in an CloudHSM key store, the ScheduleKeyDeletion operation makes a best effort to delete the key material from the associated cluster. However, you might need to manually delete the orphaned key material from the cluster and its backups. KMS never creates, manages, or deletes cryptographic keys in the external key manager associated with an external key store. You must manage them using your external key manager tools.

Instead of deleting the custom key store, consider using the DisconnectCustomKeyStore operation to disconnect the custom key store from its backing key store. While the key store is disconnected, you cannot create or use the KMS keys in the key store. But, you do not need to delete KMS keys and you can reconnect a disconnected custom key store at any time.

If the operation succeeds, it returns a JSON object with no properties.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DeleteCustomKeyStore (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Deletes a custom key store. This operation does not affect any backing elements of the custom key store. It does not delete the CloudHSM cluster that is associated with an CloudHSM key store, or affect any users or keys in the cluster. For an external key store, it does not affect the external key store proxy, external key manager, or any external keys.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

The custom key store that you delete cannot contain any KMS keys. Before deleting the key store, verify that you will never need to use any of the KMS keys in the key store for any cryptographic operations. Then, use ScheduleKeyDeletion to delete the KMS keys from the key store. After the required waiting period expires and all KMS keys are deleted from the custom key store, use DisconnectCustomKeyStore to disconnect the key store from KMS. Then, you can delete the custom key store.

For keys in an CloudHSM key store, the ScheduleKeyDeletion operation makes a best effort to delete the key material from the associated cluster. However, you might need to manually delete the orphaned key material from the cluster and its backups. KMS never creates, manages, or deletes cryptographic keys in the external key manager associated with an external key store. You must manage them using your external key manager tools.

Instead of deleting the custom key store, consider using the DisconnectCustomKeyStore operation to disconnect the custom key store from its backing key store. While the key store is disconnected, you cannot create or use the KMS keys in the key store. But, you do not need to delete KMS keys and you can reconnect a disconnected custom key store at any time.

If the operation succeeds, it returns a JSON object with no properties.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DeleteCustomKeyStore (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DescribeCustomKeyStores

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Deletes key material that you previously imported. This operation makes the specified KMS key unusable. For more information about importing key material into KMS, see Importing Key Material in the Key Management Service Developer Guide.

When the specified KMS key is in the PendingDeletion state, this operation does not change the KMS key’s state. Otherwise, it changes the KMS key’s state to PendingImport.

After you delete key material, you can use ImportKeyMaterial to reimport the same key material into the KMS key.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DeleteImportedKeyMaterial (key policy)

Related operations:

• GetParametersForImport

• ImportKeyMaterial

Deletes key material that you previously imported. This operation makes the specified KMS key unusable. For more information about importing key material into KMS, see Importing Key Material in the Key Management Service Developer Guide.

When the specified KMS key is in the PendingDeletion state, this operation does not change the KMS key’s state. Otherwise, it changes the KMS key’s state to PendingImport.

After you delete key material, you can use ImportKeyMaterial to reimport the same key material into the KMS key.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DeleteImportedKeyMaterial (key policy)

Related operations:

• GetParametersForImport

• ImportKeyMaterial

Gets information about custom key stores in the account and Region.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

By default, this operation returns information about all custom key stores in the account and Region. To get only information about a particular custom key store, use either the CustomKeyStoreName or CustomKeyStoreId parameter (but not both).

To determine whether the custom key store is connected to its CloudHSM cluster or external key store proxy, use the ConnectionState element in the response. If an attempt to connect the custom key store failed, the ConnectionState value is FAILED and the ConnectionErrorCode element in the response indicates the cause of the failure. For help interpreting the ConnectionErrorCode, see CustomKeyStoresListEntry.

Custom key stores have a DISCONNECTED connection state if the key store has never been connected or you used the DisconnectCustomKeyStore operation to disconnect it. Otherwise, the connection state is CONNECTED. If your custom key store connection state is CONNECTED but you are having trouble using it, verify that the backing store is active and available. For an CloudHSM key store, verify that the associated CloudHSM cluster is active and contains the minimum number of HSMs required for the operation, if any. For an external key store, verify that the external key store proxy and its associated external key manager are reachable and enabled.

For help repairing your CloudHSM key store, see the Troubleshooting CloudHSM key stores. For help repairing your external key store, see the Troubleshooting external key stores. Both topics are in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DescribeCustomKeyStores (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Gets information about custom key stores in the account and Region.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

By default, this operation returns information about all custom key stores in the account and Region. To get only information about a particular custom key store, use either the CustomKeyStoreName or CustomKeyStoreId parameter (but not both).

