AWS API Changes

2023/07/05 - AWS Key Management Service - 14 updated api methods

Changes Added Dry Run Feature to cryptographic and cross-account mutating KMS APIs (14 in all). This feature allows users to test their permissions and parameters before making the actual API call.

CreateGrant (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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

See also: AWS API Documentation

Request Syntax

client.create_grant(
    KeyId='string',
    GranteePrincipal='string',
    RetiringPrincipal='string',
    Operations=[
        'Decrypt'|'Encrypt'|'GenerateDataKey'|'GenerateDataKeyWithoutPlaintext'|'ReEncryptFrom'|'ReEncryptTo'|'Sign'|'Verify'|'GetPublicKey'|'CreateGrant'|'RetireGrant'|'DescribeKey'|'GenerateDataKeyPair'|'GenerateDataKeyPairWithoutPlaintext'|'GenerateMac'|'VerifyMac',
    ],
    Constraints={
        'EncryptionContextSubset': {
            'string': 'string'
        },
        'EncryptionContextEquals': {
            'string': 'string'
        }
    },
    GrantTokens=[
        'string',
    ],
    Name='string',
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

Identifies the KMS key for the grant. The grant gives principals permission to use this KMS key.

Specify the key ID or key ARN of the KMS key. To specify a KMS key in a different Amazon Web Services account, you must use the key ARN.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey .

type GranteePrincipal

string

param GranteePrincipal

[REQUIRED]

The identity that gets the permissions specified in the grant.

To specify the grantee principal, use the Amazon Resource Name (ARN) of an Amazon Web Services principal. Valid principals include Amazon Web Services accounts, IAM users, IAM roles, federated users, and assumed role users. For help with the ARN syntax for a principal, see IAM ARNs in the * Identity and Access Management User Guide * .

type RetiringPrincipal

string

param RetiringPrincipal

The principal that has permission to use the RetireGrant operation to retire the grant.

To specify the principal, use the Amazon Resource Name (ARN) of an Amazon Web Services principal. Valid principals include Amazon Web Services accounts, IAM users, IAM roles, federated users, and assumed role users. For help with the ARN syntax for a principal, see IAM ARNs in the * Identity and Access Management User Guide * .

The grant determines the retiring principal. Other principals might have permission to retire the grant or revoke the grant. For details, see RevokeGrant and Retiring and revoking grants in the Key Management Service Developer Guide .

type Operations

list

param Operations

[REQUIRED]

A list of operations that the grant permits.

This list must include only operations that are permitted in a grant. Also, the operation must be supported on the KMS key. For example, you cannot create a grant for a symmetric encryption KMS key that allows the Sign operation, or a grant for an asymmetric KMS key that allows the GenerateDataKey operation. If you try, KMS returns a ValidationError exception. For details, see Grant operations in the Key Management Service Developer Guide .

(string) --

type Constraints

dict

param Constraints

Specifies a grant constraint.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

KMS supports the EncryptionContextEquals and EncryptionContextSubset grant constraints, which allow the permissions in the grant only when the encryption context in the request matches (EncryptionContextEquals ) or includes (EncryptionContextSubset ) the encryption context specified in the constraint.

The encryption context grant constraints are supported only on grant operations that include an EncryptionContext parameter, such as cryptographic operations on symmetric encryption KMS keys. Grants with grant constraints can include the DescribeKey and RetireGrant operations, but the constraint doesn't apply to these operations. If a grant with a grant constraint includes the CreateGrant operation, the constraint requires that any grants created with the CreateGrant permission have an equally strict or stricter encryption context constraint.

You cannot use an encryption context grant constraint for cryptographic operations with asymmetric KMS keys or HMAC KMS keys. Operations with these keys don't support an encryption context.

Each constraint value can include up to 8 encryption context pairs. The encryption context value in each constraint cannot exceed 384 characters. For information about grant constraints, see Using grant constraints in the Key Management Service Developer Guide . For more information about encryption context, see Encryption context in the * Key Management Service Developer Guide * .

EncryptionContextSubset (dict) --

A list of key-value pairs that must be included in the encryption context of the cryptographic operation request. The grant allows the cryptographic operation only when the encryption context in the request includes the key-value pairs specified in this constraint, although it can include additional key-value pairs.
- (string) --
  - (string) --
EncryptionContextEquals (dict) --

A list of key-value pairs that must match the encryption context in the cryptographic operation request. The grant allows the operation only when the encryption context in the request is the same as the encryption context specified in this constraint.
- (string) --
  - (string) --

type GrantTokens

list

param GrantTokens

A list of grant tokens.

Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency . For more information, see Grant token and Using a grant token in the Key Management Service Developer Guide .

(string) --

type Name

string

param Name

A friendly name for the grant. Use this value to prevent the unintended creation of duplicate grants when retrying this request.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

When this value is absent, all CreateGrant requests result in a new grant with a unique GrantId even if all the supplied parameters are identical. This can result in unintended duplicates when you retry the CreateGrant request.

When this value is present, you can retry a CreateGrant request with identical parameters; if the grant already exists, the original GrantId is returned without creating a new grant. Note that the returned grant token is unique with every CreateGrant request, even when a duplicate GrantId is returned. All grant tokens for the same grant ID can be used interchangeably.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'GrantToken': 'string',
    'GrantId': 'string'
}

Response Structure

(dict) --
- GrantToken (string) --
  
  The grant token.
  
  Use a grant token when your permission to call this operation comes from a new grant that has not yet achieved eventual consistency . For more information, see Grant token and Using a grant token in the Key Management Service Developer Guide .
- GrantId (string) --
  
  The unique identifier for the grant.
  
  You can use the GrantId in a ListGrants , RetireGrant , or RevokeGrant operation.

