A New Code-Based Designated Verifier Signature Scheme

Designated verifier signature (DVS) scheme allows the verifier to verify the signature of a message but prevents from transferring the conviction to any third party. This scheme is useful in circumstances where authenticity, signer ambiguity, and signer's privacy are simultaneously needed in various applications such as electronic voting, call for tenders, etc. Most of the existing DVS schemes are based on the hard problems in number theory such as integer factorization or the discrete log problem. The construction of a large-scale quantum computer would break those schemes. So, the National Institute of Standards and Technology Internal Report recommends to develop cryptographic systems that are secure against both the quantum and the classical computers. One such promising alternative to number theoretic cryptography is code-based cryptography. This paper analyzes the code-based strong designated verifier schemes proposed in 2016 by Ren et al and Koochak Shooshtari et al and shows that these schemes do not have non-transferability which is the essential feature of a DVS scheme. Further, the paper proposed a DVS scheme built on syndrome decoding, a hard problem in coding theory, and proves its security properties such as unforgeability and non-transferability in the random oracle model.