In the

software development process In software engineering, a software development process is a process of dividing software development work into smaller, parallel, or sequential steps or sub-processes to improve design, product management. It is also known as a software devel ...

, a reference implementation (or, less frequently, sample implementation or model implementation) is a program that implements all requirements from a corresponding specification. The reference implementation often accompanies a

technical standard A technical standard is an established norm or requirement for a repeatable technical task which is applied to a common and repeated use of rules, conditions, guidelines or characteristics for products or related processes and production methods, ...

, and demonstrates what should be considered the "correct" behavior of any other implementation of it.

Characteristics and examples

Reference implementations of algorithms, for instance

cryptographic algorithm In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can deci ...

s, are often the result or the input of

standardization Standardization or standardisation is the process of implementing and developing technical standards based on the consensus of different parties that include firms, users, interest groups, standards organizations and governments. Standardization ...

processes. In this function they are often dedicated to the

public domain The public domain (PD) consists of all the creative work A creative work is a manifestation of creative effort including fine artwork (sculpture, paintings, drawing, sketching, performance art), dance, writing (literature), filmmaking, ...

with their

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

public domain software Public-domain software is software that has been placed in the public domain, in other words, software for which there is absolutely no ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, ...

. Examples are the first CERN's httpd,

Serpent Serpent or The Serpent may refer to: * Snake, a carnivorous reptile of the suborder Serpentes Mythology and religion * Sea serpent, a monstrous ocean creature * Serpent (symbolism), the snake in religious rites and mythological contexts * Serp ...

cipher,

base64 In computer programming, Base64 is a group of binary-to-text encoding schemes that represent binary data (more specifically, a sequence of 8-bit bytes) in sequences of 24 bits that can be represented by four 6-bit Base64 digits. Common to all bina ...

variants, and

SHA-3 SHA-3 (Secure Hash Algorithm 3) is the latest member of the Secure Hash Algorithm family of standards, released by NIST on August 5, 2015. Although part of the same series of standards, SHA-3 is internally different from the MD5-like struct ...

. The

Openwall Project The Openwall Project is a source for various software, including Openwall GNU/*/Linux (Owl), a security-enhanced Linux distribution designed for servers. Openwall patches and security extensions have been included into many major Linux distribut ...

maintains a list of several algorithms with their reference

in the public domain. A reference implementation may or may not be production quality. For example, the Fraunhofer reference implementation of the

MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio developed largely by the Fraunhofer Society in Germany, with support from other digital scientists in the United States and elsewhere. Origin ...

standard usually does not compare favorably to other common implementations, such as

LAME Lame or LAME may refer to: Music * "Lame" (song) by Unwritten Law * ''Lame'' (album) by Iame People * Ibrahim Lame (born 1953), Nigerian educator and politician * Jennifer Lame (), American film editor * Quintín Lame (1880–1967), Colombian ...

, in listening tests that determine sound quality. In contrast,

CPython CPython is the reference implementation of the Python (programming language), Python programming language. Written in C (programming language), C and Python, CPython is the default and most widely used implementation of the Python language. CP ...

, the reference implementation of the

Python programming language Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically-typed and garbage-collected. It supports multiple programming p ...

, is also the implementation most widely used in production.

Testing

Testing An examination (exam or evaluation) or test is an educational assessment intended to measure a test-taker's knowledge, skill, aptitude, physical fitness, or classification in many other topics (e.g., beliefs). A test may be administered verba ...

the implementation-vs-specification relationship further enhances the

production Production may refer to: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (goods and services) * Production as a stati ...

's inter-process efficiencies:

References

{{Reflist Test items Software engineering terminology