Examples are the first CERN's httpd,[1] Serpent cipher, base64 variants,[2] and SHA-3.
[3] The Openwall Project maintains a list of several algorithms with their reference source code in the public domain.
For example, the Fraunhofer reference implementation of the MP3 standard usually does not compare favorably to other common implementations, such as LAME, in listening tests that determine sound quality.
Testing the implementation-vs-specification relationship further enhances the production's inter-process efficiencies: A reference implementation is, in general, an implementation of a specification to be used as a definitive interpretation for that specification.
During the development of the ... conformance test suite, at least one relatively trusted implementation of each interface is necessary to (1) discover errors or ambiguities in the specification, and (2) validate the correct functioning of the test suite.