[rstuart4133]

I'm repeating what I said above, but just send yourself an gmail with the hash in the Subject. Gmail will kindly timestamp it and provide a DKIM signature. Publish the mail headers gmail includes in the signature (which includes the timestamp and subject, but not the contents), the signature itself, and a link to hashed the document and you're done.

[mjg59]

This is only true if Google never release old private keys for DKIM signatures, which various people have been campaigning for them to do in order to provide long-term deniability around DKIM-signed mails.

[rstuart4133]

> This is only true if Google never release old private keys for DKIM signatures, which various people have been campaigning for them to do in order to provide long-term deniability around DKIM-signed mails.

I didn't know. Thanks for the heads up.