To determine whether the custom key store is connected to its CloudHSM cluster or external key store proxy, use the ConnectionState element in the response. If an attempt to connect the custom key store failed, the ConnectionState value is FAILED and the ConnectionErrorCode element in the response indicates the cause of the failure. For help interpreting the ConnectionErrorCode, see CustomKeyStoresListEntry.

Custom key stores have a DISCONNECTED connection state if the key store has never been connected or you used the DisconnectCustomKeyStore operation to disconnect it. Otherwise, the connection state is CONNECTED. If your custom key store connection state is CONNECTED but you are having trouble using it, verify that the backing store is active and available. For an CloudHSM key store, verify that the associated CloudHSM cluster is active and contains the minimum number of HSMs required for the operation, if any. For an external key store, verify that the external key store proxy and its associated external key manager are reachable and enabled.

For help repairing your CloudHSM key store, see the Troubleshooting CloudHSM key stores. For help repairing your external key store, see the Troubleshooting external key stores. Both topics are in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DescribeCustomKeyStores (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DisconnectCustomKeyStore

• UpdateCustomKeyStore

Provides detailed information about a KMS key. You can run DescribeKey on a customer managed key or an Amazon Web Services managed key.

This detailed information includes the key ARN, creation date (and deletion date, if applicable), the key state, and the origin and expiration date (if any) of the key material. It includes fields, like KeySpec, that help you distinguish different types of KMS keys. It also displays the key usage (encryption, signing, or generating and verifying MACs) and the algorithms that the KMS key supports.

For multi-Region keys, DescribeKey displays the primary key and all related replica keys. For KMS keys in CloudHSM key stores, it includes information about the key store, such as the key store ID and the CloudHSM cluster ID. For KMS keys in external key stores, it includes the custom key store ID and the ID of the external key.

DescribeKey does not return the following information:

• Aliases associated with the KMS key. To get this information, use ListAliases.

• Whether automatic key rotation is enabled on the KMS key. To get this information, use GetKeyRotationStatus. Also, some key states prevent a KMS key from being automatically rotated. For details, see How Automatic Key Rotation Works in the Key Management Service Developer Guide.

• Tags on the KMS key. To get this information, use ListResourceTags.

• Key policies and grants on the KMS key. To get this information, use GetKeyPolicy and ListGrants.

In general, DescribeKey is a non-mutating operation. It returns data about KMS keys, but doesn’t change them. However, Amazon Web Services services use DescribeKey to create Amazon Web Services managed keys from a predefined Amazon Web Services alias with no key ID.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:DescribeKey (key policy)

Related operations:

• GetKeyPolicy

• GetKeyRotationStatus

• ListAliases

• ListGrants

• ListKeys

• ListResourceTags

• ListRetirableGrants

Provides detailed information about a KMS key. You can run DescribeKey on a customer managed key or an Amazon Web Services managed key.

This detailed information includes the key ARN, creation date (and deletion date, if applicable), the key state, and the origin and expiration date (if any) of the key material. It includes fields, like KeySpec, that help you distinguish different types of KMS keys. It also displays the key usage (encryption, signing, or generating and verifying MACs) and the algorithms that the KMS key supports.

For multi-Region keys, DescribeKey displays the primary key and all related replica keys. For KMS keys in CloudHSM key stores, it includes information about the key store, such as the key store ID and the CloudHSM cluster ID. For KMS keys in external key stores, it includes the custom key store ID and the ID of the external key.

DescribeKey does not return the following information:

• Aliases associated with the KMS key. To get this information, use ListAliases.

• Whether automatic key rotation is enabled on the KMS key. To get this information, use GetKeyRotationStatus. Also, some key states prevent a KMS key from being automatically rotated. For details, see How Automatic Key Rotation Works in the Key Management Service Developer Guide.

• Tags on the KMS key. To get this information, use ListResourceTags.

• Key policies and grants on the KMS key. To get this information, use GetKeyPolicy and ListGrants.

In general, DescribeKey is a non-mutating operation. It returns data about KMS keys, but doesn’t change them. However, Amazon Web Services services use DescribeKey to create Amazon Web Services managed keys from a predefined Amazon Web Services alias with no key ID.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:DescribeKey (key policy)

Related operations:

• GetKeyPolicy

• GetKeyRotationStatus

• ListAliases

• ListGrants

• ListKeys

• ListResourceTags

• ListRetirableGrants

Sets the state of a KMS key to disabled. This change temporarily prevents use of the KMS key for cryptographic operations.

For more information about how key state affects the use of a KMS key, see Key states of KMS keys in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DisableKey (key policy)

Related operations: EnableKey

Sets the state of a KMS key to disabled. This change temporarily prevents use of the KMS key for cryptographic operations.

For more information about how key state affects the use of a KMS key, see Key states of KMS keys in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DisableKey (key policy)

Related operations: EnableKey

Disables automatic rotation of the key material of the specified symmetric encryption KMS key.

Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.

You can enable (EnableKeyRotation) and disable automatic rotation of the key material in customer managed KMS keys. Key material rotation of Amazon Web Services managed KMS keys is not configurable. KMS always rotates the key material for every year. Rotation of Amazon Web Services owned KMS keys varies.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DisableKeyRotation (key policy)

Related operations:

• EnableKeyRotation

• GetKeyRotationStatus

Disables automatic rotation of the key material of the specified symmetric encryption KMS key.

Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.

You can enable (EnableKeyRotation) and disable automatic rotation of the key material in customer managed KMS keys. Key material rotation of Amazon Web Services managed KMS keys is not configurable. KMS always rotates the key material for every year. Rotation of Amazon Web Services owned KMS keys varies.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:DisableKeyRotation (key policy)

Related operations:

• EnableKeyRotation

• GetKeyRotationStatus

Disconnects the custom key store from its backing key store. This operation disconnects an CloudHSM key store from its associated CloudHSM cluster or disconnects an external key store from the external key store proxy that communicates with your external key manager.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

While a custom key store is disconnected, you can manage the custom key store and its KMS keys, but you cannot create or use its KMS keys. You can reconnect the custom key store at any time.

When you disconnect a custom key store, its ConnectionState changes to Disconnected. To find the connection state of a custom key store, use the DescribeCustomKeyStores operation. To reconnect a custom key store, use the ConnectCustomKeyStore operation.

If the operation succeeds, it returns a JSON object with no properties.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DisconnectCustomKeyStore (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• UpdateCustomKeyStore

Disconnects the custom key store from its backing key store. This operation disconnects an CloudHSM key store from its associated CloudHSM cluster or disconnects an external key store from the external key store proxy that communicates with your external key manager.

This operation is part of the custom key stores feature in KMS, which combines the convenience and extensive integration of KMS with the isolation and control of a key store that you own and manage.

While a custom key store is disconnected, you can manage the custom key store and its KMS keys, but you cannot create or use its KMS keys. You can reconnect the custom key store at any time.

When you disconnect a custom key store, its ConnectionState changes to Disconnected. To find the connection state of a custom key store, use the DescribeCustomKeyStores operation. To reconnect a custom key store, use the ConnectCustomKeyStore operation.

If the operation succeeds, it returns a JSON object with no properties.

Cross-account use: No. You cannot perform this operation on a custom key store in a different Amazon Web Services account.

Required permissions: kms:DisconnectCustomKeyStore (IAM policy)

Related operations:

• ConnectCustomKeyStore

• CreateCustomKeyStore

• DeleteCustomKeyStore

• DescribeCustomKeyStores

• UpdateCustomKeyStore

Sets the key state of a KMS key to enabled. This allows you to use the KMS key for cryptographic operations.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:EnableKey (key policy)

Related operations: DisableKey

Sets the key state of a KMS key to enabled. This allows you to use the KMS key for cryptographic operations.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:EnableKey (key policy)

Related operations: DisableKey

Enables automatic rotation of the key material of the specified symmetric encryption KMS key.

When you enable automatic rotation of acustomer managed KMS key, KMS rotates the key material of the KMS key one year (approximately 365 days) from the enable date and every year thereafter. You can monitor rotation of the key material for your KMS keys in CloudTrail and Amazon CloudWatch. To disable rotation of the key material in a customer managed KMS key, use the DisableKeyRotation operation.

Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.

You cannot enable or disable automatic rotation Amazon Web Services managed KMS keys. KMS always rotates the key material of Amazon Web Services managed keys every year. Rotation of Amazon Web Services owned KMS keys varies.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:EnableKeyRotation (key policy)

Related operations:

• DisableKeyRotation

• GetKeyRotationStatus

Enables automatic rotation of the key material of the specified symmetric encryption KMS key.

When you enable automatic rotation of acustomer managed KMS key, KMS rotates the key material of the KMS key one year (approximately 365 days) from the enable date and every year thereafter. You can monitor rotation of the key material for your KMS keys in CloudTrail and Amazon CloudWatch. To disable rotation of the key material in a customer managed KMS key, use the DisableKeyRotation operation.

Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key.

You cannot enable or disable automatic rotation Amazon Web Services managed KMS keys. KMS always rotates the key material of Amazon Web Services managed keys every year. Rotation of Amazon Web Services owned KMS keys varies.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:EnableKeyRotation (key policy)

Related operations:

• DisableKeyRotation

• GetKeyRotationStatus

Encrypts plaintext of up to 4,096 bytes using a KMS key. You can use a symmetric or asymmetric KMS key with a KeyUsage of ENCRYPT_DECRYPT.

You can use this operation to encrypt small amounts of arbitrary data, such as a personal identifier or database password, or other sensitive information. You don’t need to use the Encrypt operation to encrypt a data key. The GenerateDataKey and GenerateDataKeyPair operations return a plaintext data key and an encrypted copy of that data key.

