self-distributed verification

self-verifying case handoff

give someone a single file that holds both your .fc-case evidence record and the verifier needed to check it. everything needed to verify travels with the file — no fatcousin.com, no network, no install. drop a .fc-case below and fatcousin wraps it into one self-verifying .verify.html in your browser.

build the handoff file

drag a .fc-case here · or click to choose

your .fc-case is read and repackaged entirely in this browser. the only network request this page makes is loading the verifier template (a static fatcousin asset, no user data). the file you download contains no remote code and makes no network requests.

what the recipient gets

the downloaded .verify.html is a standalone page. opened on any device — even air-gapped, even from a usb stick — it immediately re-verifies the case it carries:

archive + hashes — unzips the embedded .fc-case and recomputes the sha-256 of manifest.json against the manifest.sha256 sidecar
ed25519 signatures — when present, validates the manifest and custody-log signatures against the public key embedded in the archive
chain-of-custody integrity — confirms the signed custody log is intact, bound to the manifest, and append-only ordered
rfc-3161 timestamp binding — checks any timestamp token is bound to this manifest hash (the issuer signature itself is not re-validated offline)

the verifier logic is the same audited code as the standalone offline verifier — inlined into the file, not fetched. the recipient can also drop other .fc-case files onto the same page to verify them too.

why this is safe to hand to opposing counsel

no remote code — the file contains no external script / style / img sources, no fetch, no XMLHttpRequest, no websockets, and no dynamic imports. this is enforced by a build-time guard and re-checked before every file you download
verifiable on its own terms — verification attests that the archive bytes match their embedded hashes and signatures and that the signing key did not change; it does not, by itself, bind that key to a named person
investigator-grade triage — a reproducibility and integrity check that supports examiner testimony and counsel review, not a substitute for upstream acquisition integrity or qualified legal advice

self-verifying case handoff

build the handoff file

drag a .fc-case here · or click to choose

what the recipient gets

the downloaded .verify.html is a standalone page. opened on any device — even air-gapped, even from a usb stick — it immediately re-verifies the case it carries:

archive + hashes — unzips the embedded .fc-case and recomputes the sha-256 of manifest.json against the manifest.sha256 sidecar

ed25519 signatures — when present, validates the manifest and custody-log signatures against the public key embedded in the archive

chain-of-custody integrity — confirms the signed custody log is intact, bound to the manifest, and append-only ordered

rfc-3161 timestamp binding — checks any timestamp token is bound to this manifest hash (the issuer signature itself is not re-validated offline)

why this is safe to hand to opposing counsel

no remote code — the file contains no external script / style / img sources, no fetch, no XMLHttpRequest, no websockets, and no dynamic imports. this is enforced by a build-time guard and re-checked before every file you download

verifiable on its own terms — verification attests that the archive bytes match their embedded hashes and signatures and that the signing key did not change; it does not, by itself, bind that key to a named person

investigator-grade triage — a reproducibility and integrity check that supports examiner testimony and counsel review, not a substitute for upstream acquisition integrity or qualified legal advice