For firms

A firm dates a draft, a contract version or a report by sending only its SHA-256 fingerprint; the file itself never leaves your systems. Each receipt records that those exact bytes existed by a specific Bitcoin block, and comes with an OpenTimestamps proof file that anyone can check later without an account and without relying on SoulInTime. Keep the original file and its proof together, and send the receipt link with the file when you share it. A receipt records bytes and timing only; it does not certify contents, authorship, or any legal conclusion.

See a real receipt: the Bitcoin whitepaper abstract · Pricing · Technical details · Questions: GitHub issues