Post Quantum Blockchain with Segregation Witness

Abstract

Blockchain is a very important technology and financial innovation since the birth of the Internet. It is an innovative and integrated application of many technologies, with the characteristics of open and transparent data, not easy to tamper with, easy to trace and so on. Its cryptographic security relies on asymmetric cryptography, such as ECC, RSA. However, with the surprising development of quantum technology, asymmetric cryptography schemes mentioned above would become vulnerable. Recently, some lattice-based blockchain systems have been proposed to be secure against attacks in the quantum era. Although these schemes have theoretical significance, it is unpractical in actual situation due to handling capacity. In this paper, aiming at tackling the critical issue of throughput, we proposed post quantum blockchain with segregation witness which can effectively the proportion of signatures in block size. Based on the hardness assumption of Short Integer Solution (SIS), we demonstrate that the proposed post quantum blockchain with segregation witness existential unforgeability against adaptive chosen-message attacks in the random oracle. As compared to the existing scheme, our scheme has better performance in handling capacity. As the underlying lattice problem is intractable even for quantum computers, our scheme would work well in the quantum age.