Serial number

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Serial number from an identity document Seriennummer.JPG
Serial number from an identity document
Serial number on a semi-automatic pistol NumeroPistola.JPG
Serial number on a semi-automatic pistol
Serial number of a laptop computer Serial Number.jpg
Serial number of a laptop computer

A serial number is a unique identifier assigned incrementally or sequentially to an item, to uniquely identify it.

With reference to a given set of objects, a unique identifier (UID) is any identifier which is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. There are three main types of unique identifiers, each corresponding to a different generation strategy:

  1. serial numbers, assigned incrementally or sequentially
  2. random numbers, selected from a number space much larger than the maximum number of objects to be identified. Although not really unique, some identifiers of this type may be appropriate for identifying objects in many practical applications and are, with abuse of language, still referred to as "unique"
  3. names or codes allocated by choice which are forced to be unique by keeping a central registry such as the EPC Information Services.


Serial numbers need not be strictly numerical. They may contain letters and other typographical symbols, or may consist entirely of a character string.

In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language.

String (computer science) sequence of characters, data type

In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed. A string is generally considered a data type and is often implemented as an array data structure of bytes that stores a sequence of elements, typically characters, using some character encoding. String may also denote more general arrays or other sequence data types and structures.

Applications of serial numbering

Serial numbers identify otherwise identical individual units with many, obvious uses. Serial numbers are a deterrent against theft and counterfeit products, as they can be recorded, and stolen or otherwise irregular goods can be identified. Some items with serial numbers are automobiles, electronics, and appliances. Banknotes and other transferable documents of value bear serial numbers to assist in preventing counterfeiting and tracing stolen ones.

Vehicle identification number unique code including a serial number, used by the automotive industry to identify individual motor vehicles, towed vehicles, motorcycles, scooters and mopeds

A vehicle identification number (VIN) is a unique code, including a serial number, used by the automotive industry to identify individual motor vehicles, towed vehicles, motorcycles, scooters and mopeds, as defined in ISO 3779 and ISO 4030.

Banknote Form of physical currency made of paper, cotton or polymer

A banknote is a type of negotiable promissory note, made by a bank, payable to the bearer on demand. Banknotes were originally issued by commercial banks, which were legally required to redeem the notes for legal tender when presented to the chief cashier of the originating bank. These commercial banknotes only traded at face value in the market served by the issuing bank. Commercial banknotes have primarily been replaced by national banknotes issued by central banks.

Counterfeit copy which is represented as the original (said to be the same as Q1332286)

To counterfeit means to imitate something authentic, with the intent to steal, destroy, or replace the original, for use in illegal transactions, or otherwise to deceive individuals into believing that the fake is of equal or greater value than the real thing. Counterfeit products are fakes or unauthorized replicas of the real product. Counterfeit products are often produced with the intent to take advantage of the superior value of the imitated product. The word counterfeit frequently describes both the forgeries of currency and documents, as well as the imitations of items such as clothing, handbags, shoes, pharmaceuticals, aviation and automobile parts, watches, electronics, software, works of art, toys, and movies.

They are valuable in quality control, as once a defect is found in the production of a particular batch of product, the serial number will identify which units are affected.

Quality control Project management process making sure produced products are good

Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "A part of quality management focused on fulfilling quality requirements".

Serial numbers for intangible goods

Serial numbers may be used to identify individual physical or intangible objects (for example computer software or the right to play an online multiplayer game). The purpose and application is different. A software serial number, otherwise called product key, is usually not embedded in the software, but is assigned to a specific user with a right to use the software. The software will function only if a potential user enters a valid product code. The vast majority of possible codes are rejected by the software. If an unauthorised user is found to be using the software, the legitimate user can be identified from the code. It is usually not impossible, however, for an unauthorised user to create a valid but unallocated code either by trying many possible codes, or reverse engineering the software; use of unallocated codes can be monitored if the software makes an Internet connection.

Product key

A product key, also known as a software key, is a specific software-based key for a computer program. It certifies that the copy of the program is original. Activation is sometimes done offline by entering the key, or with software like Windows 8.1, online activation is required to prevent multiple people using the same key. Not all software has a product key, as some publishers may choose to use a different method to protect their copyright, or in some cases, such as free or open source software, copyright protection is not used.

Reverse engineering, also called back engineering, is the process by which a man-made object is deconstructed to reveal its designs, architecture, or to extract knowledge from the object; similar to scientific research, the only difference being that scientific research is about a natural phenomenon.

Internet Global system of connected computer networks

The Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing.

Other uses of the term

The term serial number is sometimes used for codes which do not identify a single instance of something. For example, the International Standard Serial Number or ISSN used on magazines and other periodicals, an equivalent to the International Standard Book Number (ISBN) applied to books, is serially assigned not to each individual copy but to an issue of a periodical. It takes its name from the library science use of the word serial to mean a periodical.

International Standard Book Number Unique numeric book identifier

The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.

Library science is an interdisciplinary or multidisciplinary field that applies the practices, perspectives, and tools of management, information technology, education, and other areas to libraries; the collection, organization, preservation, and dissemination of information resources; and the political economy of information. Martin Schrettinger, a Bavarian librarian, coined the discipline within his work (1808–1828) Versuch eines vollständigen Lehrbuchs der Bibliothek-Wissenschaft oder Anleitung zur vollkommenen Geschäftsführung eines Bibliothekars. Rather than classifying information based on nature-oriented elements, as was previously done in his Bavarian library, Schrettinger organized books in alphabetical order. The first American school for library science was founded by Melvil Dewey at Columbia University in 1887.

Certificates and certificate authorities (CA) are necessary for widespread use of cryptography. These depend on applying mathematically rigorous serial numbers and serial number arithmetic, again not identifying a single instance of the content being protected.

