基于改进P2PKHCA脚本方案的比特币密钥更新机制

Key Update Mechanism in Bitcoin Based on Improved P2PKHCA Script Scheme

比特币是最成熟的公有链应用系统之一,用户密钥是比特币所有权确定过程的关键,比特币的安全由用户密钥的安全管理所保证,密钥的遗失会导致大量的用户资产流失,因此实现流失资产找回是亟待解决的问题。针对以上问题,提出了基于改进P2PKHCA(具有条件匿名的支付到公钥哈希)脚本方案的比特币密钥更新机制。首先,通过引入密钥生命周期和随机数改进P2PKHCA方案中的密钥生成算法,以解决其存在的密钥泄露问题;其次,提出两个新的操作符OP_KEYUPDATE和OP_TSELECTION来设计新的密钥更新脚本,以实现比特币系统的用户密钥更新;最后,基于密钥更新脚本构造两种密钥更新方案,使得密钥更新脚本适用于不同的密钥更新应用需求。对密钥更新机制进行的安全性分析和性能分析表明,所提机制在有效完成用户密钥更新的前提下,能够实现比特币系统中流失比特币的找回。

Bitcoin is one of the most mature public chain application systems,the user key is the critical factor to the process of determining the ownership of Bitcoin,the security of Bitcoin is guaranteed by the safe management of the user key,and the loss of the key will lead to the loss of a large number of user assets.So it is an urgent problem to recover the lost assets.This paper proposes a key update mechanism in Bitcoin based on the improved P2PKHCA(pay-to-public-key-hash-with-conditional-anonymity)script scheme to solve above problems.Firstly,the key generation algorithm in the P2PKHCA scheme is improved by introducing the key life cycle and random number to solve its key leakage problem.Secondly,the two new opcodes,OP_KEYUPDATE and OP_TSELECTION,are proposed to design the new key update script to realize the user key update of the Bitcoin system.Finally,two types of key update schemes based on the key update script are constructed to make the script suitable for the requirements of different key update applications.The security analysis and performance analysis of the key update mechanism show that the proposed mechanism realizes the recovery of lost Bitcoins in the Bitcoin system on the premise of the effective completion of update of user’s key.