If you use a symmetric encryption KMS key, you can use an encryption context to add additional security to your encryption operation. If you specify an EncryptionContext when encrypting data, you must specify the same encryption context (a case-sensitive exact match) when decrypting the data. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

If you specify an asymmetric KMS key, you must also specify the encryption algorithm. The algorithm must be compatible with the KMS key spec.

The maximum size of the data that you can encrypt varies with the type of KMS key and the encryption algorithm that you choose.

• Symmetric encryption KMS keys

  • SYMMETRIC_DEFAULT: 4096 bytes

• RSA_2048

  • RSAES_OAEP_SHA_1: 214 bytes

  • RSAES_OAEP_SHA_256: 190 bytes

• RSA_3072

  • RSAES_OAEP_SHA_1: 342 bytes

  • RSAES_OAEP_SHA_256: 318 bytes

• RSA_4096

  • RSAES_OAEP_SHA_1: 470 bytes

  • RSAES_OAEP_SHA_256: 446 bytes

• SM2PKE: 1024 bytes (China Regions only)

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:Encrypt (key policy)

Related operations:

• Decrypt

• GenerateDataKey

• GenerateDataKeyPair

Encrypts plaintext of up to 4,096 bytes using a KMS key. You can use a symmetric or asymmetric KMS key with a KeyUsage of ENCRYPT_DECRYPT.

You can use this operation to encrypt small amounts of arbitrary data, such as a personal identifier or database password, or other sensitive information. You don’t need to use the Encrypt operation to encrypt a data key. The GenerateDataKey and GenerateDataKeyPair operations return a plaintext data key and an encrypted copy of that data key.

If you use a symmetric encryption KMS key, you can use an encryption context to add additional security to your encryption operation. If you specify an EncryptionContext when encrypting data, you must specify the same encryption context (a case-sensitive exact match) when decrypting the data. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

If you specify an asymmetric KMS key, you must also specify the encryption algorithm. The algorithm must be compatible with the KMS key spec.

The maximum size of the data that you can encrypt varies with the type of KMS key and the encryption algorithm that you choose.

• Symmetric encryption KMS keys

  • SYMMETRIC_DEFAULT: 4096 bytes

• RSA_2048

  • RSAES_OAEP_SHA_1: 214 bytes

  • RSAES_OAEP_SHA_256: 190 bytes

• RSA_3072

  • RSAES_OAEP_SHA_1: 342 bytes

  • RSAES_OAEP_SHA_256: 318 bytes

• RSA_4096

  • RSAES_OAEP_SHA_1: 470 bytes

  • RSAES_OAEP_SHA_256: 446 bytes

• SM2PKE: 1024 bytes (China Regions only)

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:Encrypt (key policy)

Related operations:

• Decrypt

• GenerateDataKey

• GenerateDataKeyPair

Returns a unique symmetric data key for use outside of KMS. This operation returns a plaintext copy of the data key and a copy that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the plaintext key are random; they are not related to the caller or the KMS key. You can use the plaintext key to encrypt your data outside of KMS and store the encrypted data key with the encrypted data.

To generate a data key, specify the symmetric encryption KMS key that will be used to encrypt the data key. You cannot use an asymmetric KMS key to encrypt data keys. To get the type of your KMS key, use the DescribeKey operation.

You must also specify the length of the data key. Use either the KeySpec or NumberOfBytes parameters (but not both). For 128-bit and 256-bit data keys, use the KeySpec parameter.

To generate a 128-bit SM4 data key (China Regions only), specify a KeySpec value of AES_128 or a NumberOfBytes value of 16. The symmetric encryption key used in China Regions to encrypt your data key is an SM4 encryption key.

To get only an encrypted copy of the data key, use GenerateDataKeyWithoutPlaintext. To generate an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operation. To get a cryptographically secure random byte string, use GenerateRandom.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

GenerateDataKey also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateDataKey for an Amazon Web Services Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. GenerateDataKey returns a copy of the data key encrypted under the specified KMS key, as usual. But instead of a plaintext copy of the data key, the response includes a copy of the data key encrypted under the public key from the attestation document (CiphertextForRecipient). For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

How to use your data key

We recommend that you use the following pattern to encrypt data locally in your application. You can write your own code or use a client-side encryption library, such as the Amazon Web Services Encryption SDK, the Amazon DynamoDB Encryption Client, or Amazon S3 client-side encryption to do these tasks for you.

To encrypt data outside of KMS:

1. Use the GenerateDataKey operation to get a data key.

2. Use the plaintext data key (in the Plaintext field of the response) to encrypt your data outside of KMS. Then erase the plaintext data key from memory.