The RAF serial (XG900) on the Short SC.1 Short SC.1.png
The RAF serial (XG900) on the Short SC.1

Military and government use

The term serial number is also used in military formations as an alternative to the expression service number .[ citation needed ] In air forces, the serial number is used to uniquely identify individual aircraft and is usually painted on both sides of the aircraft fuselage, most often in the tail area, although in some cases the serial is painted on the side of the aircraft's fin/rudder(s). Because of this, the serial number is sometimes called a tail number.

In the UK Royal Air Force (RAF) the individual serial takes the form of two letters followed by three digits, e.g., BT308—the prototype Avro Lancaster, or XS903—an English Electric Lightning F.6 at one time based at RAF Binbrook. [1] During the Second World War RAF aircraft that were secret or carrying secret equipment had "/G" (for "Guard") appended to the serial, denoting that the aircraft was to have an armed guard at all times while on the ground, e.g., LZ548/G—the prototype de Havilland Vampire jet fighter, or ML926/G—a de Havilland Mosquito XVI experimentally fitted with H2S radar. Prior to this scheme the RAF, and predecessor Royal Flying Corps (RFC), utilised a serial consisting of a letter followed by four figures, e.g., D8096—a Bristol F.2 Fighter currently owned by the Shuttleworth Collection, or K5054—the prototype Supermarine Spitfire. The serial number follows the aircraft throughout its period of service.

In 2009, the U.S. FDA published draft guidance for the pharmaceutical industry to use serial numbers on prescription drug packages. [2] This measure is intended to enhance the traceability of drugs and to help prevent counterfeiting.

Serial number arithmetic


Serial numbers are often used in network protocols. However, most sequence numbers in computer protocols are limited to a fixed number of bits, and will wrap around after a sufficiently many numbers have been allocated. Thus, recently allocated serial numbers may duplicate very old serial numbers, but not other recently allocated serial numbers. To avoid ambiguity with these non-unique numbers, RFC   1982 "Serial Number Arithmetic", defines special rules for calculations involving these kinds of serial numbers.

Lollipop sequence number spaces are a more recent and sophisticated scheme for dealing with finite-sized sequence numbers in protocols.

See also


Related Research Articles

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In computer networking, the User Datagram Protocol (UDP) is one of the core members of the Internet protocol suite. The protocol was designed by David P. Reed in 1980 and formally defined in RFC 768. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol (IP) network. Prior communications are not required in order to set up communication channels or data paths.

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A software protection dongle is an electronic copy protection and content protection device. When conncted to a computer or other electronics, they unlock software functionality or decode content. The hardware key is programmed with a product key or other cryptographic protection mechanism and functions via an electrical connector to an external bus of the computer or appliance.

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Traitor tracing schemes help trace the source of leaks when secret or proprietary data is sold to many customers. In a traitor tracing scheme, each customer is given a different personal decryption key. (Traitor tracing schemes are often combined with conditional access systems so that, once the traitor tracing algorithm identifies a personal decryption key associated with the leak, the content distributor can revoke that personal decryption key, allowing honest customers to continue to watch pay television while the traitor and all the unauthorized users using the traitor's personal decryption key are cut off.)

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Aircraft registration registration and identification assigned to an individual aircraft by national aviation authorities

An aircraft registration is a code unique to a single aircraft, required by international convention to be marked on the exterior of every civil aircraft. The registration indicates the aircraft's country of registration, and functions much like an automobile license plate. This code must also appear in its Certificate of Registration, issued by the relevant National Aviation Authority (NAA). An aircraft can only have one registration, in one jurisdiction, though it is changeable over the life of the aircraft.

Many protocols and algorithms require the serialization or enumeration of related entities. For example, a communication protocol must know whether some packet comes "before" or "after" some other packet. The IETF RFC 1982 attempts to define "Serial Number Arithmetic" for the purposes of manipulating and comparing these sequence numbers.

In computer networking, a port is an endpoint of communication. Physical as well as wireless connections are terminated at ports of hardware devices. At the software level, within an operating system, a port is a logical construct that identifies a specific process or a type of network service. Ports are identified for each protocol and address combination by 16-bit unsigned numbers, commonly known as the port number. Inbound packets are received, and the port number in the header is used to decide which application is to be passed the packets.

United Kingdom military aircraft serial numbers

United Kingdom military aircraft serials refers to the serial numbers used to identify individual military aircraft in the United Kingdom. All UK military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry (AM), and its successor the Ministry of Defence (MoD), is used for aircraft operated by the Royal Air Force (RAF), Fleet Air Arm (FAA) and Army Air Corps (AAC). Military aircraft operated by government agencies and civilian contractors are also assigned serials from this system.

United States military aircraft serial numbers

In the United States, all military aircraft display a serial number to identify individual aircraft. These numbers are located on the aircraft tail, so they are sometimes referred to unofficially as "tail numbers". On the Northrop Grumman B-2 Spirit bomber, lacking a tail, the number appears on the nose gear door. Individual agencies have each evolved their own system of serial number identification. Aircraft serials are part of the Aircraft Visual Identification System, which also includes the aircraft's tail code and Modex.

United Kingdom aircraft test serials are used to externally identify aircraft flown within the United Kingdom without a full Certificate of Airworthiness. They can be used for testing experimental and prototype aircraft or modifications, pre-delivery flights for foreign customers and are sometimes referred to as "B" class markings.

United Kingdom aircraft registration

United Kingdom aircraft registration is a register and means of identification for British owned and operated commercial and private aircraft, they are identified by registration letters starting with the prefix G-.

Drug distribution is the process by means of which people get access to medication.