Decrypt (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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

See also: AWS API Documentation

Request Syntax

client.decrypt(
    CiphertextBlob=b'bytes',
    EncryptionContext={
        'string': 'string'
    },
    GrantTokens=[
        'string',
    ],
    KeyId='string',
    EncryptionAlgorithm='SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    Recipient={
        'KeyEncryptionAlgorithm': 'RSAES_OAEP_SHA_256',
        'AttestationDocument': b'bytes'
    },
    DryRun=True|False
)

type CiphertextBlob

bytes

param CiphertextBlob

[REQUIRED]

Ciphertext to be decrypted. The blob includes metadata.

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context to use when decrypting the data. An encryption context is valid only for cryptographic operations with a symmetric encryption KMS key. The standard asymmetric encryption algorithms and HMAC algorithms that KMS uses do not support an encryption context.

An encryption context is a collection of non-secret key-value pairs that represent additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is supported only on operations with symmetric encryption KMS keys. On operations with symmetric encryption KMS keys, an encryption context is optional, but it is strongly recommended.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type KeyId

string

param KeyId

Specifies the KMS key that KMS uses to decrypt the ciphertext.

Enter a key ID of the KMS key that was used to encrypt the ciphertext. If you identify a different KMS key, the Decrypt operation throws an IncorrectKeyException .

This parameter is required only when the ciphertext was encrypted under an asymmetric KMS key. If you used a symmetric encryption KMS key, KMS can get the KMS key from metadata that it adds to the symmetric ciphertext blob. However, it is always recommended as a best practice. This practice ensures that you use the KMS key that you intend.

To specify a KMS key, use its key ID, key ARN, alias name, or alias ARN. When using an alias name, prefix it with "alias/" . To specify a KMS key in a different Amazon Web Services account, you must use the key ARN or alias ARN.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type EncryptionAlgorithm

string

param EncryptionAlgorithm

Specifies the encryption algorithm that will be used to decrypt the ciphertext. Specify the same algorithm that was used to encrypt the data. If you specify a different algorithm, the Decrypt operation fails.

This parameter is required only when the ciphertext was encrypted under an asymmetric KMS key. The default value, SYMMETRIC_DEFAULT , represents the only supported algorithm that is valid for symmetric encryption KMS keys.

type Recipient

dict

param Recipient

A signed attestation document from an Amazon Web Services Nitro enclave and the encryption algorithm to use with the enclave's public key. The only valid encryption algorithm is RSAES_OAEP_SHA_256 .

This parameter only supports attestation documents for Amazon Web Services Nitro Enclaves. To include this parameter, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK.

When you use this parameter, instead of returning the plaintext data, KMS encrypts the plaintext data with the public key in the attestation document, and returns the resulting ciphertext in the CiphertextForRecipient field in the response. This ciphertext can be decrypted only with the private key in the enclave. The Plaintext field in the response is null or empty.

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 .

KeyEncryptionAlgorithm (string) --

The encryption algorithm that KMS should use with the public key for an Amazon Web Services Nitro Enclave to encrypt plaintext values for the response. The only valid value is RSAES_OAEP_SHA_256 .
AttestationDocument (bytes) --

The attestation document for an Amazon Web Services Nitro Enclave. This document includes the enclave's public key.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'KeyId': 'string',
    'Plaintext': b'bytes',
    'EncryptionAlgorithm': 'SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    'CiphertextForRecipient': b'bytes'
}

Response Structure

(dict) --
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that was used to decrypt the ciphertext.
- Plaintext (bytes) --
  
  Decrypted plaintext data. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
  
  If the response includes the CiphertextForRecipient field, the Plaintext field is null or empty.
- EncryptionAlgorithm (string) --
  
  The encryption algorithm that was used to decrypt the ciphertext.
- CiphertextForRecipient (bytes) --
  
  The plaintext data encrypted with the public key in the attestation document.
  
  This field is included in the response only when the Recipient parameter in the request includes a valid attestation document from an Amazon Web Services Nitro enclave. 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 .

Encrypt (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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.

Warning

You are not required to supply the key ID and encryption algorithm when you decrypt with symmetric encryption KMS keys because KMS stores this information in the ciphertext blob. KMS cannot store metadata in ciphertext generated with asymmetric keys. The standard format for asymmetric key ciphertext does not include configurable fields.

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

See also: AWS API Documentation

Request Syntax

client.encrypt(
    KeyId='string',
    Plaintext=b'bytes',
    EncryptionContext={
        'string': 'string'
    },
    GrantTokens=[
        'string',
    ],
    EncryptionAlgorithm='SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

Identifies the KMS key to use in the encryption operation. The KMS key must have a KeyUsage of ENCRYPT_DECRYPT . To find the KeyUsage of a KMS key, use the DescribeKey operation.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type Plaintext

bytes

param Plaintext

[REQUIRED]

Data to be encrypted.

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context that will be used to encrypt the data. An encryption context is valid only for cryptographic operations with a symmetric encryption KMS key. The standard asymmetric encryption algorithms and HMAC algorithms that KMS uses do not support an encryption context.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type EncryptionAlgorithm

string

param EncryptionAlgorithm

Specifies the encryption algorithm that KMS will use to encrypt the plaintext message. The algorithm must be compatible with the KMS key that you specify.

This parameter is required only for asymmetric KMS keys. The default value, SYMMETRIC_DEFAULT , is the algorithm used for symmetric encryption KMS keys. If you are using an asymmetric KMS key, we recommend RSAES_OAEP_SHA_256.

The SM2PKE algorithm is only available in China Regions.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'CiphertextBlob': b'bytes',
    'KeyId': 'string',
    'EncryptionAlgorithm': 'SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE'
}

Response Structure

(dict) --
- CiphertextBlob (bytes) --
  
  The encrypted plaintext. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that was used to encrypt the plaintext.
- EncryptionAlgorithm (string) --
  
  The encryption algorithm that was used to encrypt the plaintext.

