Personally identifiable information

In information security and privacy, personally identifiable information or personally identifying information (PII) is any piece of information which can potentially be used to uniquely identify, contact, or locate a single person.

Although the concept of PII is ancient, it has become much more important as information technology and the Internet have made it easier to collect PII, leading to a profitable market in collecting and reselling PII. PII can also be exploited by criminals to stalk or steal the identity of a person, or to plan a person's murder or robbery, among other crimes. As a response to these threats, many website privacy policies specifically address the collection of PII, and lawmakers have enacted a series of legislation to limit the distribution and accessibility of PII.

Examples
Items which might be considered PII include, but are not limited to, a person's:


 * Full name (if not common)


 * Social security number


 * Telephone number


 * Street address


 * E-mail address


 * IP address (in some cases)


 * Vehicle registration plate number


 * Driver's license number


 * Face, fingerprints, or handwriting


 * Credit card numbers

Information that is not generally considered personally identifiable, because many people share the same trait, include:


 * First or last name, if common


 * Country, state, or city of residence


 * Age, especially if non-specific


 * Gender or race


 * Name of the school they attend or workplace


 * Grades, salary, or job position


 * Criminal record

When a person wishes to remain anonymous, descriptions of them will often employ several of the above, such as "a 34-year-old black man who works at Target". Note that information can still be private, in the sense that a person may not wish for it to become publicly known, without being personally identifiable. Moreover, sometimes multiple pieces of information, none of which are PII, may uniquely identify a person when brought together; this is one reason that multiple pieces of evidence are usually presented at criminal trials. For example, there may be only one Inuit person named Steve in the town of Lincoln Park, Michigan.

Related laws
Recently lawmakers have paid a great deal of attention to protecting a person's PII. One of the primary focuses of the Health Insurance Portability and Accountability Act (HIPAA), is to protect a patient's PII.

U.S. lawmakers have paid special attention to the social security number because it can be easily used to commit identity theft. The Social Security Number Protection Act of 2005 and Identity Theft Prevention Act of 2005 each seek to limit the distribution of an individual's social security number.

On the other hand, many businesses see this increasing load of legislation as excessive, an unnecessary expense, and a barrier to progress. The increasing complexity of the laws might force companies to consult a lawyer just to engage in simple business practices such as server logging, user registration, and credit checks. Some have predicted such measures may inhibit the industry as a whole, lowering wages and creating a barrier to entry. For this reason, a number of privacy laws stress the "acceptable uses" of PII.