Title: Quantum resistant multi-signature scheme with optimal communication round: A Blockchain-based approach

Abstract: Blockchain is a decentralized network to increase trust, integrity, and transparency of transactions. With the exponential growth of transactions in the realm of Blockchain, especially in Bitcoin, Blockchain size increases as all transactions must be stored and verified. In Bitcoin, validating M of N transactions involves the necessity of M authentic signatures out of the total N transactions. This procedure is so time-consuming and needs a significant storage capacity. To address these issues, several multi signature schemes have been proposed, enabling users to interactively generate a common signature on a single message. Recently, some lattice based multi signature schemes have been presented to deal with the threats of quantum computers. However, none of them have met all desirable features of multi signature schemes like aggregate public key, low numbers of communication rounds, or resistant to quantum computers. Within this paper, we present a new multi signature scheme based on lattices, known as Razhims, that has aggregate public key, necessitates solely a single round of communication, and is resistant to quantum computers. In Razhims, the aggregate public key size and the final signature size are equal to the public key size and the final signature size of a standard signature respectively, and are independent of the number of signers.