http://u4embjw2uzwpdubgm72ywbmixte4kqgwurc4r4rp6elhlokutdfsy4id.onion/about
About the Service This service provides a straightforward implementation of the Proof of Existence concept on the Gridcoin blockchain. You can securely and anonymously store proof of the existence of any of your documents (e.g. images, videos, documents, binaries) in the decentralized ledger without revealing the actual content of the document.