Browser Extension

Automatically timestamps every AI conversation turn on Claude, ChatGPT, and Gemini using RFC 3161

sigill-browser-extension
v0.5.0 · Chrome · Manifest V3 · Apache 2.0

Captures each AI conversation turn from the platform's own API stream — real message IDs, model identifiers, and completion events, not screen scraping. Every turn becomes a signed evidence envelope: canonicalized with RFC 8785, hashed with SHA-256, and timestamped via RFC 3161. Only the hash leaves your browser. Turns are chained into a tamper-evident local ledger with hourly anchor stamps, attached and generated files are recorded by hash, and the exported evidence bundle verifies offline — no Sigill required.

When the log matters, seal it: one click signs the evidence bundle with a CAdES detached signature under your Sigill certificate, with an embedded trusted timestamp — qualified timestamps supported. The bundle is hashed locally and only the hash is signed, so even sealing never uploads your conversations. The result is a portable pair — bundle plus .p7s — that stands on its own in any signature validation tool.

ClaudeChatGPTGemini
Add to Chrome — Chrome Web Store Source on GitHub

Installation

  1. Add the extension from the Chrome Web Store.
  2. Visit sigill.ai while signed in — the extension picks up your identity automatically.
  3. Open Claude, ChatGPT, or Gemini and work as usual — captured turns appear under Evidence.
The Chrome Web Store is the only official distribution channel — updates arrive automatically through the store. The source is public on GitHub. Your conversations stay on your device — see the extension privacy policy for exactly what is collected and what leaves the browser.