Signal — ثقة القنوات

WhatsApp Cloud API: when a message is forwarded to a business number, the webhook only includes the phone of the person who forwarded it, context.forwarded and the content — never the original sender. Forwarded WhatsApp checks can only analyze content/links; channel attribution comes from sender-side claims.

Telegram Bot API: forward_origin includes the original sender (except privacy → MessageOriginHiddenUser). Third-party verification enables real receiver-side attribution plus a native badge.

Each brand declares and signs its official perimeter: the only domains, WhatsApp numbers, Telegram channels and short links it uses. The engine asks whether the artifact is inside or outside the perimeter against a signed allowlist. The perimeter is the published Official Channel Log entry.

SecureStamp never asserts intent. The verdict is a closed set of facts:

• PERTENECEThe channel is inside the brand’s declared and signed perimeter.
• NO_PERTENECEThe channel is outside the perimeter, optionally with observed signals.
• COUNTERSTAMPThe brand issued a confirmed counter-stamp against the channel.
• DISPUTEDThe case is under dispute and due process.
• UNKNOWNThe brand has not declared a perimeter in SecureStamp.

The 5 states map to L1–L5. The strong L1 state requires a brand-signed counter-stamp in state confirmed; the algorithmic case never imputes intent.

Official Channel Log — TLP:CLEAR: first-party assertions about a brand’s own channels. Public lookup, history and revocations.

Abuse Transparency Log — TLP:AMBER: third-party assertions. Only cryptographic commitments and aggregate counts are public; detail remains restricted. A concrete case is proven with a Merkle inclusion proof against the public tree head.

Not an arbitrary blacklist: it has states and due process.

Only confirmed enables L1; disputedis the dispute path for the channel owner.

Every verification produces a Trust Receipt: ES256-signed, timestamped, with idSSF-EV-… and re-verifiable by anyone. It reuses SecureStamp’s notarial key, so a third party verifies a receipt with the same/.well-known/jwks.json used for email stamps. Header typ: SSCT-receipt.