Digital Contract Using Block Chaining and Elliptic Curve Based Digital Signature

摘要

Recently, a contract agreement or contract document was used as a legal requirement of the business deal. For securing the contract, authentication and encryption is necessary. In conventional contract, the contract owner (the sender) is authenticated by the client (the receiver). The authentication is conducted by verifying the owner's signature using human vision. It is shown that the conventional contract has drawback when it was used to conduct long distance business. Since conventional agreement is using only digital signatures, the sender of the contract documents can be authenticated but there is still problem because both parties cannot perform mutual authentication and it cannot resolve legal dispute. Therefore, a witness was required, to overcome the problems when legal dispute was occurred. For implementing the witness, block chaining is proposed. There are several works that have been proposed for realizing authentication, and one of them is using RSA proposed by Raji et al. Since RSA needs large complexity, then in this research, ECC and ECDSA is proposed. ECC and ECDSA is proposed because it has less complexity than RSA. Based on the experiment result, it is shown that legal dispute can be resolved and the security level of the proposed method is greater than RSA. Meanwhile, the complexity of ECDSA is less than digital signature based on RSA.