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AWS Key Management Service

AWS Key Management Service (AWS KMS) is an encryption and key management web service. This guide describes the AWS KMS operations that you can call programmatically. For general information about AWS KMS, see the AWS Key Management Service Developer Guide .

AWS provides SDKs that consist of libraries and sample code for various programming languages and platforms (Java, Ruby, .Net, macOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to AWS KMS and other AWS services. For example, the SDKs take care of tasks such as signing requests (see below), managing errors, and retrying requests automatically. For more information about the AWS SDKs, including how to download and install them, see Tools for Amazon Web Services.

We recommend that you use the AWS SDKs to make programmatic API calls to AWS KMS.

Clients must support TLS (Transport Layer Security) 1.0. We recommend TLS 1.2. Clients must also support cipher suites with Perfect Forward Secrecy (PFS) such as Ephemeral Diffie-Hellman (DHE) or Elliptic Curve Ephemeral Diffie-Hellman (ECDHE). Most modern systems such as Java 7 and later support these modes.

Signing Requests

Requests must be signed by using an access key ID and a secret access key. We strongly recommend that you do not use your AWS account (root) access key ID and secret key for everyday work with AWS KMS. Instead, use the access key ID and secret access key for an IAM user. You can also use the AWS Security Token Service to generate temporary security credentials that you can use to sign requests.

All AWS KMS operations require Signature Version 4.

Logging API Requests

AWS KMS supports AWS CloudTrail, a service that logs AWS API calls and related events for your AWS account and delivers them to an Amazon S3 bucket that you specify. By using the information collected by CloudTrail, you can determine what requests were made to AWS KMS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the AWS CloudTrail User Guide.

Additional Resources

For more information about credentials and request signing, see the following:

Commonly Used API Operations

Of the API operations discussed in this guide, the following will prove the most useful for most applications. You will likely perform operations other than these, such as creating keys and assigning policies, by using the console.

If you’re using the service, you’re probably looking for KmsClient and Kms.


Contains information about an alias.

Contains information about each custom key store in the custom key store list.

Use this structure to allow cryptographic operations in the grant only when the operation request includes the specified encryption context.

AWS KMS applies the grant constraints only to cryptographic operations that support an encryption context, that is, all cryptographic operations with a symmetric CMK. Grant constraints are not applied to operations that do not support an encryption context, such as cryptographic operations with asymmetric CMKs and management operations, such as DescribeKey or RetireGrant.

In a cryptographic operation, the encryption context in the decryption operation must be an exact, case-sensitive match for the keys and values in the encryption context of the encryption operation. Only the order of the pairs can vary.

However, in a grant constraint, the key in each key-value pair is not case sensitive, but the value is case sensitive.

To avoid confusion, do not use multiple encryption context pairs that differ only by case. To require a fully case-sensitive encryption context, use the kms:EncryptionContext: and kms:EncryptionContextKeys conditions in an IAM or key policy. For details, see kms:EncryptionContext: in the AWS Key Management Service Developer Guide .

Contains information about a grant.

Contains information about each entry in the key list.

Contains metadata about a customer master key (CMK).

This data type is used as a response element for the CreateKey and DescribeKey operations.

A client for the KMS API.

Describes the configuration of this multi-Region CMK. This field appears only when the CMK is a primary or replica of a multi-Region CMK.

For more information about any listed CMK, use the DescribeKey operation.

Describes the primary or replica key in a multi-Region key.

A key-value pair. A tag consists of a tag key and a tag value. Tag keys and tag values are both required, but tag values can be empty (null) strings.

For information about the rules that apply to tag keys and tag values, see User-Defined Tag Restrictions in the AWS Billing and Cost Management User Guide.


Errors returned by CancelKeyDeletion

Errors returned by ConnectCustomKeyStore

Errors returned by CreateAlias

Errors returned by CreateCustomKeyStore

Errors returned by CreateGrant

Errors returned by CreateKey

Errors returned by Decrypt

Errors returned by DeleteAlias

Errors returned by DeleteCustomKeyStore

Errors returned by DeleteImportedKeyMaterial

Errors returned by DescribeCustomKeyStores

Errors returned by DescribeKey

Errors returned by DisableKey

Errors returned by DisableKeyRotation

Errors returned by DisconnectCustomKeyStore

Errors returned by EnableKey

Errors returned by EnableKeyRotation

Errors returned by Encrypt

Errors returned by GenerateDataKey

Errors returned by GenerateDataKeyPair

Errors returned by GenerateDataKeyPairWithoutPlaintext

Errors returned by GenerateDataKeyWithoutPlaintext

Errors returned by GenerateRandom

Errors returned by GetKeyPolicy

Errors returned by GetKeyRotationStatus

Errors returned by GetParametersForImport

Errors returned by GetPublicKey

Errors returned by ImportKeyMaterial

Errors returned by ListAliases

Errors returned by ListGrants

Errors returned by ListKeyPolicies

Errors returned by ListKeys

Errors returned by ListResourceTags

Errors returned by ListRetirableGrants

Errors returned by PutKeyPolicy

Errors returned by ReEncrypt

Errors returned by ReplicateKey

Errors returned by RetireGrant

Errors returned by RevokeGrant

Errors returned by ScheduleKeyDeletion

Errors returned by Sign

Errors returned by TagResource

Errors returned by UntagResource

Errors returned by UpdateAlias

Errors returned by UpdateCustomKeyStore

Errors returned by UpdateKeyDescription

Errors returned by UpdatePrimaryRegion

Errors returned by Verify


Trait representing the capabilities of the KMS API. KMS clients implement this trait.