It allows the user to register a SHA256 Hash on the block chain to quickly prove ownership of a document at a particular point in time.
The Hash is registered to the user that sends the transaction.

ETH Gas Station
  1. To register a file hash the Digital Notary fee is 0.005 ETH. The GAS cost for the transaction is 55,500 Gas @ 6 Gwei is $0.06
  2. To transfer ownership of file hash the Digital Notary fee is 0.025 ETH. The GAS cost for the transaction is 42,000 Gas @ 6 Gwei is $0.05

Yes. The user address that currently owns the file Hash can transfer ownership of the Hash to another user.

You can either paste a Hash in the text box or click the select file button to select a file on your computer.
The Hash of the selected file will be calculated and pasted in the text box. Then just press the Register Hash Button to register the hash.

Paste a Hash in the text box and click the get Hash Details button.
A list of the current owner and previous owners if applicable will be displayed.

  1. Paste the Hash you want to transfer in the text box.
  2. Paste the new user address in the second text box below.
  3. Make sure the active account is the same user account address that currently owns the Hash.
  4. Click the Change Hash Ownership Button.

No. You transact only with the smart contract and all the data is stored on the block chain and is therefore easily verifiable.

If a user wants to prove ownership of a particular document at the current point in time.
For example a patent application, property deed, employment contract, education certificate, etc.

ENS is the Ethereum Name Service. If the Host has registered their Ethereum Address with an ENS name, then type the ENS name and press the ENS button. Stayusb will query the ENS registry and if a record is found, it will automatically populate the Host Ethereum address.