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Re: Digital Cash

In _Applied Cryptography_ by Bruce Schneier, he refers to a system 
proposed by Tatsuaki Okamoto and Kazuo Ohta that meets the following 
	Independance. The security of the digital cash is not dependant 
on any physical location. The cash can be transfered through a computer 
	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
[email protected]	     | 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)