VerifyImageSignature - AI DeepSign - Alibaba Cloud Documentation Center

Verifies the C2PA signature in an image and returns the content integrity verification status and issuer certificate trust information.

Operation description

Signature types

Basic signature: Uses the platform's own certificate for signing. Supports content integrity verification.
Trusted signature: In addition to integrity verification, the signing certificate chain can be verified through the C2PA official trust list.

Verification result description

Content integrity verification checks whether the image and its signature-protected provenance information remain consistent with the state at the time of signing. It does not indicate that the visual content itself is authentic.
VerificationState=Valid indicates that the signature and data hash are valid and content integrity verification has passed. This alone cannot be used to determine that the signature is a trusted signature.
VerificationState=Trusted and IssuerTrusted present the certificate trust verification results. Whether a signature qualifies as a trusted signature as defined in this topic depends on whether the signing certificate chain can be verified through the C2PA official trust list, not solely on the certificate issuer name.

Request description

This operation verifies the C2PA (Coalition for Content Provenance and Authenticity) digital signature embedded in a specified image.
ImageUrl does not currently support images from external networks. Only image URLs accessible over the China public network are supported. Upload the image to an Alibaba Cloud OSS bucket in a China region first, and then use the presigned URL of the image as the input parameter for this operation. References: How do I obtain the URL of one or more objects?

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RAM authorization

The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.
API: The API that you can call to perform the action.
Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.
Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.
- For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.
- For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.
Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.
Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

Action

Access level

Resource type

Condition key

Dependent action

aideepsign:VerifyImageSignature

get

*All Resource

*

None

Request parameters

Parameter	Type	Required	Description	Example
ImageUrl	string	No	The URL of the image to verify. Specify either `ImageUrl` or `ObjectKey`. At least one of them is required.	https://example.com/signed-photo.jpg

Response elements

Element	Type	Description	Example
	object
Message	string	The additional information. The value `success` is returned if the request is successful.	success
RequestId	string	The request ID.	A1B2C3D4-E5F6-7890-ABCD-EF1234567890
Issuer	object	The issuer information.
CommonName	string	The common name (CN) of the issuer.	AIDeepSign User Certificate
Organization	string	The organization name (O) of the issuer.	Alibaba Cloud
HttpStatusCode	integer	The HTTP status code. The value `200` is returned if the request is successful.	200
VerificationState	string	The signature verification status. Valid values: Unsigned: The image does not contain C2PA data. Invalid: The signature, data hash, or C2PA structure is invalid. Valid: The signature and data hash are valid, but the issuer is not necessarily trusted. Trusted: The signature is valid and the issuer certificate is trusted. Valid values: Unsigned : Unsigned Valid : Valid Trusted : Trusted Invalid : Invalid	Valid
IssuerTrusted	boolean	Indicates whether the issuer is trusted. A value of true indicates that the issuer certificate is issued by a trusted certification authority (CA).
Manifest	object	The content credentials manifest information. This parameter is returned only when the image contains a C2PA signature.
Assertions	array<object>	The list of assertions, which contains metadata such as the provenance and editing history of the image.
	object
Data	string	The assertion data, which is detailed metadata in JSON format.	{"actions":[{"action":"c2pa.created"}]}
Label	string	The assertion label, such as c2pa.actions or stds.exif.	c2pa.actions
SignatureInfo	object	The signature details.
Alg	string	The signature algorithm, such as `ps256` or `es256`.	ps256
Issuer	string	The distinguished name (DN) of the signing certificate issuer.	CN=AIDeepSign CA,O=Alibaba Cloud
Time	string	The signing time in ISO 8601 format.	2026-06-18T10:30:00Z
Success	boolean	Indicates whether the request is successful.
Code	string	The business error code. The value "OK" is returned if the request is successful.	OK

Examples

Success response

JSON format

{
  "Message": "success",
  "RequestId": "A1B2C3D4-E5F6-7890-ABCD-EF1234567890",
  "Issuer": {
    "CommonName": "AIDeepSign User Certificate",
    "Organization": "Alibaba Cloud"
  },
  "HttpStatusCode": 200,
  "VerificationState": "Valid",
  "IssuerTrusted": false,
  "Manifest": {
    "Assertions": [
      {
        "Data": "{\"actions\":[{\"action\":\"c2pa.created\"}]}",
        "Label": "c2pa.actions"
      }
    ],
    "SignatureInfo": {
      "Alg": "ps256",
      "Issuer": "CN=AIDeepSign CA,O=Alibaba Cloud",
      "Time": "2026-06-18T10:30:00Z"
    }
  },
  "Success": false,
  "Code": "OK"
}

Error codes

HTTP status code	Error code	Error message	Description
400	IdempotentParameterMismatch	The request uses the same client token as a previous, but non-identical request. Do not reuse a client token with different requests, unless the requests are identical.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.