3. Store the encrypted data key (in the CiphertextBlob field of the response) with the encrypted data.

To decrypt data outside of KMS:

1. Use the Decrypt operation to decrypt the encrypted data key. The operation returns a plaintext copy of the data key.

2. Use the plaintext data key to decrypt data outside of KMS, then erase the plaintext data key from memory.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKey (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKeyPair

• GenerateDataKeyPairWithoutPlaintext

• GenerateDataKeyWithoutPlaintext

Returns a unique symmetric data key for use outside of KMS. This operation returns a plaintext copy of the data key and a copy that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the plaintext key are random; they are not related to the caller or the KMS key. You can use the plaintext key to encrypt your data outside of KMS and store the encrypted data key with the encrypted data.

To generate a data key, specify the symmetric encryption KMS key that will be used to encrypt the data key. You cannot use an asymmetric KMS key to encrypt data keys. To get the type of your KMS key, use the DescribeKey operation.

You must also specify the length of the data key. Use either the KeySpec or NumberOfBytes parameters (but not both). For 128-bit and 256-bit data keys, use the KeySpec parameter.

To generate a 128-bit SM4 data key (China Regions only), specify a KeySpec value of AES_128 or a NumberOfBytes value of 16. The symmetric encryption key used in China Regions to encrypt your data key is an SM4 encryption key.

To get only an encrypted copy of the data key, use GenerateDataKeyWithoutPlaintext. To generate an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operation. To get a cryptographically secure random byte string, use GenerateRandom.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

GenerateDataKey also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateDataKey for an Amazon Web Services Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. GenerateDataKey returns a copy of the data key encrypted under the specified KMS key, as usual. But instead of a plaintext copy of the data key, the response includes a copy of the data key encrypted under the public key from the attestation document (CiphertextForRecipient). For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

How to use your data key

We recommend that you use the following pattern to encrypt data locally in your application. You can write your own code or use a client-side encryption library, such as the Amazon Web Services Encryption SDK, the Amazon DynamoDB Encryption Client, or Amazon S3 client-side encryption to do these tasks for you.

To encrypt data outside of KMS:

1. Use the GenerateDataKey operation to get a data key.

2. Use the plaintext data key (in the Plaintext field of the response) to encrypt your data outside of KMS. Then erase the plaintext data key from memory.

3. Store the encrypted data key (in the CiphertextBlob field of the response) with the encrypted data.

To decrypt data outside of KMS:

1. Use the Decrypt operation to decrypt the encrypted data key. The operation returns a plaintext copy of the data key.

2. Use the plaintext data key to decrypt data outside of KMS, then erase the plaintext data key from memory.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKey (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKeyPair

• GenerateDataKeyPairWithoutPlaintext

• GenerateDataKeyWithoutPlaintext

Returns a unique asymmetric data key pair for use outside of KMS. This operation returns a plaintext public key, a plaintext private key, and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. You can use the data key pair to perform asymmetric cryptography and implement digital signatures outside of KMS. The bytes in the keys are random; they not related to the caller or to the KMS key that is used to encrypt the private key.

You can use the public key that GenerateDataKeyPair returns to encrypt data or verify a signature outside of KMS. Then, store the encrypted private key with the data. When you are ready to decrypt data or sign a message, you can use the Decrypt operation to decrypt the encrypted private key.

To generate a data key pair, you must specify a symmetric encryption KMS key to encrypt the private key in a data key pair. You cannot use an asymmetric KMS key or a KMS key in a custom key store. To get the type and origin of your KMS key, use the DescribeKey operation.

Use the KeyPairSpec parameter to choose an RSA or Elliptic Curve (ECC) data key pair. In China Regions, you can also choose an SM2 data key pair. KMS recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs for either encryption or signing, but not both. However, KMS cannot enforce any restrictions on the use of data key pairs outside of KMS.

If you are using the data key pair to encrypt data, or for any operation where you don’t immediately need a private key, consider using the GenerateDataKeyPairWithoutPlaintext operation. GenerateDataKeyPairWithoutPlaintext returns a plaintext public key and an encrypted private key, but omits the plaintext private key that you need only to decrypt ciphertext or sign a message. Later, when you need to decrypt the data or sign a message, use the Decrypt operation to decrypt the encrypted private key in the data key pair.

GenerateDataKeyPair returns a unique data key pair for each request. The bytes in the keys are random; they are not related to the caller or the KMS key that is used to encrypt the private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified in RFC 5280. The private key is a DER-encoded PKCS8 PrivateKeyInfo, as specified in RFC 5958.

