A Publicly Verifiable and Cheating Resistant Secret Sharing Based on Public Key Cryptosystem and Hash Function

Abstract

Sensitive data kept in a single information-bearer is more vulnerable to attack. Due to a single point of failure, it could be easily accessible or modifiable by an unauthorized user. To provide security to sensitive data against illegal access or alteration, several secret sharing techniques have been proposed. In a (k, n) threshold secret-sharing technique, n shares of the secret has to be distributed to n participants. And at the end, at least k out of n shares have to be collaborated to reveal the true secret. The beauty of this scheme is that collaboration of any shares less than k will not be able to reveal any kind of information regarding the secret. But, what will be the scenario if the shareholders are dishonest or some attacker is trying to hamper the secrecy of the secret by providing wrong information? So, to verify the correctness of the shared information, the verifiable property is added to the secret sharing, which is known as Verifiable secret sharing (VSS). Secret verification and cheater recognition are the two most popular features of this mechanism. The first one verifies the correctness of the secret and the second one helps to identify the cheater who has provided the wrong share. In our recent work, a publicly verifiable secret sharing technique is proposed, which can recognize the malicious participants or dishonest coordinator. The resistance of our proposed scheme towards the different types of attacks has been shown in the security analysis in this paper.