Efficient off-line E-cash scheme

E-cash is essentially a string of bit sequence,which is easy to be copied.The key concern of E-cash is how to effectively prevent E-cash from being double-spent under preconditions that a legal user's anonymity is well protected.An off-line E-cash scheme basedon RSA blind signature is presented.The technology oftwi-symmetrical encryptionemploying double keys is adopted.It guarantees anonymity of theusers who spend an E-cashpiece onlyonce.Besides,the userwho has spent thesamepiece of E-cash twiceare detected at a considerable probability.The cut and choose scheme is improved to decrease computing.Finally,the analysis of security and the demonstration of fairness are given.