GenerateDataKeyPair also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateDataKeyPair for an Amazon Web Services Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. GenerateDataKeyPair returns the public data key and a copy of the private data key encrypted under the specified KMS key, as usual. But instead of a plaintext copy of the private data key (PrivateKeyPlaintext), the response includes a copy of the private data key encrypted under the public key from the attestation document (CiphertextForRecipient). For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyPair (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPairWithoutPlaintext

• GenerateDataKeyWithoutPlaintext

Returns a unique asymmetric data key pair for use outside of KMS. This operation returns a plaintext public key, a plaintext private key, and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. You can use the data key pair to perform asymmetric cryptography and implement digital signatures outside of KMS. The bytes in the keys are random; they not related to the caller or to the KMS key that is used to encrypt the private key.

You can use the public key that GenerateDataKeyPair returns to encrypt data or verify a signature outside of KMS. Then, store the encrypted private key with the data. When you are ready to decrypt data or sign a message, you can use the Decrypt operation to decrypt the encrypted private key.

To generate a data key pair, you must specify a symmetric encryption KMS key to encrypt the private key in a data key pair. You cannot use an asymmetric KMS key or a KMS key in a custom key store. To get the type and origin of your KMS key, use the DescribeKey operation.

Use the KeyPairSpec parameter to choose an RSA or Elliptic Curve (ECC) data key pair. In China Regions, you can also choose an SM2 data key pair. KMS recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs for either encryption or signing, but not both. However, KMS cannot enforce any restrictions on the use of data key pairs outside of KMS.

If you are using the data key pair to encrypt data, or for any operation where you don’t immediately need a private key, consider using the GenerateDataKeyPairWithoutPlaintext operation. GenerateDataKeyPairWithoutPlaintext returns a plaintext public key and an encrypted private key, but omits the plaintext private key that you need only to decrypt ciphertext or sign a message. Later, when you need to decrypt the data or sign a message, use the Decrypt operation to decrypt the encrypted private key in the data key pair.

GenerateDataKeyPair returns a unique data key pair for each request. The bytes in the keys are random; they are not related to the caller or the KMS key that is used to encrypt the private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified in RFC 5280. The private key is a DER-encoded PKCS8 PrivateKeyInfo, as specified in RFC 5958.

GenerateDataKeyPair also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateDataKeyPair for an Amazon Web Services Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. GenerateDataKeyPair returns the public data key and a copy of the private data key encrypted under the specified KMS key, as usual. But instead of a plaintext copy of the private data key (PrivateKeyPlaintext), the response includes a copy of the private data key encrypted under the public key from the attestation document (CiphertextForRecipient). For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide..

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyPair (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPairWithoutPlaintext

• GenerateDataKeyWithoutPlaintext

Returns a unique asymmetric data key pair for use outside of KMS. This operation returns a plaintext public key and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. Unlike GenerateDataKeyPair, this operation does not return a plaintext private key. The bytes in the keys are random; they are not related to the caller or to the KMS key that is used to encrypt the private key.

You can use the public key that GenerateDataKeyPairWithoutPlaintext returns to encrypt data or verify a signature outside of KMS. Then, store the encrypted private key with the data. When you are ready to decrypt data or sign a message, you can use the Decrypt operation to decrypt the encrypted private key.

To generate a data key pair, you must specify a symmetric encryption KMS key to encrypt the private key in a data key pair. You cannot use an asymmetric KMS key or a KMS key in a custom key store. To get the type and origin of your KMS key, use the DescribeKey operation.

Use the KeyPairSpec parameter to choose an RSA or Elliptic Curve (ECC) data key pair. In China Regions, you can also choose an SM2 data key pair. KMS recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs for either encryption or signing, but not both. However, KMS cannot enforce any restrictions on the use of data key pairs outside of KMS.

GenerateDataKeyPairWithoutPlaintext returns a unique data key pair for each request. The bytes in the key are not related to the caller or KMS key that is used to encrypt the private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified in RFC 5280.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyPairWithoutPlaintext (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyWithoutPlaintext

Returns a unique asymmetric data key pair for use outside of KMS. This operation returns a plaintext public key and a copy of the private key that is encrypted under the symmetric encryption KMS key you specify. Unlike GenerateDataKeyPair, this operation does not return a plaintext private key. The bytes in the keys are random; they are not related to the caller or to the KMS key that is used to encrypt the private key.

You can use the public key that GenerateDataKeyPairWithoutPlaintext returns to encrypt data or verify a signature outside of KMS. Then, store the encrypted private key with the data. When you are ready to decrypt data or sign a message, you can use the Decrypt operation to decrypt the encrypted private key.

To generate a data key pair, you must specify a symmetric encryption KMS key to encrypt the private key in a data key pair. You cannot use an asymmetric KMS key or a KMS key in a custom key store. To get the type and origin of your KMS key, use the DescribeKey operation.

