Creates a digital signature for a
message or message digest by using the private key in an asymmetric CMK.
To verify the signature, use the verify operation, or
use the public key in the same asymmetric CMK outside of AWS KMS. For
information about symmetric and asymmetric CMKs, see Using Symmetric and Asymmetric CMKs
in the AWS 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 customer master key (CMK). 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 CMK with a
KeyUsage value of SIGN_VERIFY. To get the KeyUsage value of a
CMK, use the describe_key operation. The
caller must have kms:Sign permission on the CMK.
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 CMK.
When signing a message, be sure to record the CMK and the signing algorithm. This information is required to verify the signature.
To verify the signature that this operation generates, use the
verify operation. Or use the
get_public_key operation to download the public
key and then use the public key to verify the signature outside of AWS
KMS.
The CMK that you use for this operation must be in a compatible key state. For details, see How Key State Affects Use of a Customer Master Key in the AWS Key Management Service Developer Guide.
Cross-account use: Yes. To perform this operation with a CMK in a
different AWS account, specify the key ARN or alias ARN in the value of
the KeyId parameter.
Required permissions: kms:Sign (key policy)
Related operations: verify
kms_sign(KeyId, Message, MessageType, GrantTokens, SigningAlgorithm)[required] Identifies an asymmetric CMK. AWS KMS uses the private key in the
asymmetric CMK to sign the message. The KeyUsage type of the CMK must
be SIGN_VERIFY. To find the KeyUsage of a CMK, use the
describe_key operation.
To specify a CMK, use its key ID, Amazon Resource Name (ARN), alias
name, or alias ARN. When using an alias name, prefix it with "alias/".
To specify a CMK in a different AWS 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 CMK, use
list_keys or describe_key. To
get the alias name and alias ARN, use
list_aliases.
[required] Specifies the message or message digest to sign. Messages can be 0-4096 bytes. To sign a larger message, provide the message digest.
If you provide a message, AWS KMS generates a hash digest of the message and then signs it.
Tells AWS KMS whether the value of the Message parameter is a message
or message digest. The default value, RAW, indicates a message. To
indicate a message digest, enter DIGEST.
A list of grant tokens.
For more information, see Grant Tokens in the AWS Key Management Service Developer Guide.
[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 CMK.
A list with the following syntax:
list( KeyId = "string", Signature = raw, 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" )
svc$sign(
KeyId = "string",
Message = raw,
MessageType = "RAW"|"DIGEST",
GrantTokens = list(
"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"
)