GenerateDataKey (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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:

Use the GenerateDataKey operation to get a data key.
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.
Store the encrypted data key (in the CiphertextBlob field of the response) with the encrypted data.

To decrypt data outside of KMS:

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

See also: AWS API Documentation

Request Syntax

client.generate_data_key(
    KeyId='string',
    EncryptionContext={
        'string': 'string'
    },
    NumberOfBytes=123,
    KeySpec='AES_256'|'AES_128',
    GrantTokens=[
        'string',
    ],
    Recipient={
        'KeyEncryptionAlgorithm': 'RSAES_OAEP_SHA_256',
        'AttestationDocument': b'bytes'
    },
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

Specifies the symmetric encryption KMS key that encrypts the data key. You cannot specify 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.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context that will be used when encrypting the data key.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type NumberOfBytes

integer

param NumberOfBytes

Specifies the length of the data key in bytes. For example, use the value 64 to generate a 512-bit data key (64 bytes is 512 bits). For 128-bit (16-byte) and 256-bit (32-byte) data keys, use the KeySpec parameter.

You must specify either the KeySpec or the NumberOfBytes parameter (but not both) in every GenerateDataKey request.

type KeySpec

string

param KeySpec

Specifies the length of the data key. Use AES_128 to generate a 128-bit symmetric key, or AES_256 to generate a 256-bit symmetric key.

You must specify either the KeySpec or the NumberOfBytes parameter (but not both) in every GenerateDataKey request.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type Recipient

dict

param Recipient

A signed attestation document from an Amazon Web Services Nitro enclave and the encryption algorithm to use with the enclave's public key. The only valid encryption algorithm is RSAES_OAEP_SHA_256 .

This parameter only supports attestation documents for Amazon Web Services Nitro Enclaves. To include this parameter, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK.

When you use this parameter, instead of returning the plaintext data key, KMS encrypts the plaintext data key under the public key in the attestation document, and returns the resulting ciphertext in the CiphertextForRecipient field in the response. This ciphertext can be decrypted only with the private key in the enclave. The CiphertextBlob field in the response contains a copy of the data key encrypted under the KMS key specified by the KeyId parameter. The Plaintext field in the response is null or empty.

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 .

KeyEncryptionAlgorithm (string) --

The encryption algorithm that KMS should use with the public key for an Amazon Web Services Nitro Enclave to encrypt plaintext values for the response. The only valid value is RSAES_OAEP_SHA_256 .
AttestationDocument (bytes) --

The attestation document for an Amazon Web Services Nitro Enclave. This document includes the enclave's public key.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'CiphertextBlob': b'bytes',
    'Plaintext': b'bytes',
    'KeyId': 'string',
    'CiphertextForRecipient': b'bytes'
}

Response Structure

(dict) --
- CiphertextBlob (bytes) --
  
  The encrypted copy of the data key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- Plaintext (bytes) --
  
  The plaintext data key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded. Use this data key to encrypt your data outside of KMS. Then, remove it from memory as soon as possible.
  
  If the response includes the CiphertextForRecipient field, the Plaintext field is null or empty.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that encrypted the data key.
- CiphertextForRecipient (bytes) --
  
  The plaintext data key encrypted with the public key from the Nitro enclave. This ciphertext can be decrypted only by using a private key in the Nitro enclave.
  
  This field is included in the response only when the Recipient parameter in the request includes a valid attestation document from an Amazon Web Services Nitro enclave. 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 .

GenerateDataKeyPair (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 ..

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

See also: AWS API Documentation

Request Syntax

client.generate_data_key_pair(
    EncryptionContext={
        'string': 'string'
    },
    KeyId='string',
    KeyPairSpec='RSA_2048'|'RSA_3072'|'RSA_4096'|'ECC_NIST_P256'|'ECC_NIST_P384'|'ECC_NIST_P521'|'ECC_SECG_P256K1'|'SM2',
    GrantTokens=[
        'string',
    ],
    Recipient={
        'KeyEncryptionAlgorithm': 'RSAES_OAEP_SHA_256',
        'AttestationDocument': b'bytes'
    },
    DryRun=True|False
)

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context that will be used when encrypting the private key in the data key pair.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type KeyId

string

param KeyId

[REQUIRED]

Specifies the symmetric encryption KMS key that encrypts the private key in the data key pair. You cannot specify 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.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type KeyPairSpec

string

param KeyPairSpec

[REQUIRED]

Determines the type of data key pair that is generated.

The KMS rule that restricts the use of asymmetric RSA and SM2 KMS keys to encrypt and decrypt or to sign and verify (but not both), and the rule that permits you to use ECC KMS keys only to sign and verify, are not effective on data key pairs, which are used outside of KMS. The SM2 key spec is only available in China Regions.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type Recipient

dict

param Recipient

A signed attestation document from an Amazon Web Services Nitro enclave and the encryption algorithm to use with the enclave's public key. The only valid encryption algorithm is RSAES_OAEP_SHA_256 .

This parameter only supports attestation documents for Amazon Web Services Nitro Enclaves. To include this parameter, use the Amazon Web Services Nitro Enclaves SDK or any Amazon Web Services SDK.

When you use this parameter, instead of returning a plaintext copy of the private data key, KMS encrypts the plaintext private data key under the public key in the attestation document, and returns the resulting ciphertext in the CiphertextForRecipient field in the response. This ciphertext can be decrypted only with the private key in the enclave. The CiphertextBlob field in the response contains a copy of the private data key encrypted under the KMS key specified by the KeyId parameter. The PrivateKeyPlaintext field in the response is null or empty.

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 .