Use the KeyPairSpec parameter to choose an RSA or Elliptic Curve (ECC) data key pair. In China Regions, you can also choose an SM2 data key pair. KMS recommends that you use ECC key pairs for signing, and use RSA and SM2 key pairs for either encryption or signing, but not both. However, KMS cannot enforce any restrictions on the use of data key pairs outside of KMS.

GenerateDataKeyPairWithoutPlaintext returns a unique data key pair for each request. The bytes in the key are not related to the caller or KMS key that is used to encrypt the private key. The public key is a DER-encoded X.509 SubjectPublicKeyInfo, as specified in RFC 5280.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyPairWithoutPlaintext (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyWithoutPlaintext

Returns a unique symmetric data key for use outside of KMS. This operation returns a data key that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the key are random; they are not related to the caller or to the KMS key.

GenerateDataKeyWithoutPlaintext is identical to the GenerateDataKey operation except that it does not return a plaintext copy of the data key.

This operation is useful for systems that need to encrypt data at some point, but not immediately. When you need to encrypt the data, you call the Decrypt operation on the encrypted copy of the key.

It’s also useful in distributed systems with different levels of trust. For example, you might store encrypted data in containers. One component of your system creates new containers and stores an encrypted data key with each container. Then, a different component puts the data into the containers. That component first decrypts the data key, uses the plaintext data key to encrypt data, puts the encrypted data into the container, and then destroys the plaintext data key. In this system, the component that creates the containers never sees the plaintext data key.

To request an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operations.

To generate a data key, you must specify the symmetric encryption KMS key that is used to encrypt the data key. You cannot use an asymmetric KMS key or a key in a custom key store to generate a data key. To get the type of your KMS key, use the DescribeKey operation.

You must also specify the length of the data key. Use either the KeySpec or NumberOfBytes parameters (but not both). For 128-bit and 256-bit data keys, use the KeySpec parameter.

To generate an SM4 data key (China Regions only), specify a KeySpec value of AES_128 or NumberOfBytes value of 16. The symmetric encryption key used in China Regions to encrypt your data key is an SM4 encryption key.

If the operation succeeds, you will find the encrypted copy of the data key in the CiphertextBlob field.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyWithoutPlaintext (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyPairWithoutPlaintext

Returns a unique symmetric data key for use outside of KMS. This operation returns a data key that is encrypted under a symmetric encryption KMS key that you specify. The bytes in the key are random; they are not related to the caller or to the KMS key.

GenerateDataKeyWithoutPlaintext is identical to the GenerateDataKey operation except that it does not return a plaintext copy of the data key.

This operation is useful for systems that need to encrypt data at some point, but not immediately. When you need to encrypt the data, you call the Decrypt operation on the encrypted copy of the key.

It’s also useful in distributed systems with different levels of trust. For example, you might store encrypted data in containers. One component of your system creates new containers and stores an encrypted data key with each container. Then, a different component puts the data into the containers. That component first decrypts the data key, uses the plaintext data key to encrypt data, puts the encrypted data into the container, and then destroys the plaintext data key. In this system, the component that creates the containers never sees the plaintext data key.

To request an asymmetric data key pair, use the GenerateDataKeyPair or GenerateDataKeyPairWithoutPlaintext operations.

To generate a data key, you must specify the symmetric encryption KMS key that is used to encrypt the data key. You cannot use an asymmetric KMS key or a key in a custom key store to generate a data key. To get the type of your KMS key, use the DescribeKey operation.

You must also specify the length of the data key. Use either the KeySpec or NumberOfBytes parameters (but not both). For 128-bit and 256-bit data keys, use the KeySpec parameter.

To generate an SM4 data key (China Regions only), specify a KeySpec value of AES_128 or NumberOfBytes value of 16. The symmetric encryption key used in China Regions to encrypt your data key is an SM4 encryption key.

If the operation succeeds, you will find the encrypted copy of the data key in the CiphertextBlob field.

You can use an optional encryption context to add additional security to the encryption operation. If you specify an EncryptionContext, you must specify the same encryption context (a case-sensitive exact match) when decrypting the encrypted data key. Otherwise, the request to decrypt fails with an InvalidCiphertextException. For more information, see Encryption Context in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateDataKeyWithoutPlaintext (key policy)

Related operations:

• Decrypt

• Encrypt

• GenerateDataKey

• GenerateDataKeyPair

• GenerateDataKeyPairWithoutPlaintext

Generates a hash-based message authentication code (HMAC) for a message using an HMAC KMS key and a MAC algorithm that the key supports. HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104.

You can use value that GenerateMac returns in the VerifyMac operation to demonstrate that the original message has not changed. Also, because a secret key is used to create the hash, you can verify that the party that generated the hash has the required secret key. You can also use the raw result to implement HMAC-based algorithms such as key derivation functions. This operation is part of KMS support for HMAC KMS keys. For details, see HMAC keys in KMS in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateMac (key policy)

Related operations: VerifyMac

Generates a hash-based message authentication code (HMAC) for a message using an HMAC KMS key and a MAC algorithm that the key supports. HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104.

