基于中间人的区块链混币机制

Coin mixing mechanism in blockchain based on intermediator

混币机制是区块链隐私保护技术之一,目前面临效率低下、安全性不足、容易遭受拒绝服务攻击等问题,因此提出了一种基于中间人的区块链混币机制,称为IMShuffle。该混币机制首先对混币交易的参与者随机分组,每个小组成员都需要从小组中选择一位参与者作为中间人发送自己的输出地址,这些中间人将接收到的输出地址发送给小组的最后节点;然后运用多层加密的思想完成小组间最后节点输出地址的传递;最后一组的最后节点接收到所有参与者的输出地址完成混币交易。经过实验分析表明,IMShuffle在参与者达到70名时混币时间仅11 s,与CoinShuffle、TTShuffle机制的运行时间相比,大大提升了混币交易的效率,缩短了混币交易消耗的时间,同时保护了交易过程中参与者的隐私,并降低了遭受拒绝服务攻击的风险。

Coin mixing mechanism is one of the privacy protection technologies of the blockchain, which faces some issues such as low efficiency, insufficient security and DoS attacks. Therefore, this paper proposed a blockchain coin mixing mechanism based on intermediator, called IMShuffle. Firstly, it divided the participants in the coin mixing transaction into different groups at random. Each group member took the initiative to broadcast and sent its own output address to its intermediator, these intermediators sent the received output address to the last node of the group. Then it used the idea of multi-layer encryption to complete the transfer of the output address of the last node between the groups. The last node of the last group received the output addresses of all participants to complete the coin mixing transaction. Experimental analysis shows that the IMShuffle has a mixing time of only 11 s when the participants reach 70. Compared with the running time of the CoinShuffle and TTShuffle mixing mechanism, it greatly improves the efficiency of the mixing transaction and shortens the time of mixing transaction. It protects the privacy of participants in the transaction process and reduces the risk of DoS attacks.