KeyEncryptionAlgorithm (string) --

The encryption algorithm that KMS should use with the public key for an Amazon Web Services Nitro Enclave to encrypt plaintext values for the response. The only valid value is RSAES_OAEP_SHA_256 .
AttestationDocument (bytes) --

The attestation document for an Amazon Web Services Nitro Enclave. This document includes the enclave's public key.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'PrivateKeyCiphertextBlob': b'bytes',
    'PrivateKeyPlaintext': b'bytes',
    'PublicKey': b'bytes',
    'KeyId': 'string',
    'KeyPairSpec': 'RSA_2048'|'RSA_3072'|'RSA_4096'|'ECC_NIST_P256'|'ECC_NIST_P384'|'ECC_NIST_P521'|'ECC_SECG_P256K1'|'SM2',
    'CiphertextForRecipient': b'bytes'
}

Response Structure

(dict) --
- PrivateKeyCiphertextBlob (bytes) --
  
  The encrypted copy of the private key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- PrivateKeyPlaintext (bytes) --
  
  The plaintext copy of the private key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
  
  If the response includes the CiphertextForRecipient field, the PrivateKeyPlaintext field is null or empty.
- PublicKey (bytes) --
  
  The public key (in plaintext). When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that encrypted the private key.
- KeyPairSpec (string) --
  
  The type of data key pair that was generated.
- CiphertextForRecipient (bytes) --
  
  The plaintext private data key encrypted with the public key from the Nitro enclave. This ciphertext can be decrypted only by using a private key in the Nitro enclave.
  
  This field is included in the response only when the Recipient parameter in the request includes a valid attestation document from an Amazon Web Services Nitro enclave. 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 .

GenerateDataKeyPairWithoutPlaintext (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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.

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 .

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

See also: AWS API Documentation

Request Syntax

client.generate_data_key_pair_without_plaintext(
    EncryptionContext={
        'string': 'string'
    },
    KeyId='string',
    KeyPairSpec='RSA_2048'|'RSA_3072'|'RSA_4096'|'ECC_NIST_P256'|'ECC_NIST_P384'|'ECC_NIST_P521'|'ECC_SECG_P256K1'|'SM2',
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context that will be used when encrypting the private key in the data key pair.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type KeyId

string

param KeyId

[REQUIRED]

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type KeyPairSpec

string

param KeyPairSpec

[REQUIRED]

Determines the type of data key pair that is generated.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'PrivateKeyCiphertextBlob': b'bytes',
    'PublicKey': b'bytes',
    'KeyId': 'string',
    'KeyPairSpec': 'RSA_2048'|'RSA_3072'|'RSA_4096'|'ECC_NIST_P256'|'ECC_NIST_P384'|'ECC_NIST_P521'|'ECC_SECG_P256K1'|'SM2'
}

Response Structure

(dict) --
- PrivateKeyCiphertextBlob (bytes) --
  
  The encrypted copy of the private key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- PublicKey (bytes) --
  
  The public key (in plaintext). When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that encrypted the private key.
- KeyPairSpec (string) --
  
  The type of data key pair that was generated.

GenerateDataKeyWithoutPlaintext (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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.

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

See also: AWS API Documentation

Request Syntax

client.generate_data_key_without_plaintext(
    KeyId='string',
    EncryptionContext={
        'string': 'string'
    },
    KeySpec='AES_256'|'AES_128',
    NumberOfBytes=123,
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type EncryptionContext

dict

param EncryptionContext

Specifies the encryption context that will be used when encrypting the data key.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type KeySpec

string

param KeySpec

The length of the data key. Use AES_128 to generate a 128-bit symmetric key, or AES_256 to generate a 256-bit symmetric key.

type NumberOfBytes

integer

param NumberOfBytes

The length of the data key in bytes. For example, use the value 64 to generate a 512-bit data key (64 bytes is 512 bits). For common key lengths (128-bit and 256-bit symmetric keys), we recommend that you use the KeySpec field instead of this one.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'CiphertextBlob': b'bytes',
    'KeyId': 'string'
}

Response Structure

(dict) --
- CiphertextBlob (bytes) --
  
  The encrypted data key. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that encrypted the data key.

GenerateMac (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 * .

Note

Best practices recommend that you limit the time during which any signing mechanism, including an HMAC, is effective. This deters an attack where the actor uses a signed message to establish validity repeatedly or long after the message is superseded. HMAC tags do not include a timestamp, but you can include a timestamp in the token or message to help you detect when its time to refresh the HMAC.

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

See also: AWS API Documentation

Request Syntax

client.generate_mac(
    Message=b'bytes',
    KeyId='string',
    MacAlgorithm='HMAC_SHA_224'|'HMAC_SHA_256'|'HMAC_SHA_384'|'HMAC_SHA_512',
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type Message

bytes

param Message

[REQUIRED]

The message to be hashed. Specify a message of up to 4,096 bytes.

GenerateMac and VerifyMac do not provide special handling for message digests. If you generate an HMAC for a hash digest of a message, you must verify the HMAC of the same hash digest.

type KeyId

string

param KeyId

[REQUIRED]

The HMAC KMS key to use in the operation. The MAC algorithm computes the HMAC for the message and the key as described in RFC 2104 .

To identify an HMAC KMS key, use the DescribeKey operation and see the KeySpec field in the response.

type MacAlgorithm

string

param MacAlgorithm

[REQUIRED]

The MAC algorithm used in the operation.

The algorithm must be compatible with the HMAC KMS key that you specify. To find the MAC algorithms that your HMAC KMS key supports, use the DescribeKey operation and see the MacAlgorithms field in the DescribeKey response.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'Mac': b'bytes',
    'MacAlgorithm': 'HMAC_SHA_224'|'HMAC_SHA_256'|'HMAC_SHA_384'|'HMAC_SHA_512',
    'KeyId': 'string'
}

Response Structure

(dict) --
- Mac (bytes) --
  
  The hash-based message authentication code (HMAC) that was generated for the specified message, HMAC KMS key, and MAC algorithm.
  