You can use value that GenerateMac returns in the VerifyMac operation to demonstrate that the original message has not changed. Also, because a secret key is used to create the hash, you can verify that the party that generated the hash has the required secret key. You can also use the raw result to implement HMAC-based algorithms such as key derivation functions. This operation is part of KMS support for HMAC KMS keys. For details, see HMAC keys in KMS in the Key Management Service Developer Guide.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

Cross-account use: Yes. To perform this operation with a KMS key in a different Amazon Web Services account, specify the key ARN or alias ARN in the value of the KeyId parameter.

Required permissions: kms:GenerateMac (key policy)

Related operations: VerifyMac

Returns a random byte string that is cryptographically secure.

You must use the NumberOfBytes parameter to specify the length of the random byte string. There is no default value for string length.

By default, the random byte string is generated in KMS. To generate the byte string in the CloudHSM cluster associated with an CloudHSM key store, use the CustomKeyStoreId parameter.

GenerateRandom also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateRandom for a Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. Instead of plaintext bytes, the response includes the plaintext bytes encrypted under the public key from the attestation document (CiphertextForRecipient).For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide.

For more information about entropy and random number generation, see Key Management Service Cryptographic Details.

Cross-account use: Not applicable. GenerateRandom does not use any account-specific resources, such as KMS keys.

Required permissions: kms:GenerateRandom (IAM policy)

Returns a random byte string that is cryptographically secure.

You must use the NumberOfBytes parameter to specify the length of the random byte string. There is no default value for string length.

By default, the random byte string is generated in KMS. To generate the byte string in the CloudHSM cluster associated with an CloudHSM key store, use the CustomKeyStoreId parameter.

GenerateRandom also supports Amazon Web Services Nitro Enclaves, which provide an isolated compute environment in Amazon EC2. To call GenerateRandom for a Nitro enclave, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK. Use the Recipient parameter to provide the attestation document for the enclave. Instead of plaintext bytes, the response includes the plaintext bytes encrypted under the public key from the attestation document (CiphertextForRecipient).For information about the interaction between KMS and Amazon Web Services Nitro Enclaves, see How Amazon Web Services Nitro Enclaves uses KMS in the Key Management Service Developer Guide.

For more information about entropy and random number generation, see Key Management Service Cryptographic Details.

Cross-account use: Not applicable. GenerateRandom does not use any account-specific resources, such as KMS keys.

Required permissions: kms:GenerateRandom (IAM policy)

Gets a key policy attached to the specified KMS key.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:GetKeyPolicy (key policy)

Related operations: PutKeyPolicy

Gets a key policy attached to the specified KMS key.

Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account.

Required permissions: kms:GetKeyPolicy (key policy)

Related operations: PutKeyPolicy

Gets a Boolean value that indicates whether automatic rotation of the key material is enabled for the specified KMS key.

When you enable automatic rotation for customer managed KMS keys, KMS rotates the key material of the KMS key one year (approximately 365 days) from the enable date and every year thereafter. You can monitor rotation of the key material for your KMS keys in CloudTrail and Amazon CloudWatch.

Automatic key rotation is supported only on symmetric encryption KMS keys. You cannot enable automatic rotation of asymmetric KMS keys, HMAC KMS keys, KMS keys with imported key material, or KMS keys in a custom key store. To enable or disable automatic rotation of a set of related multi-Region keys, set the property on the primary key..

You can enable (EnableKeyRotation) and disable automatic rotation (DisableKeyRotation) of the key material in customer managed KMS keys. Key material rotation of Amazon Web Services managed KMS keys is not configurable. KMS always rotates the key material in Amazon Web Services managed KMS keys every year. The key rotation status for Amazon Web Services managed KMS keys is always true.

The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.

• Disabled: The key rotation status does not change when you disable a KMS key. However, while the KMS key is disabled, KMS does not rotate the key material. When you re-enable the KMS key, rotation resumes. If the key material in the re-enabled KMS key hasn’t been rotated in one year, KMS rotates it immediately, and every year thereafter. If it’s been less than a year since the key material in the re-enabled KMS key was rotated, the KMS key resumes its prior rotation schedule.

• Pending deletion: While a KMS key is pending deletion, its key rotation status is false and KMS does not rotate the key material. If you cancel the deletion, the original key rotation status returns to true.

Cross-account use: Yes. To perform this operation on a KMS key in a different Amazon Web Services account, specify the key ARN in the value of the KeyId parameter.

Required permissions: kms:GetKeyRotationStatus (key policy)

Related operations:

• DisableKeyRotation

• EnableKeyRotation