Using cryptography, ecash was introduced by David Chaum as an anonymous electronic cash system. He used blind signatures to achieve unlinkability between withdrawal and spend transactions. Depending on the properties of the payment transactions, one distinguishes between on-line and off-line electronic cash. The first off-line e-cash system was proposed by Chaum and Naor. Like the first on-line method, it is based on RSA blind signatures.
In the United States, only one bank implemented ecash, the Mark Twain bank and the system was dissolved in 1997 after the bank was purchased by Mercantile Bank, a large issuer of credit cards. Similar to credit cards, the system was free to purchasers, while merchants paid a transaction fee.
In Australia ecash was implemented by St.George Bank, but the transactions were not free to purchasers. In June 1998, ecash became available through Credit Suisse in Switzerland. It was also available from Deutsche Bank in Germany, Bank Austria, Finland's Merita Bank/EUnet, Sweden's Posten, and Den norske Bank of Norway.
See also 
- Chaum, D., Fiat, A., and Naor, M. 1990. Untraceable electronic cash. In Proceedings on Advances in Cryptology (Santa Barbara, California, United States). S. Goldwasser, Ed. Springer-Verlag New York, New York, NY, 319-327.
- DigiCash loses U.S. toehold
- Salonharju, Inkeri. "Elektra-projektin loppuraportti". Retrieved 2013-05-18.
- Järvinen, Petteri (1996). Internet - muutostekijä. Werner Söderström Osakeyhtiö. ISBN 951-0-21704-2.
- Schneier, Bruce. Applied Cryptography, Second Edition, John Wiley & Sons, 1996. ISBN 0-471-11709-9 (Chapter 6.4)
- Richard A. Mollin: RSA and Public-key Cryptography. p. 143-148. 2002, ISBN 1-58488-338-3, ISBN 978-1-58488-338-8.
- Goldwasser, S. and Bellare, M. "Lecture Notes on Cryptography". Summer course on cryptography, MIT, 1996-2001. pp. 233.