Proofsnap

ProofSnap is a browser extension for Chrome and Edge that turns any web page into a forensic evidence package intended to withstand authentication challenges in legal proceedings.

Key features and functions include:

Web Page Capture
The extension reloads the active tab to record the server response directly, then collects a full-page screenshot, the HTML source, extracted readable text, and technical metadata. Pages that load content on scroll, including chat and feed-based interfaces, are captured section by section.

Cryptographic Integrity
Every file in a capture is hashed with SHA-256, and the resulting manifest is signed with an RSA-4096 key. A separate chain-of-custody record and tamper-evident forensic log are included, intended to align with ISO/IEC 27037.

Time Anchoring
Capture time is recorded against NTP-verified time on every package. Depending on plan, this can be supplemented with a Bitcoin blockchain timestamp via OpenTimestamps or an EU qualified electronic timestamp under Regulation (EU) No 910/2014 (eIDAS), issued by Disig a.s., a qualified trust service provider on the EU Trusted List.

US Filing Support
Packages intended for use in United States court filings include a pre-filled declaration referencing Federal Rules of Evidence 902(13) and 902(14).

Multi-Tab and Video Capture
Beyond single-page capture, ProofSnap can record video of a capture session, document every tab visited during a multi-tab browsing session in a single package, and certify files that already exist on a user's device, transmitting only a hash rather than the file itself.

Forensic Mode
An opt-in capture depth available on higher-tier plans that additionally archives the page's network layer, including a WARC copy of the load, an HTTP Archive (HAR) log of requests and responses, individually hashed page resources, and TLS certificate chain details.

Provenance and Deepfake Detection
Captures include a Provenance Certificate performing integrity checks intended to indicate whether evidence is an unaltered original, along with a C2PA Content Credentials manifest interoperable with the Content Authenticity Initiative standard.

Independent Verification
Evidence packages can be checked without relying on the vendor, using a free web-based Trust Verifier, a command-line tool published under the MIT license, or bundled verification scripts for Windows, macOS, and Linux.