An automated sales suppression device or zapper is a software program that falsifies the electronic records of point of sale (POS) systems for the purpose of tax evasion.
Most jurisdictions levy a sales tax or a value added tax on commercial transactions such as sales in stores or food served in a restaurant. These transactions are now most often recorded by a POS system rather than a mechanical cash register. The POS system records are generally not alterable by the operator and are used as the basis of tax assessments and audits by tax authorities.
Because POS systems are increasingly designed as general purpose computers (as of 2008, 85% worldwide were reported to run Microsoft Windows),[1] arbitrary software can be run on them. A "zapper" is a software program, often run untraceably from a USB flash drive, that accesses the POS system records and allows the owner of a business to alter the records so as to make it credibly appear that fewer transactions have occurred than has actually been the case. This reduces the tax burden on the business, which is generally proportional to the volume of the transactions.
The use of zappers is illegal and may be subject to criminal penalties. However, according to a 2008 New York Times report, governments worldwide have yet to find effective means of prosecuting their use.[1] A European Union committee on cash register fraud has been established, and legislation mandating tamper-proof POS systems has been proposed in Germany in 2008 and introduced in Quebec on September 1st, 2010.[1]