Double-spending

Double-spending is a failure mode of digital cash schemes, when it is possible to spend a single digital token twice. Since, unlike physical token money such as coins, electronic files can be duplicated, and hence the act of spending a digital coin does not remove its data from the ownership of the original holder,^[1] some other means is needed to prevent double-spending.

This is usually implemented using an on-line central trusted third party that can verify whether a token has been spent.^[1] This normally represents a single point of failure from both the technical and trust viewpoints. However, a number of distributed systems for double spending prevention have been proposed.^[2][3] Bitcoin is an example of a digital cash system that uses a distributed system of this sort.

See also

• Blind signature

References

1. ^ ^{a b} Mark Ryan. "Digital Cash". School of Computer Science, University of Birmingham. http://www.cs.bham.ac.uk/~mdr/teaching/modules06/netsec/lectures/DigitalCash.html. Retrieved 2010-07-12. 
2. ^ Jaap-Henk Hoepman (2008). "Distributed Double Spending Prevention". arXiv:0802.0832v1 [cs.CR]. 
3. ^ Osipkov, I.; Vasserman, E. Y.; Hopper, N.; Kim, Y. (2007). Combating Double-Spending Using Cooperative P2P Systems. pp. 41. doi:10.1109/ICDCS.2007.91.  edit