{"card_id":"ATC-2026-1509360","status":"active","spec_version":"ATC/1.0","payload":{"card_id":"ATC-2026-1509360","schema_version":"1.1.0","decision_authority":"consumer","agent_id":"skill.mn-sub-51326","agent_name":"awesome-mcp-servers","identity":{"public_key":"marketnow-skill:mn-sub-51326","key_algorithm":"Ed25519"},"trust":{"sentinel_review_score":0,"audit_layers_passed":{},"composite_trust":0,"risk_level":"not_audited","certificate_id":null},"capabilities":{"provides":["mcp-server"],"protocol_language":"mcp","translate":true},"payment":{"method":"x402 + USDC on Base L2","wallet_address":null},"metadata":{"issued_at":"2026-07-28T23:31:49.360Z","expires_at":"2026-10-26T23:31:49.360Z","issuer":"MarketNow Sentinel CA","revocation_url":"https://marketnow.site/api/atc?action=verify&card_id=ATC-2026-1509360"}},"attestation":{"signature":"83f0e57d2914292e4906f38269f3a5b44fb467e7130588874673b045864e6149c97b6c47eb3ae2e1ece2c8af7501f90089319c048de98e22e2485c9893765d06","signature_algorithm":"Ed25519 (RFC 8032)","signed_payload_hash":"d643921ff4ec4fbafa12f3d6283e0546bea58d686337e853eea5565b001957d9","canonicalization_method":"RFC 8785 JCS (JSON Canonicalization Scheme)","ca_key_id":"MCowBQYDK2VwAyEA","signed_at":"2026-07-28T23:31:49.360Z","signed_by":"MarketNow Sentinel CA","verify_with":"GET /api/atc?action=ca-key"},"verification_instructions":{"step_1":"Fetch the CA public key: GET /api/atc?action=ca-key","step_2":"Read attestation.canonicalization_method to determine which canonicalization to use","step_3":"If RFC_8785_JCS: canonicalize the payload using RFC 8785 JCS (blank out attestation.signature + signed_payload_hash first)","step_4":"If JSON.stringify_v8_sort: use JSON.stringify(payload, Object.keys(payload).sort()) (legacy cards issued before Aug 10, 2026)","step_5":"Verify the Ed25519 signature: crypto.verify(null, Buffer.from(canonical, \"utf8\"), publicKey, Buffer.from(signature, \"hex\"))"},"note":"This endpoint returns the exact bytes the issuer signed. The MarketNow /api/atc?action=verify endpoint uses the same bytes — closing the verification isolation gap reported by @anp2network."}