  This is the standard, raw HMAC defined in RFC 2104 .
- MacAlgorithm (string) --
  
  The MAC algorithm that was used to generate the HMAC.
- KeyId (string) --
  
  The HMAC KMS key used in the operation.

ReEncrypt (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 the KMS key that protects a ciphertext. You can also use it to reencrypt ciphertext under the same KMS key, such as to change the encryption context of a ciphertext.

The ReEncrypt operation can decrypt ciphertext that was encrypted by using a KMS key in an KMS operation, such as Encrypt or GenerateDataKey . It can also decrypt ciphertext that was encrypted by using the public key of an asymmetric KMS key outside of KMS. However, it cannot decrypt 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.

When you use the ReEncrypt operation, you need to provide information for the decrypt operation and the subsequent encrypt operation.

If your ciphertext was encrypted under an asymmetric KMS key, you must use the SourceKeyId parameter to identify the KMS key that encrypted the ciphertext. You must also supply the encryption algorithm that was used. This information is required to decrypt the data.
If your ciphertext was encrypted under a symmetric encryption KMS key, the SourceKeyId 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 source KMS key is always recommended as a best practice. When you use the SourceKeyId parameter to specify a KMS key, KMS uses only the KMS key you specify. If the ciphertext was encrypted under a different KMS key, the ReEncrypt operation fails. This practice ensures that you use the KMS key that you intend.
To reencrypt the data, you must use the DestinationKeyId parameter to specify the KMS key that re-encrypts the data after it is decrypted. If the destination KMS key is an asymmetric KMS key, you must also provide the encryption algorithm. The algorithm that you choose must be compatible with the KMS key.

Warning

When you use an asymmetric KMS key to encrypt or reencrypt data, be sure to record the KMS key and encryption algorithm that you choose. You will be required to provide the same KMS key and encryption algorithm when you decrypt the data. If the KMS key and algorithm do not match the values used to encrypt the data, the decrypt operation fails. You are not required to supply the key ID and encryption algorithm when you decrypt with symmetric encryption KMS keys because KMS stores this information in the ciphertext blob. KMS cannot store metadata in ciphertext generated with asymmetric keys. The standard format for asymmetric key ciphertext does not include configurable fields.

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. The source KMS key and destination KMS key can be in different Amazon Web Services accounts. Either or both KMS keys can be in a different account than the caller. To specify a KMS key in a different account, you must use its key ARN or alias ARN.

Required permissions :

kms:ReEncryptFrom permission on the source KMS key (key policy)
kms:ReEncryptTo permission on the destination KMS key (key policy)

To permit reencryption from or to a KMS key, include the "kms:ReEncrypt*" permission in your key policy . This permission is automatically included in the key policy when you use the console to create a KMS key. But you must include it manually when you create a KMS key programmatically or when you use the PutKeyPolicy operation to set a key policy.

Related operations:

Decrypt
Encrypt
GenerateDataKey
GenerateDataKeyPair

See also: AWS API Documentation

Request Syntax

client.re_encrypt(
    CiphertextBlob=b'bytes',
    SourceEncryptionContext={
        'string': 'string'
    },
    SourceKeyId='string',
    DestinationKeyId='string',
    DestinationEncryptionContext={
        'string': 'string'
    },
    SourceEncryptionAlgorithm='SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    DestinationEncryptionAlgorithm='SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type CiphertextBlob

bytes

param CiphertextBlob

[REQUIRED]

Ciphertext of the data to reencrypt.

type SourceEncryptionContext

dict

param SourceEncryptionContext

Specifies the encryption context to use to decrypt the ciphertext. Enter the same encryption context that was used to encrypt the ciphertext.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type SourceKeyId

string

param SourceKeyId

Specifies the KMS key that KMS will use to decrypt the ciphertext before it is re-encrypted.

Enter a key ID of the KMS key that was used to encrypt the ciphertext. If you identify a different KMS key, the ReEncrypt operation throws an IncorrectKeyException .

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type DestinationKeyId

string

param DestinationKeyId

[REQUIRED]

A unique identifier for the KMS key that is used to reencrypt the data. Specify a symmetric encryption KMS key or an asymmetric KMS key with a KeyUsage value of ENCRYPT_DECRYPT . To find the KeyUsage value of a KMS key, use the DescribeKey operation.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type DestinationEncryptionContext

dict

param DestinationEncryptionContext

Specifies that encryption context to use when the reencrypting the data.

Warning

Do not include confidential or sensitive information in this field. This field may be displayed in plaintext in CloudTrail logs and other output.

A destination encryption context is valid only when the destination KMS key is a symmetric encryption KMS key. The standard ciphertext format for asymmetric KMS keys does not include fields for metadata.

For more information, see Encryption context in the Key Management Service Developer Guide .

(string) --
- (string) --

type SourceEncryptionAlgorithm

string

param SourceEncryptionAlgorithm

Specifies the encryption algorithm that KMS will use to decrypt the ciphertext before it is reencrypted. The default value, SYMMETRIC_DEFAULT , represents the algorithm used for symmetric encryption KMS keys.

Specify the same algorithm that was used to encrypt the ciphertext. If you specify a different algorithm, the decrypt attempt fails.

This parameter is required only when the ciphertext was encrypted under an asymmetric KMS key.

type DestinationEncryptionAlgorithm

string

param DestinationEncryptionAlgorithm

Specifies the encryption algorithm that KMS will use to reecrypt the data after it has decrypted it. The default value, SYMMETRIC_DEFAULT , represents the encryption algorithm used for symmetric encryption KMS keys.

