Research On Efficient And Practical E-cash Mechanism

With the development of information technology and e-commerce rapidly,electronic cash has become an ideal payment method because of the advantages of online payment.The research on secure,efficient and practical electronic cash is one of the key problem to be solved urgently in e-commerce transactions.It is the scientific basis for the development of electronic payment systems.It has important scientific and academic value and broad application prospects.However,the existing electronic cash protocols still have deficiencies in terms of specific algorithms,the adopted cryptosystem,electronic cash models,security performance,and formal analysis of the protocols.Aiming at the problem of privacy and practicability of electronic cash,this thesis focuses on the anonymity and divisibility of electronic cash.The main work and contributions are as follows:(1)In order to realize the privacy protection of users in the payment process,this thesis proposes a new electronic cash scheme based on ring signature,and analyzes the security and efficiency of the scheme.The scheme satisfies correctness,anonymity,balance,unreusability and traceability.This scheme utilizes the anonymity of ring signatures to protect the privacy of users during the transaction process.Technically,the user identity is hidden in a group,and thus no one can ensure the real payer for some payment.This scheme can identify double spending electronic coin,simultaneously improve the cost efficiency.(2)In order to simulate the payment in the realworld,the currency should be divided due to its practicability.Therefore,a concrete electronic cash scheme based on proxy signature is proposed in this thesis.In the withdrawal protocol,the escrow key is used to complete the issuance of electronic money and grant the user currency division rights.In the spending protocol,the verifiability of the proxy signature is used to convince the merchant that the currency spent by the user is legal.During the transaction,a unique transaction serial number is generated using the secret value,and at the same time,the arbitrary divisibility of electronic money is realized.The correctness,divisibility,unreusability,balance and traceability of E-cash scheme are analyzed.