A Patch Protocol for SHK Secret Transfer Scheme

Abstract

Saied Hosseini Khayat proposed a scheme (SHK scheme) in 2008 to transfer a secret from sender to receiver such that the receiver cannot decrypt the secret without the consent of a group of trustees. This scheme is simple and excellent since it does not require any key exchange among sender, receiver, or trustees. But there is a prob-lem in this scheme that the secret will be exposed when the private keys of the sender, receiver, and trustees are chosen improperly such that any one of some bad relations among the keys happens. In this paper, a patch protocol for the SHK scheme is presented such that the private keys are guaranteed to be chosen properly and the privacy of all private keys is also assured.