Title:	Countermeasures Against Government-Scale Monetary Forgery
Authors:	Alessandro Acquisti, Nicolas Christin, Bryan Parno and Adrian Perrig
Publication Date:	December 3, 2007
Full Report:	CMU-CyLab-07-016 (.pdf)

Abstract

Despite cryptographic breakthroughs in the area of digital cash and the rapid advance of information technology, physical cash remains the dominant currency: it is easy to use and its exchanges are largely independent of computing devices. However, physical cash is vulnerable to rising threats - such as largescale, government-mandated forgeries - that digital cash may protect against more effectively. We study mechanisms to combine physical cash with digital cash to remove their respective shortcomings and obtain their combined advantages. We discuss initialmechanisms, ranging fromcryptographic signatures embedded in 2-D barcodes, to physical one-way functions coupled with online verification systems, and examine their cost and benefit trade-offs.