Signs a blob using a service account's system-managed private key.
HTTP request
 POST https://iamcredentials.googleapis.com/v1/{name=projects/*/serviceAccounts/*}:signBlob 
The URL uses gRPC Transcoding syntax.
Path parameters
name 
 string 
Required. The resource name of the service account for which the credentials are requested, in the following format: projects/-/serviceAccounts/{ACCOUNT_EMAIL_OR_UNIQUEID} 
. The - 
wildcard character is required; replacing it with a project ID is invalid.
Authorization requires the following IAM 
permission on the specified resource name 
:
-  iam.serviceAccounts.signBlob
Request body
The request body contains data with the following structure:
| JSON representation | 
|---|
| { "delegates" : [ string ] , "payload" : string } | 
| Fields | |
|---|---|
| delegates[] |   The sequence of service accounts in a delegation chain. Each service account must be granted the  The delegates must have the following format:  | 
| payload |   Required. The bytes to sign. A base64-encoded string. | 
Response body
If successful, the response body contains data with the following structure:
| JSON representation | 
|---|
| { "keyId" : string , "signedBlob" : string } | 
keyId 
 string 
The ID of the key used to sign the blob. The key used for signing will remain valid for at least 12 hours after the blob is signed. To verify the signature, you can retrieve the public key in several formats from the following endpoints:
- RSA public key wrapped in an X.509 v3 certificate: https://www.googleapis.com/service_accounts/v1/metadata/x509/{ACCOUNT_EMAIL}
- Raw key in JSON format: https://www.googleapis.com/service_accounts/v1/metadata/raw/{ACCOUNT_EMAIL}
- JSON Web Key (JWK): https://www.googleapis.com/service_accounts/v1/metadata/jwk/{ACCOUNT_EMAIL}
signedBlob 
 string ( bytes 
format) 
The signature for the blob. Does not include the original blob.
After the key pair referenced by the keyId 
response field expires, Google no longer exposes the public key that can be used to verify the blob. As a result, the receiver can no longer verify the signature.
A base64-encoded string.
Authorization scopes
Requires one of the following OAuth scopes:
-  https://www.googleapis.com/auth/iam
-  https://www.googleapis.com/auth/cloud-platform
For more information, see the Authentication Overview .

