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?), hybrid ?
Is there any good resource (better than googling, what does not give information about how well service is respected).
I would love to use Keyless Signatures (different thank PKI schemes), preferably remaining reliable if PKI would be compromised (e.g. Linked and signed, distributed, hybrid, etc).
I know about such interesting approach: http://www.guardtime.com/signatures/technology-overview/ , but I would like to used a few (for better reliability - to achieve tens of years reliability) different approaches.
Preferably those well respected timestamps to be legally respected (e.g. Securo "Conforms to EU and US federal standards)
