This repository contains two things:
- A client implementation of the roughtime protocol, in the roughtime package.
- A small tool called notary, which uses the roughtime protocol to obtain a cryptographic proof that a given file exists at the current time.
The notary tool achieves this by calculating a cryptographic hash of the given file and using it as the initial nonce in a roughtime request chain. The servers in the chain then sign this nonce, together with their view of what the current time is. The resulting chain can then be stored and used as proof that the file existed previously (as long as at least one server in the chain is trusted).