This parameter is required only when the destination KMS key is an asymmetric KMS key.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'CiphertextBlob': b'bytes',
    'SourceKeyId': 'string',
    'KeyId': 'string',
    'SourceEncryptionAlgorithm': 'SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE',
    'DestinationEncryptionAlgorithm': 'SYMMETRIC_DEFAULT'|'RSAES_OAEP_SHA_1'|'RSAES_OAEP_SHA_256'|'SM2PKE'
}

Response Structure

(dict) --
- CiphertextBlob (bytes) --
  
  The reencrypted data. When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- SourceKeyId (string) --
  
  Unique identifier of the KMS key used to originally encrypt the data.
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the KMS key that was used to reencrypt the data.
- SourceEncryptionAlgorithm (string) --
  
  The encryption algorithm that was used to decrypt the ciphertext before it was reencrypted.
- DestinationEncryptionAlgorithm (string) --
  
  The encryption algorithm that was used to reencrypt the data.

RetireGrant (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 ARN) of the KMS key. The CreateGrant operation returns both values.

This operation can be called by the retiring principal for a grant, by the grantee principal if the grant allows the RetireGrant operation, and by the Amazon Web Services account in which the grant is created. It can also be called by principals to whom permission for retiring a grant is delegated. For details, see Retiring and revoking grants in the Key Management Service Developer Guide .

Cross-account use : Yes. You can retire a grant on a KMS key in a different Amazon Web Services account.

Required permissions: :Permission to retire a grant is determined primarily by the grant. For details, see Retiring and revoking grants in the Key Management Service Developer Guide .

Related operations:

CreateGrant
ListGrants
ListRetirableGrants
RevokeGrant

See also: AWS API Documentation

Request Syntax

client.retire_grant(
    GrantToken='string',
    KeyId='string',
    GrantId='string',
    DryRun=True|False
)

type GrantToken

string

param GrantToken

Identifies the grant to be retired. You can use a grant token to identify a new grant even before it has achieved eventual consistency.

Only the CreateGrant operation returns a grant token. For details, see Grant token and Eventual consistency in the Key Management Service Developer Guide .

type KeyId

string

param KeyId

The key ARN KMS key associated with the grant. To find the key ARN, use the ListKeys operation.

For example: arn:aws:kms:us-east-2:444455556666:key/1234abcd-12ab-34cd-56ef-1234567890ab

type GrantId

string

param GrantId

Identifies the grant to retire. To get the grant ID, use CreateGrant , ListGrants , or ListRetirableGrants .

Grant ID Example - 0123456789012345678901234567890123456789012345678901234567890123

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

returns

None

RevokeGrant (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 Guide * .

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 . For details, see Eventual consistency 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:RevokeGrant (key policy).

Related operations:

CreateGrant
ListGrants
ListRetirableGrants
RetireGrant

See also: AWS API Documentation

Request Syntax

client.revoke_grant(
    KeyId='string',
    GrantId='string',
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

A unique identifier for the KMS key associated with the grant. To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey .

Specify the key ID or key ARN of the KMS key. To specify a KMS key in a different Amazon Web Services account, you must use the key ARN.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey .

type GrantId

string

param GrantId

[REQUIRED]

Identifies the grant to revoke. To get the grant ID, use CreateGrant , ListGrants , or ListRetirableGrants .

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

returns

None

Sign (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 the same asymmetric KMS key outside of KMS. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide .

Digital signatures are generated and verified by using asymmetric key pair, such as an RSA or ECC pair that is represented by an asymmetric KMS key. The key owner (or an authorized user) uses their private key to sign a message. Anyone with the public key can verify that the message was signed with that particular private key and that the message hasn't changed since it was signed.

To use the Sign operation, provide the following information:

Use the KeyId parameter to identify an asymmetric KMS key with a KeyUsage value of SIGN_VERIFY . To get the KeyUsage value of a KMS key, use the DescribeKey operation. The caller must have kms:Sign permission on the KMS key.
Use the Message parameter to specify the message or message digest to sign. You can submit messages of up to 4096 bytes. To sign a larger message, generate a hash digest of the message, and then provide the hash digest in the Message parameter. To indicate whether the message is a full message or a digest, use the MessageType parameter.
Choose a signing algorithm that is compatible with the KMS key.

Warning

When signing a message, be sure to record the KMS key and the signing algorithm. This information is required to verify the signature.

Note

Best practices recommend that you limit the time during which any signature is effective. This deters an attack where the actor uses a signed message to establish validity repeatedly or long after the message is superseded. Signatures do not include a timestamp, but you can include a timestamp in the signed message to help you detect when its time to refresh the signature.

To verify the signature that this operation generates, use the Verify operation. Or use the GetPublicKey operation to download the public key and then use the public key to verify the signature outside of KMS.

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:Sign (key policy)

Related operations : Verify

See also: AWS API Documentation

Request Syntax

client.sign(
    KeyId='string',
    Message=b'bytes',
    MessageType='RAW'|'DIGEST',
    GrantTokens=[
        'string',
    ],
    SigningAlgorithm='RSASSA_PSS_SHA_256'|'RSASSA_PSS_SHA_384'|'RSASSA_PSS_SHA_512'|'RSASSA_PKCS1_V1_5_SHA_256'|'RSASSA_PKCS1_V1_5_SHA_384'|'RSASSA_PKCS1_V1_5_SHA_512'|'ECDSA_SHA_256'|'ECDSA_SHA_384'|'ECDSA_SHA_512'|'SM2DSA',
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

Identifies an asymmetric KMS key. KMS uses the private key in the asymmetric KMS key to sign the message. The KeyUsage type of the KMS key must be SIGN_VERIFY . To find the KeyUsage of a KMS key, use the DescribeKey operation.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type Message

bytes

param Message

[REQUIRED]

Specifies the message or message digest to sign. Messages can be 0-4096 bytes. To sign a larger message, provide a message digest.

