SECURE MULTI-SIGNATURE PROTOCOL TO COUNTER TRANSACTION MALLEABILITY IN DEFI

Abstract

In blockchain-based Decentralised Finance (DeFi) protocols, signatures play a vital role in ensuring the security and integrity of transactions and smart contracts. However, weaknesses in existing signature schemes make them vulnerable to malleability attacks (MA), where an attacker can alter the transaction ID (TxId) without changing the transaction’s content or validity. To address this, we propose an advanced multi-signature scheme (MSS) that integrates unmalleable transaction implementations as a supplementary signature mechanism. In MSS, both owners and block producers collaboratively generate joint signatures, enhancing efficiency while ensuring stronger protection against malleability. Although the method is complex and time-intensive, it has been adapted to blockchain environments with additional optimisations, such as hashbased execution of intermediate transactions, to guarantee complete resistance to malleability attacks. Experimental results from testbed simulations highlight that MSS offers improved scalability and achieves a 15% higher resistance rate against attack success compared to baseline approaches.