In _Applied Cryptography_ by Bruce Schneier, he refers to a system proposed by Tatsuaki Okamoto and Kazuo Ohta that meets the following criteria: Independance. The security of the digital cash is not dependant on any physical location. The cash can be transfered through a computer network. Security. The digital cash cannot be coppied and reused. Privacy (untraceability). The privacy of the users is protected; no one can trace the relationship between users and their purchases. Off-Line Payment. When a user pays for a purchase with electronic cash, the protocall between the user and the merchant is executed off-line. Transferability. The digital cash can be transfered to other users. Divisability. A piece of digital cash in a given amount can be subdivided into pieces of cash in smaller amounts. The reference given for this paper is as follows: T. Okamoto and K. Ohta,"Universal Electronic Cash," Advances in Cryptology--CRYPTO '91 Proceedings, Berlin: Springer-Verlag, 1992, pp. 324-337 Happy Hunting, -Chris. ______________________________________________________________________________ Christian Douglas Odhner | "The NSA can have my secret key when they pry cdodhner@indirect.com | it from my cold, dead, hands... But they shall pgp 2.3 public key by finger | NEVER have the password it's encrypted with!" cypherpunks WOw dCD Traskcom Team Stupid Key fingerprint = 58 62 A2 84 FD 4F 56 38 82 69 6F 08 E4 F1 79 11 ------------------------------------------------------------------------------ On Tue, 3 May 1994, Black Unicorn wrote:
So has anyone tried to solve the problem of double spending and the online requirement of digital cash?
It seems digitial cash is really only digital "check" right now as it must be verified at the bank before it can be show to be "valid."
Is there any way to take cash offline? Or is this merely the copy protection problem rehashed?
-uni- (Dark)