Identity theft is a criminal act where an individual's personal information is used fraudulently by an impostor for financial or legal benefits. With the rise in the transmission of personal information over the Internet, identity theft increased markedly between 1998 and 2001.

On May 4, 2009, the U.S. Supreme Court limited the ability of the federal government to use identity-theft laws to prosecute undocumented workers, to those cases in which the undocumented worker is aware that his or her social security belongs to someone else.New York Times: Supreme Court Rules Against Government in Identity-Theft Case (May 4, 2009)

A wide variety of laws and statutes protecting identity theft have been enacted at the federal and state levels. The earliest was the Identity Theft and Assumption Deterrence Act of 1998, enacted as P.L. 105-318 on October 30, 1998.LLRX: Identity Theft: Outline of Federal Statutes and Bibliography of Select Resources (February 7, 2006) Intended originally to defend consumers against the costs and damages of specific identity theft, the laws increasingly have been used to prosecute illegal immigrants who use false social security numbers to get employment.New York Times: Supreme Court Rules Against Government in Identity-Theft Case (May 4, 2009)

On May 4, 2009, the U.S. Supreme Court limited the ability of prosecutors of undocumented aliens to use identity theft laws. Prosecutors may only use that set of laws in cases in which the defendant is fully aware that the social security number or other identification he or she is using belongs to another person.LLRX: Identity Theft: Outline of Federal Statutes and Bibliography of Select Resources (February 7, 2006) New York Times: Supreme Court Rules Against Government in Identity-Theft Case (May 4, 2009)

Common forms of identity theft include the using of another's social security number to apply for jobs or other benefits; the use of personal information to open fraudulent lines of credit; or the providing of another's information in the course of an arrest.

A large industry has arisen surrounding the prevention of identity theft. Consumers can subscribe to credit report monitoring services or place a freeze on their credit report so that no new lines of credit can be opened.

The FBI alleges that members of an identity theft ring broke into the computer databases of about 50 schools in Puerto Rico, stealing birth certificates and social security numbers which they then sold to illegal immigrants.CBS11: FBI: Thousands Of P.R. Kids Victims Of ID Theft (March 31, 2009)

Seven suspects have been arrested and one more is being sought; some of those arrested are illegal immigrants from the Dominican Republic. The social security numbers and birth certificates were sold as a package for up to $250 each, in several states including Texas, Alaska and California.CBS11: FBI: Thousands Of P.R. Kids Victims Of ID Theft (March 31, 2009)