If you provide a message digest, use the DIGEST value of MessageType to prevent the digest from being hashed again while signing.

type MessageType

string

param MessageType

Tells KMS whether the value of the Message parameter should be hashed as part of the signing algorithm. Use RAW for unhashed messages; use DIGEST for message digests, which are already hashed.

When the value of MessageType is RAW , KMS uses the standard signing algorithm, which begins with a hash function. When the value is DIGEST , KMS skips the hashing step in the signing algorithm.

Warning

Use the DIGEST value only when the value of the Message parameter is a message digest. If you use the DIGEST value with an unhashed message, the security of the signing operation can be compromised.

When the value of MessageType is DIGEST , the length of the Message value must match the length of hashed messages for the specified signing algorithm.

You can submit a message digest and omit the MessageType or specify RAW so the digest is hashed again while signing. However, this can cause verification failures when verifying with a system that assumes a single hash.

The hashing algorithm in that Sign uses is based on the SigningAlgorithm value.

Signing algorithms that end in SHA_256 use the SHA_256 hashing algorithm.
Signing algorithms that end in SHA_384 use the SHA_384 hashing algorithm.
Signing algorithms that end in SHA_512 use the SHA_512 hashing algorithm.
SM2DSA uses the SM3 hashing algorithm. For details, see Offline verification with SM2 key pairs .

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type SigningAlgorithm

string

param SigningAlgorithm

[REQUIRED]

Specifies the signing algorithm to use when signing the message.

Choose an algorithm that is compatible with the type and size of the specified asymmetric KMS key. When signing with RSA key pairs, RSASSA-PSS algorithms are preferred. We include RSASSA-PKCS1-v1_5 algorithms for compatibility with existing applications.

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'KeyId': 'string',
    'Signature': b'bytes',
    'SigningAlgorithm': 'RSASSA_PSS_SHA_256'|'RSASSA_PSS_SHA_384'|'RSASSA_PSS_SHA_512'|'RSASSA_PKCS1_V1_5_SHA_256'|'RSASSA_PKCS1_V1_5_SHA_384'|'RSASSA_PKCS1_V1_5_SHA_512'|'ECDSA_SHA_256'|'ECDSA_SHA_384'|'ECDSA_SHA_512'|'SM2DSA'
}

Response Structure

(dict) --
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the asymmetric KMS key that was used to sign the message.
- Signature (bytes) --
  
  The cryptographic signature that was generated for the message.
  - When used with the supported RSA signing algorithms, the encoding of this value is defined by PKCS #1 in RFC 8017 .
  - When used with the ECDSA_SHA_256 , ECDSA_SHA_384 , or ECDSA_SHA_512 signing algorithms, this value is a DER-encoded object as defined by ANSI X9.62–2005 and RFC 3279 Section 2.2.3 . This is the most commonly used signature format and is appropriate for most uses.
  When you use the HTTP API or the Amazon Web Services CLI, the value is Base64-encoded. Otherwise, it is not Base64-encoded.
- SigningAlgorithm (string) --
  
  The signing algorithm that was used to sign the message.

Verify (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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 message hasn't changed since it was signed. If the signature is verified, the value of the SignatureValid field in the response is True . If the signature verification fails, the Verify operation fails with an KMSInvalidSignatureException exception.

A digital signature is generated by using the private key in an asymmetric KMS key. The signature is verified by using the public key in the same asymmetric KMS key. For information about asymmetric KMS keys, see Asymmetric KMS keys in the Key Management Service Developer Guide .

To use the Verify operation, specify the same asymmetric KMS key, message, and signing algorithm that were used to produce the signature. The message type does not need to be the same as the one used for signing, but it must indicate whether the value of the Message parameter should be hashed as part of the verification process.

You can also verify the digital signature by using the public key of the KMS key outside of KMS. Use the GetPublicKey operation to download the public key in the asymmetric KMS key and then use the public key to verify the signature outside of KMS. The advantage of using the Verify operation is that it is performed within KMS. As a result, it's easy to call, the operation is performed within the FIPS boundary, it is logged in CloudTrail, and you can use key policy and IAM policy to determine who is authorized to use the KMS key to verify signatures.

To verify a signature outside of KMS with an SM2 public key (China Regions only), you must specify the distinguishing ID. By default, KMS uses 1234567812345678 as the distinguishing ID. For more information, see Offline verification with SM2 key pairs .

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:Verify (key policy)

Related operations : Sign

See also: AWS API Documentation

Request Syntax

client.verify(
    KeyId='string',
    Message=b'bytes',
    MessageType='RAW'|'DIGEST',
    Signature=b'bytes',
    SigningAlgorithm='RSASSA_PSS_SHA_256'|'RSASSA_PSS_SHA_384'|'RSASSA_PSS_SHA_512'|'RSASSA_PKCS1_V1_5_SHA_256'|'RSASSA_PKCS1_V1_5_SHA_384'|'RSASSA_PKCS1_V1_5_SHA_512'|'ECDSA_SHA_256'|'ECDSA_SHA_384'|'ECDSA_SHA_512'|'SM2DSA',
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type KeyId

string

param KeyId

[REQUIRED]

Identifies the asymmetric KMS key that will be used to verify the signature. This must be the same KMS key that was used to generate the signature. If you specify a different KMS key, the signature verification fails.

For example:

Key ID: 1234abcd-12ab-34cd-56ef-1234567890ab
Key ARN: arn:aws:kms:us-east-2:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab
Alias name: alias/ExampleAlias
Alias ARN: arn:aws:kms:us-east-2:111122223333:alias/ExampleAlias

To get the key ID and key ARN for a KMS key, use ListKeys or DescribeKey . To get the alias name and alias ARN, use ListAliases .

type Message

bytes

param Message

[REQUIRED]

Specifies the message that was signed. You can submit a raw message of up to 4096 bytes, or a hash digest of the message. If you submit a digest, use the MessageType parameter with a value of DIGEST .

