In security

Security

Security is the degree of protection against danger, damage, loss, and crime. Security as a form of protection are structures and processes that provide or improve security as a condition. The Institute for Security and Open Methodologies in the OSSTMM 3 defines security as "a form of protection...

, piggybacking refers to when a person tags along with another person who is authorized to gain entry into a restricted area, or pass a certain checkpoint. The act may be legal or illegal, authorized or unauthorized, depending on the circumstances. However, the term more often has the connotation of being an illegal or unauthorized act.

To describe the act of an unauthorized person who follows someone to a restricted area without the consent of the authorized person, the term tailgating is also used. "Tailgating" implies without consent (similar to a car tailgating

Tailgating

Tailgating is the practice of driving on a road too close to the vehicle in front, at a distance which does not guarantee that stopping to avoid collision is possible...

 another vehicle on the freeway), while "piggybacking" usually implies consent of the authorized person.

Piggybacking came to the public's attention particularly in 1999, when a series of weaknesses were exposed in airport security. While a study showed that the majority of undercover agents attempting to pass through checkpoints, bring banned items on planes, or board planes without tickets were successful, piggybacking was revealed as one of the methods that was used in order to enter off-limits areas.

Methods

Piggybackers have various methods of breaching security. These may include:

• Surreptitiously following an individual authorized to enter a location, giving the appearance of being legitimately escorted
• Joining a large crowd authorized to enter, and pretending to be a member of the crowd that is largely unchecked
• Finding an authorized person who either carelessly disregards the law
  Law
  Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...
  
   or the rules of the facility, or is tricked into believing the piggybacker is authorized, and agreeably allows the piggybacker to tag along

Tailgating can be regarded as one of the simpler forms of social engineering

Social engineering (security)

Social engineering is commonly understood to mean the art of manipulating people into performing actions or divulging confidential information...

.

Reasons

The reasons for piggybacking can be the following:

• avoid paying a required fee;
• gaining access to an area prohibited to the piggybacker;
• to avoid sign-in delay, presenting identification, even if the person is eligible for access.
• a person may have forgotten or lost their access key, pass or token.
• People may also hold doors open for others to be polite.

Levels of security

Depending on the type of location, levels of security vary. Some checkpoints have very high levels in which all individuals are checked, regardless, and therefore are capable of preventing nearly all piggybacking. These may include those with intense human surveillance

Surveillance

Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...

 or three-dimensional computer vision detection systems, such as those at airports

Airport security

Airport security refers to the techniques and methods used in protecting airports and aircraft from crime.Large numbers of people pass through airports. This presents potential targets for terrorism and other forms of crime due to the number of people located in a particular location...

, apartment

Apartment

An apartment or flat is a self-contained housing unit that occupies only part of a building...

s with doormen

Doorman (profession)

A doorman is an individual hired to provide courtesy and security services at a residential building or hotel. They are particularly common in urban luxury highrises. At a residential building, a doorman is responsible for opening doors and screening visitors and deliveries...

, or turnstile

Turnstile

A turnstile, also called a baffle gate, is a form of gate which allows one person to pass at a time. It can also be made so as to enforce one-way traffic of people, and in addition, it can restrict passage only to people who insert a coin, a ticket, a pass, or similar...

s.

Others, with weaker controls, are more likely to allow such a breach. These may include unmanned entries with the use of a card or entry code, or locations where an attendant can be easily distracted by other duties, such as checking others.

High-security facilities typically use secure revolving door

Revolving door

A revolving door typically consists of three or four doors that hang on a center shaft and rotate around a vertical axis within a cylindrical enclosure. Revolving doors are energy efficient as they prevent drafts, thus preventing increases in the heating or cooling required for the building...

s or "mantrap

Mantrap

Mantraps are physical security devices or constructions designed to entrap a human on purpose.-Historical usage:Historically, mantraps were mechanical devices for catching poachers and trespassers. The devices have taken many forms, the most usual being like a large foothold trap, the steel springs...

s" to prevent tailgating. Revolving doors may have a smaller segment space between the door leaves, and can be fitted with electronic sensors using infrared beams and computer vision systems which cause the door's powered rotation to reverse if more than one person is detected in a segment space. Alternatively, a Gatekeeper system can be used which applies photonics technology to measure the volume occupied by one person; two persons occupy a larger space and as such are not allowed to enter.