opencoin: Open Source Electronic Cash

Opencoin describes itself as open source electronic cash and the opencoin project implements "digital cash". The system gives minting software, wallet software and everything that is necessary to have a system for anonymous electronic transactions. It can be used for vouchers, online payments, complementary currencies etc. The SourceForge mail archives can be found here and a sample user interface is provided here. opencoin defines standards and provides an implementation around the blind-signature system as invented by David Chaum, known as electronic cash / digicash. The software and specifications are opensource under a GPL License. For further information, please see:

"Extensions to Chaum's Blind Signature Scheme and OpenCoin Requirements"
A.W. Dent, K.G. Paterson and P.R. Wild
Information Security Group
Royal Holloway, University of London
February 27, 2008

Section 2 of this document gives an overview of the Chaum on-line e-cash scheme that makes use of blind RSA signatures. Section 3 outlines some extensions of the basic Chaum scheme that could be of use in the OpenCoin project. Section 4 discusses future requirements of the OpenCoin project and how they might be met.


"Preliminary Report on Chaum's Online E-Cash Architecture"
A. W. Dent, K. G. Paterson, and P. R. Wild
Information Security Group
Royal Holloway, University of London
February 28, 2008

This report discusses the security of Chaum's online e-cash architecture. This architecture can be used with an arbitrary blind signature scheme to give an anonymous e-cash system. This should be regarded as a preliminary report after a short period of research.

I find it interesting that the working group poses some very important legal questions and then progress mysteriously seems to slow. The opencoin project was originally funded by the lda, run by the open.coop, in cooperation with the Queen Mary University of London and Royal Holloway, University of London.