ENR DigiSig: an efficient post-quantum digital signature scheme using polar codes

Digital signatures play a vital role in data security as they provide authenticity and non-repudiation of digital data. Code-based digital signatures are in high demand as quantum computers are extremely effective at breaking widely used digital signatures. The Courtois–Finiasz–Sendrier (CFS) scheme is one of the most popular code-based digital signature schemes. However, it has some disadvantages, such as a large public key size and poor signing efficiency. To address this issue, we construct a digital signature scheme named ENR DigiSig (Ekta Narwal and Rupali Digital Signature) using polar codes with several characteristics such as small signature size, low signing time, and high signing efficiency. Here, the hash of a shorter length is used in a specific way; then, padding is done to the hash output so that the result can be decoded. For this study, we have selected a fixed polar code rate of 0.5 and a blocklength of \(N=2^{n};n\leqslant 4\). According to the experimental results, more than 96% of the signatures are generated successfully.