Signatures: receipts are signed with Ed25519 (WebCrypto). The public key is published at /.well-known/proofkit-pubkey; the private key never leaves the server environment.
Tamper evidence: each receipt digest is appended to a public hash chain; altering or removing an entry breaks the chain.
Transport: HTTPS only, served from Cloudflare’s edge.
Minimal data: pasted text is processed in memory and not stored (see Privacy).
Abuse protection: per-network rate limits and monthly free quota.
Report a vulnerability: info@sapir861.com — we respond within 72 hours.

Security