Secure untraceable off-line electronic cash system

Eslami and Talebi (2011) [25] proposed an untraceable electronic cash scheme and claimed that their scheme protects the anonymity of customers, detects the identity of double spenders and provides the date attachability of coins to manage the bank database. In this paper, illustrating Eslami and Talebi’s scheme, as one of the latest untraceable electronic cash schemes, and showing its weaknesses (in fulfilling the properties of perceptibility of double spender, unforgeability and date attainability of coins) and its faults (related to exchange protocol), we propose a new untraceable electronic cash scheme which is immune to the weaknesses of the former. Our scheme contains anonymity, double-spending detection, unforgeability and date attachability properties and prevents forging. To do this, we described a special construction which injects the expiration date and the identity of the customer onto the coin and detects the identity in the case of double spending. Lastly, we show that the efficiency of our scheme is comparable with other schemes.