If the message specified here is different from the message that was signed, the signature verification fails. A message and its hash digest are considered to be the same message.

type MessageType

string

param MessageType

Tells KMS whether the value of the Message parameter should be hashed as part of the signing algorithm. Use RAW for unhashed messages; use DIGEST for message digests, which are already hashed.

When the value of MessageType is RAW , KMS uses the standard signing algorithm, which begins with a hash function. When the value is DIGEST , KMS skips the hashing step in the signing algorithm.

Warning

Use the DIGEST value only when the value of the Message parameter is a message digest. If you use the DIGEST value with an unhashed message, the security of the verification operation can be compromised.

When the value of MessageType is DIGEST , the length of the Message value must match the length of hashed messages for the specified signing algorithm.

You can submit a message digest and omit the MessageType or specify RAW so the digest is hashed again while signing. However, if the signed message is hashed once while signing, but twice while verifying, verification fails, even when the message hasn't changed.

The hashing algorithm in that Verify uses is based on the SigningAlgorithm value.

Signing algorithms that end in SHA_256 use the SHA_256 hashing algorithm.
Signing algorithms that end in SHA_384 use the SHA_384 hashing algorithm.
Signing algorithms that end in SHA_512 use the SHA_512 hashing algorithm.
SM2DSA uses the SM3 hashing algorithm. For details, see Offline verification with SM2 key pairs .

type Signature

bytes

param Signature

[REQUIRED]

The signature that the Sign operation generated.

type SigningAlgorithm

string

param SigningAlgorithm

[REQUIRED]

The signing algorithm that was used to sign the message. If you submit a different algorithm, the signature verification fails.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'KeyId': 'string',
    'SignatureValid': True|False,
    'SigningAlgorithm': 'RSASSA_PSS_SHA_256'|'RSASSA_PSS_SHA_384'|'RSASSA_PSS_SHA_512'|'RSASSA_PKCS1_V1_5_SHA_256'|'RSASSA_PKCS1_V1_5_SHA_384'|'RSASSA_PKCS1_V1_5_SHA_512'|'ECDSA_SHA_256'|'ECDSA_SHA_384'|'ECDSA_SHA_512'|'SM2DSA'
}

Response Structure

(dict) --
- KeyId (string) --
  
  The Amazon Resource Name (key ARN ) of the asymmetric KMS key that was used to verify the signature.
- SignatureValid (boolean) --
  
  A Boolean value that indicates whether the signature was verified. A value of True indicates that the Signature was produced by signing the Message with the specified KeyID and SigningAlgorithm. If the signature is not verified, the Verify operation fails with a KMSInvalidSignatureException exception.
- SigningAlgorithm (string) --
  
  The signing algorithm that was used to verify the signature.

VerifyMac (updated)

Link ¶
Changes (request)

{'DryRun': 'boolean'}

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, and MAC algorithm that you specify, and compares the computed HMAC to the HMAC that you specify. If the HMACs are identical, the verification succeeds; otherwise, it fails. Verification indicates that the message hasn't changed since the HMAC was calculated, and the specified key was used to generate and verify the HMAC.

HMAC KMS keys and the HMAC algorithms that KMS uses conform to industry standards defined in RFC 2104 .

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:VerifyMac (key policy)

Related operations : GenerateMac

See also: AWS API Documentation

Request Syntax

client.verify_mac(
    Message=b'bytes',
    KeyId='string',
    MacAlgorithm='HMAC_SHA_224'|'HMAC_SHA_256'|'HMAC_SHA_384'|'HMAC_SHA_512',
    Mac=b'bytes',
    GrantTokens=[
        'string',
    ],
    DryRun=True|False
)

type Message

bytes

param Message

[REQUIRED]

The message that will be used in the verification. Enter the same message that was used to generate the HMAC.

GenerateMac and VerifyMac do not provide special handling for message digests. If you generated an HMAC for a hash digest of a message, you must verify the HMAC for the same hash digest.

type KeyId

string

param KeyId

[REQUIRED]

The KMS key that will be used in the verification.

Enter a key ID of the KMS key that was used to generate the HMAC. If you identify a different KMS key, the VerifyMac operation fails.

type MacAlgorithm

string

param MacAlgorithm

[REQUIRED]

The MAC algorithm that will be used in the verification. Enter the same MAC algorithm that was used to compute the HMAC. This algorithm must be supported by the HMAC KMS key identified by the KeyId parameter.

type Mac

bytes

param Mac

[REQUIRED]

The HMAC to verify. Enter the HMAC that was generated by the GenerateMac operation when you specified the same message, HMAC KMS key, and MAC algorithm as the values specified in this request.

type GrantTokens

list

param GrantTokens

A list of grant tokens.

(string) --

type DryRun

boolean

param DryRun

Checks if your request will succeed. DryRun is an optional parameter.

To learn more about how to use this parameter, see Testing your KMS API calls in the Key Management Service Developer Guide .

rtype

dict

returns

Response Syntax

{
    'KeyId': 'string',
    'MacValid': True|False,
    'MacAlgorithm': 'HMAC_SHA_224'|'HMAC_SHA_256'|'HMAC_SHA_384'|'HMAC_SHA_512'
}

Response Structure

(dict) --
- KeyId (string) --
  
  The HMAC KMS key used in the verification.
- MacValid (boolean) --
  
  A Boolean value that indicates whether the HMAC was verified. A value of True indicates that the HMAC (Mac ) was generated with the specified Message , HMAC KMS key (KeyID ) and MacAlgorithm. .
  
  If the HMAC is not verified, the VerifyMac operation fails with a KMSInvalidMacException exception. This exception indicates that one or more of the inputs changed since the HMAC was computed.
- MacAlgorithm (string) --
  
  The MAC algorithm used in the verification.