SmartNDA: Realizing Unilateral Non Disclosure Agreements using a Bitcoin Penalty [F07-107]
Easwar Vivek Mangipudi. Krutarth Rao, Aniket Kate
We study the problem of realizing a unilateral Non Dis- closure Agreement (NDA) in a two user Sender-Receiver setting where the trust between the two users is enforced using a Bitcoin smart contract. The NDA is time-bound and any dishonesty on the part of the receiver, by reveal- ing the non-disclosable document, is penalized through the loss of Bitcoins. A watermarked version of the docu- ment is transferred to the receiver, who during the proto- col, uses his Signing-Key to obtain the document. In case of a dishonest disclosure of the document by the receiver, the receiver’s signing key gets revealed to the sender who has access to the revealed document. The obtained sign- ing key is used by the sender to penalize the receiver by transferring the funds from a previously committed Time- Locked Bitcoin Deposit. In this work, we design a pro- tocol named SmartNDA which realizes the solution and analyze it by studying the different modules necessary for its implementation. We proceed to argue the security of the protocol in-terms of Universal Composability and then report the results of the implementation of the pro- tocol. From the performance evaluation, we observe that the designed protocol is easy to deploy and fast to run.