The Wikipedia article Trusted Timestamping states that we can timestamp data by publishing it's hash. Publishing can be done either independently or via a third-party publisher, as explained by ...
What are well respected Cryptographic Timestamping authorities utilizing more sophisticated than just PKI (RFC 3161) schemes, like Linked, Linked and signed, distributed hash trees (maybe P2P?), ...
I have an entity A sending a message to another, B. An encrypted message is signed with a timestamp TB, and then the whole thing is signed again with a new key and new timestamp TA. What i'm ...