---
title: "Content Credential Signature Verifier"
method: POST
path: "/v1/tools/verify_content_credential_signature"
tags: ["c2pa", "signature", "cose", "ed25519", "content-credentials", "eu-ai-act", "wave23"]
---

# Content Credential Signature Verifier

`POST /v1/tools/verify_content_credential_signature`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/verify_content_credential_signature`
- Auth: none declared

Assess a C2PA COSE_Sign1 content-credential signature policy. The caller performs the signature check over the manifest bytes with the declared alg (Ed25519/ES256/ES384/PS256) and attests the outcome via the required signature_verified input; the kernel does not re-verify. Trust posture is caller-supplied: zero network, no OCSP. Emits ACCEPT or REFUSE.

**Tool URL:** https://ainumbers.co/chaingraph/art-124-content-credential-signature-verifier.html
**AP2/Policy Mandate export:** yes

## Request body

- object
  - `alg` 'Ed25519' | 'ES256' | 'ES384' | 'PS256', required
  - `signature_verified` boolean, required: result of the caller's signature check over the manifest bytes with the declared alg; the kernel does not re-verify
  - `trust_anchor_match` boolean, required
  - `cert_not_expired` boolean
  - `revocation_status` string, required

## Response `200`

Successful tool execution result

- object
  - `signature_verified` boolean
  - `signature_verification` 'caller_attested'
  - `caveats` string[]
  - `chain_trusted` boolean
  - `alg` string
  - `alg_allowed` boolean
  - `verdict` 'ACCEPT' | 'REFUSE'

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)