Ecash
Encyclopedia
Using cryptography, ecash was introduced by David Chaum
David Chaum
David Chaum is the inventor of many cryptographic protocols, including blind signature schemes, commitment schemes, and digital cash. In 1982, Chaum founded the International Association for Cryptologic Research , which currently organizes academic conferences in cryptography research...

 as an anonymous electronic cash
Electronic money
Electronic money is money or scrip that is only exchanged electronically. Typically, this involves the use of computer networks, the internet and digital stored value systems...

 system. He used blind signature
Blind signature
In cryptography a blind signature as introduced by David Chaum is a form of digital signature in which the content of a message is disguised before it is signed. The resulting blind signature can be publicly verified against the original, unblinded message in the manner of a regular digital...

s 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
Electronic cash
Electronic cash is the debit card system of the German Central Credit Committee, the association which represents the top German financial interest groups. Usually paired with a checking account, cards with an Electronic Cash logo are only handed out by proper credit institutions...

. 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 signature
Blind signature
In cryptography a blind signature as introduced by David Chaum is a form of digital signature in which the content of a message is disguised before it is signed. The resulting blind signature can be publicly verified against the original, unblinded message in the manner of a regular digital...

s.

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.

"ecash" was a trademark of DigiCash
DigiCash
DigiCash Inc. was a pioneering electronic currency corporation founded by David Chaum in 1990. DigiCash transactions were unique in that they were anonymous due to a number of cryptographic protocols developed by its founder...

, which went bankrupt in 1998, and was sold to eCash Technologies, which was acquired by InfoSpace in 2002.

Literature

  • 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 1584883383, 9781584883388.
  • Goldwasser, S.
    Shafi Goldwasser
    Shafrira Goldwasser is the RSA Professor of electrical engineering and computer science at MIT, and a professor of mathematical sciences at the Weizmann Institute of Science, Israel.-Biography:...

     and Bellare, M.
    Mihir Bellare
    Mihir Bellare is a cryptographer and professor at the University of California, San Diego. He has published several seminal papers in the field of cryptography , many coauthored with Phillip Rogaway. Bellare has published a number of papers in the field of Format-Preserving Encryption...

     "Lecture Notes on Cryptography". Summer course on cryptography, MIT, 1996-2001. pp. 233.

External links

  • "Detecting Double-Spending" -(Hal Finney
    Hal Finney (cypherpunk)
    Hal Finney is a developer for PGP Corporation, and was the 2nd developer hired after Phil Zimmerman. In his early career, he is credited as lead developer on several console games...

    's introduction to Chaumian digital cash)
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