Site: Crypto Public Notary,
http://www.cryptopublicnotary.comWith the recent OKCoin/Roger Ver contract issues I decided to try and tackle the problem of digital document provenance.
What it is:Digital Document Provenance is the ability to prove a document existed at a specific point in time. Using an address derived from the cryptographic hash of a digital file, any Bitcoin transaction to that address serves as a public timestamp.
Example: You and I draft a contract. We add our GPG signatures to the document and obtain the SHA256 hash of the file. Using that hash as a Bitcoin private key we can derive a public key and, therefore, an address. If a single bit in the file changes, so does the Bitcoin address.
One, or both, of us send a dust transaction to that address, foreve
r recording it in the block chain. Anyone is able to verify that document is linked to that address, and therefore it existed at that point in time. Simply take the SHA256 hash of the file and generate the matching public key/address.
How it works:Choose any digital file. Our service takes the SHA256 hash of the file and uses that value as a Bitcoin private key. Effectively, the file is acts like a pass phrase.
Next, we provide you the Bitcoin address for that key pair and a WIF private key.
Then, you send a small amount of bitcoin to the address. The transaction in the block chain serves as a timestamp and (optionally) you sweep the private key, reclaiming your bitcoin.
Finally, the service runs completely in the browser. You retain full ownership of your digital documents.
This service will remain free, forever. Down the round I may expand into additional services
TLDR: We calculate a hash of your file. We use that to seed a Bitcoin keypair/address. You send some dust to address. That transaction/address serves as proof of existence for that document at the time stamp recorded on the block chain.
