OFF-LINE ANONYMOUS ELECTRONIC MONEY

In off-line electronic money the merchant does not require to cooperate with the bank before accepting a coin from the user. In its place he can gather multiple coins Spent by users and Deposit them later with the bank. In standard this could be done off-line, i.e. the merchant could go to the bank with his storage media to switch e-cash for cash. On the other hand the merchant is certain that the user's e-coin will either be established by the bank, or the bank will be proficient to recognize and punish the cheating user. In this way a user is prohibited from spending the similar coin twice (double-spending). Off-line e-cash schemes too need to look after against cheating merchants, i.e. merchants that desire to deposit a coin twice (and then blame the user).

Using cryptography, unidentified e-cash was come in to existence by David Chaum. He used blind signatures to get unlink ability between extraction and spend transactions. In cryptography, e-cash generally refers to unidentified e-cash. Depending on the properties of the payment transactions, one difference between off-line and on-line e-cash. The first off-line e-cash system was planned by Chaum and Naor. Like the first on-line scheme, it is based on RSA blind signatures.