Blockchain Coin Mixing Scheme Based on Homomorphic Encryption
Coin mixing is important for protecting transaction privacy and realizing transaction unlinkability.However,hundreds of bytes of space overhead is necessary because of its verification process with pedersen commitment,which severely reduces its usability.A new coin mixing scheme is proposed by using SM2 algorithm,homomorphic encryption and stealth address technolo-gy in this paper.The on-chain transaction information is completely hide by using EC-ElGamal partially homomorphic encryption technology to encrypt the transaction value.Then the confidential transaction is sent to one-time stealth addresses after twice ve-rification and once re-randomization,thus breaking the connection between the payer and payee of the transaction to achieve un-linkability and untraceability of the transaction.This scheme can severely increase the privacy degree of transaction and transac-tion per second(TPS)while 82.25%reduction in the size of one transaction is achieved.At the same time,it enhances the resis-tance to analysis attacks,key replay attacks and sybil attacks.