Signing Data

Function

This API is used to use the private key of an asymmetric key to digitally sign a message or digest.

Constraints

Only the asymmetric key whose key_usage is SIGN_VERIFY can be used for signature.

URI

POST /v1.0/{project_id}/kms/sign

**Table 1** URI parameter
Parameter	Mandatory	Type	Description
project_id	Yes	String	Project ID

Request Parameters

**Table 2** Request header parameters
Parameter	Mandatory	Type	Description
X-Auth-Token	Yes	String	User token. It can be obtained by calling the IAM API. (The token is the value of X-Subject-Token in the response header.)
Content-Type	Yes	String	application/json

**Table 3** Request body parameters
Parameter	Mandatory	Type	Description
key_id	Yes	String	The value can be a key ID, alias (key_alias), or URN. Key ID: A 36-byte string that matches the ^[0-9a-z]{8}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{4}-[0-9a-z]{12}$ regular expression, for example, 0d0466b0-e727-4d9c-b35d-f84bb474a37f Alias: An identifier of a key. The value starts with alias/, for example, alias/4555. URN: Each alias automatically matches a unique URN, for example, kms:eu-de-ring0:3ba44455500dd43127:alias:4555. NOTE: The alias_urn generated during key alias creation is the URN.
message	Yes	String	Message digest or message to be signed. The message must be encoded using Base64 and be less than 4096 bytes.
signing_algorithm	Yes	String	Signature algorithm. Possible values are as follows: 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
message_type	No	String	Message type. The default value is DIGEST. Possible values are as follows: DIGEST (message digest) RAW (original message)
sequence	No	String	A 36-byte serial number of a request message. Example: 919c82d4-8046-4722-9094-35c3c6524cff

Response Parameters

Status code: 200

**Table 4** Response body parameters
Parameter	Type	Description
key_id	String	CMK ID
signature	String	Signature value, which is encoded using Base64

Status code: 400

**Table 5** Response body parameter
Parameter	Type	Description
error	Object	Error message.

**Table 6** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 401

**Table 7** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 8** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 403

**Table 9** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 10** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 404

**Table 11** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 12** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 500

**Table 13** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 14** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 502

**Table 15** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 16** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Status code: 504

**Table 17** Response body parameter
Parameter	Type	Description
error	Object	Error message

**Table 18** ErrorDetail
Parameter	Type	Description
error_code	String	Error code
error_msg	String	Error information

Example Request

The following uses the RSASSA_PKCS1_V1_5_SHA_256 signature algorithm to sign the raw message.

{
 "key_id": "968d6cf0-feb6-42c6-bb30-d69f74f2d5f9",
 "message": "aGVsbG8g",
 "signing_algorithm": "RSASSA_PSS_SHA_256",
 "message_type": "RAW"
}

The following uses the RSASSA_PKCS1_V1_5_SHA_256 signature algorithm to sign the digest message.

{
 "key_id": "968d6cf0-feb6-42c6-bb30-d69f74f2d5f9",
 "message": "iNQmb9TmM40TuEX88olXnSCciXgjuSF9o+Fhk28DFYK=",
 "signing_algorithm": "RSASSA_PSS_SHA_256",
 "message_type": "DIGEST"
}

Example Response

Status code: 200

The following shows that the request for signing the raw message using the RSASSA_PKCS1_V1_5_SHA_256 signature algorithm is successful.

{
 "key_id": "968d6cf0-feb6-42c6-bb30-d69f74f2d5f9",
 "signature": "BqhL4PFPMNIXyEld3qviF7uqqnqlm9TcVCUN9FTRCr6KGreHIvwE4YuAc+eLWVSCGRd3bQHhDOQ9GlWjixGengwBix1RPP0qxtn2p7kQxkC2j76VjKCwqAsAy4MyxjN8RNOdnVCpOObDGoLxPHxUwNvSqZ6GxQKZ4cHPXVH0r/jH9csgk6IUr6ATyto+IcNWSvD03LfaNRQ+Rvc5tOzNFpFrMnVl319UG9ANscq1ne67VW2uQIf74Osg9DYzbJTf/xqW5GFi3ZoeQUu+gMxwgQp3pkuYhygjw6a8Qy9ZNMHmWnY199SzHrxgIq3ymQzUU5zrikKMColX2goPXf5fxQ=="
}

The following shows that the request for signing the digest message using the RSASSA_PKCS1_V1_5_SHA_256 signature algorithm is successful.

{
 "key_id": "968d6cf0-feb6-42c6-bb30-d69f74f2d5f9",
 "signature": "M8Gqrm7EyyCPckMs90D7IOlUPCMHhoBh+nz9ySvdbOi7JMrl0ei+2lb+CQ2ZJN+pu7mftotq7/sHt0wWsDl8IOywYSBtWEmLW6AHnEPMykG/A9/Dp3kRuuKFoouCzWXeZyhIrzRUunAK5j5njcY/yTf6T8M+zBy1nAApb8WcHUen9/j7+X348iOnsSuWNVfXxy3NX41v9kLn6x115UDA/798VLSoMbsjcXKgdf/3GoZRYjcHxiX6s71/RWsQYme68qQN2B0q8Y9lk6rQxrw/AXHFoeaphYb7PriURRx0GxhOEEHb/9Tcr39Zlh3bbl/2aF3ytJORWIqatLtqgJ4uEA=="
}

Status Codes

Status Code	Description
200	The request has succeeded.
400	Invalid request parameters.
401	Username and password are required to access the page requested.
403	Authentication failed.
404	The requested resource does not exist or is not found.
500	Internal service error.
502	Failed to complete the request. The server receives an invalid response from the upstream server.
504	Gateway timed out.