AWS Key Management Service (KMS)
Key Management Service
Key Management Service (KMS) is an encryption and key management web service. This guide describes the KMS operations that you can call programmatically. For general information about KMS, see the Key Management Service Developer Guide .
KMS has replaced the term customer master key (CMK) with KMS key and KMS key. The concept has not changed. To prevent breaking changes, KMS is keeping some variations of this term.
Amazon Web Services 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 KMS and other Amazon Web Services 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 Amazon Web Services SDKs, including how to download and install them, see Tools for Amazon Web Services.
We recommend that you use the Amazon Web Services SDKs to make programmatic API calls to KMS.
If you need to use FIPS 140-2 validated cryptographic modules when communicating with Amazon Web Services, use the FIPS endpoint in your preferred Amazon Web Services Region. For more information about the available FIPS endpoints, see Service endpoints in the Key Management Service topic of the Amazon Web Services General Reference.
All KMS API calls must be signed and be transmitted using Transport Layer Security (TLS). KMS recommends you always use the latest supported TLS version. 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 using an access key ID and a secret access key. We strongly recommend that you do not use your Amazon Web Services account root access key ID and secret access key for everyday work. You can use the access key ID and secret access key for an IAM user or you can use the Security Token Service (STS) to generate temporary security credentials and use those to sign requests.
All KMS requests must be signed with Signature Version 4.
Logging API Requests
KMS supports CloudTrail, a service that logs Amazon Web Services API calls and related events for your Amazon Web Services 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 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 CloudTrail User Guide.
Additional Resources
For more information about credentials and request signing, see the following:
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Amazon Web Services Security Credentials - This topic provides general information about the types of credentials used to access Amazon Web Services.
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Temporary Security Credentials - This section of the IAM User Guide describes how to create and use temporary security credentials.
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Signature Version 4 Signing Process - This set of topics walks you through the process of signing a request using an access key ID and a secret access key.
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.
Operations
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 ...
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 s...
Creates a friendly name for a KMS key. Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guid...
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 perform...
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 (DescribeK...
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...
Decrypts ciphertext that was encrypted by a KMS key using any of the following operations: Encrypt GenerateDataKey GenerateDataKeyPair GenerateDataKeyWithoutPlaintext GenerateDataKeyPairWithoutPlai...
Deletes the specified alias. Adding, deleting, or updating an alias can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide. Because...
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 af...
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...
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 w...
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...
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...
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...
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 exte...
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 detai...
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 KM...
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 arb...
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 specif...
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 s...
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 ke...
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 rando...
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 ...
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....
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:GetK...
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 rotate...
Returns the items you need to import key material into a symmetric encryption KMS key. For more information about importing key material into KMS, see Importing key material in the Key Management S...
Returns the public key of an asymmetric KMS key. Unlike the private key of a asymmetric KMS key, which never leaves KMS unencrypted, callers with kms:GetPublicKey permission can download the public...
Imports key material into an existing symmetric encryption KMS key that was created without key material. After you successfully import key material into a KMS key, you can reimport the same key ma...
Gets a list of aliases in the caller's Amazon Web Services account and region. For more information about aliases, see CreateAlias. By default, the ListAliases operation returns all aliases in the ...
Gets a list of all grants for the specified KMS key. You must specify the KMS key in all requests. You can filter the grant list by grant ID or grantee principal. For detailed information about gra...
Gets the names of the key policies that are attached to a KMS key. This operation is designed to get policy names that you can use in a GetKeyPolicy operation. However, the only valid policy name i...
Gets a list of all KMS keys in the caller's Amazon Web Services account and Region. Cross-account use: No. You cannot perform this operation on a KMS key in a different Amazon Web Services account....
Returns all tags on the specified KMS key. For general information about tags, including the format and syntax, see Tagging Amazon Web Services resources in the Amazon Web Services General Referenc...
Returns information about all grants in the Amazon Web Services account and Region that have the specified retiring principal. You can specify any principal in your Amazon Web Services account. The...
Attaches a key policy to the specified KMS key. For more information about key policies, see Key Policies in the Key Management Service Developer Guide. For help writing and formatting a JSON polic...
Decrypts ciphertext and then reencrypts it entirely within KMS. You can use this operation to change the KMS key under which data is encrypted, such as when you manually rotate a KMS key or change ...
Replicates a multi-Region key into the specified Region. This operation creates a multi-Region replica key based on a multi-Region primary key in a different Region of the same Amazon Web Services ...
Deletes a grant. Typically, you retire a grant when you no longer need its permissions. To identify the grant to retire, use a grant token, or both the grant ID and a key identifier (key ID or key ...
Deletes the specified grant. You revoke a grant to terminate the permissions that the grant allows. For more information, see Retiring and revoking grants in the Key Management Service Developer Gu...
Schedules the deletion of a KMS key. By default, KMS applies a waiting period of 30 days, but you can specify a waiting period of 7-30 days. When this operation is successful, the key state of the ...
Creates a digital signature for a message or message digest by using the private key in an asymmetric signing KMS key. To verify the signature, use the Verify operation, or use the public key in th...
Adds or edits tags on a customer managed key. Tagging or untagging a KMS key can allow or deny permission to the KMS key. For details, see ABAC for KMS in the Key Management Service Developer Guide...
Deletes tags from a customer managed key. To delete a tag, specify the tag key and the KMS key. Tagging or untagging a KMS key can allow or deny permission to the KMS key. For details, see ABAC for...
Associates an existing KMS alias with a different KMS key. Each alias is associated with only one KMS key at a time, although a KMS key can have multiple aliases. The alias and the KMS key must be ...
Changes the properties of a custom key store. You can use this operation to change the properties of an CloudHSM key store or an external key store. Use the required CustomKeyStoreId parameter to i...
Updates the description of a KMS key. To see the description of a KMS key, use DescribeKey. The KMS key that you use for this operation must be in a compatible key state. For details, see Key state...
Changes the primary key of a multi-Region key. This operation changes the replica key in the specified Region to a primary key and changes the former primary key to a replica key. For example, supp...
Verifies a digital signature that was generated by the Sign operation. Verification confirms that an authorized user signed the message with the specified KMS key and signing algorithm, and the mes...
Verifies the hash-based message authentication code (HMAC) for a specified message, HMAC KMS key, and MAC algorithm. To verify the HMAC, VerifyMac computes an HMAC using the message, HMAC KMS key, ...
