The GNotary client is a multi-platform GUI client that allows you to select files via drag and drop from any file manager, create the secure hash sums for each file, and submit the hash list to a list of digital notary servers. Optionally, all selected files can be backed up into a zip archive. It is written in Python and requires the wxPython toolkit.
GNotary is a set of Python scripts that implement an asynchronous digital notary service. Anybody who needs certification of any digital document creates a message digest (like MD5 or RIPEMD160) of that document and submits it to the GNotary service by email. GNotary signs this email digitally (using GnuPG), retains a copy of the certified and time stamped message, and mails it back to the sender, optionally with the public key attached to allow the sender to verify the signed document. At regular intervals, the GNotary server creates message digests of its own logs and distributes them among other GNotary servers, thus making it virtually impossible to forge the chain of evidence that authenticates a submitted document.