Economical and secure: EcoSign — A post-quantum hash-based digital signature scheme

The emergence of quantum threats has significantly shaken our trust in traditional digital signature schemes. Hash-based signatures, a prominent technique in post-quantum cryptography, have garnered increasing attention in cryptographic research and practical applications. This is attributed to their minimal security assumptions, adaptability, parameterized implementations, and the provision of forward-secure constructions. However, the primary limitation of hash-based signatures lies in their larger key and signature sizes. This paper introduces the hash-based one-time signature scheme ”EcoSign”, an enhanced version of the Smart Digital Signature-one-time signature scheme. EcoSign achieves significant reductions in keypair and signature sizes while providing flexibility for trade-offs between signature size and creation time. The processes of the generation of keypair and signature and verification of the generated signature are thoroughly explained. Additionally, the paper incorporates an algorithm for compressing the scheme’s public key into a single value using the Merkle tree compression technique. Our scheme presents a 73% decrease in key size and an 82% decrement in signature size when compared to the widely adopted Winternitz one-time signature scheme. In comparison to the improved version of Winternitz’s scheme: WOTS+, EcoSign showcases impressive reductions with a 76% decrease in key size and a 79% reduction in signature size.