Public-Key Cryptography Standards
(PKCS) A set of standards for public-key cryptography, developed by RSA Data Security, Inc. in cooperation with an informal consortium, originally including Apple, Microsoft, DEC, Lotus, Sun and MIT. The PKCS have been cited by the OSI Implementers' Workshop (OIW) as a method for implementation of OSI standards.
PKCS includes both algorithm-specific and algorithm-independent implementation standards. Many algorithms are supported, including RSA and Diffie-Hellman key exchange, however, only the latter two are specifically detailed. PKCS also defines an algorithm-independent syntax for digital signatures, digital envelopes, and extended digital certificates; this enables someone implementing any cryptographic algorithm whatsoever to conform to a standard syntax, and thus achieve interoperability.