Optimizing Bitcoin Privacy: Securing Mixing Scheme via Multisignature

Bitcoin mixing operations are essential for enhancing transaction privacy by obfuscating the link between transaction inputs and outputs. However, the transparency of blockchain transactions presents significant privacy risks, as transaction details are publicly recorded. To address these challenges, Bitcoin mixing operations are crucial for obfuscating the link between transaction inputs and outputs, thereby enhancing transaction privacy. Whereas, current mixing approaches are limited by several issues, including reliance on trusted third-party services, vulnerability to forgery by malicious participants, and suboptimal efficiency. In response to these challenges, we propose a decentralized Bitcoin mixing scheme named CoinMixMultiSig (CMMS). This scheme designs a two-round collaborative public address generation process, allowing participants to jointly create a public address and send their Bitcoin efficiently to this address before signing. This approach mitigates fraud risks, such as participants dropping out during the mixing process or maliciously altering transaction data, which could lead to asset loss. To enhance security and efficiency, CMMS incorporates a multi-signature mechanism that reduces the overall signature size. The multi-signature mechanism reduces computational and communication overhead, enhancing efficiency and practicality for real-world use. A rigorous security analysis demonstrates that CMMS ensures unforgeability and effectively resists rogue key attacks, providing a reliable and secure option for Bitcoin transactions.