Using Ciphertext Policy Attribute Based Encryption for Verifiable Secret Sharing

Threshold secret sharing schemes are used to divide a given secret by a dealer in parts such that no less than the threshold number of shareholders can reconstruct the secret. However, these schemes are susceptible to the malicious behavior of a shareholder or a dealer. To prevent such attacks, it is necessary to make a provision for verification of the integrity of the shares distributed by the dealer. Such verification would ensure fair reconstruction of the secret. In this paper, we present a novel approach for verifiable secret sharing wherein the dealer and the shareholders are not assumed to be honest. Our proposed scheme uses attribute based encryption (ABE) to provide verifiability and for the semantically correct reconstruction of the secret. We call the new protocol as AB-VSS (Attribute Based Verifiable Secret Sharing).