[Superseded by NIST SP 800-135 Rev. 1, "Recommendation for Existing Application-Specific Key Derivation Functions" (December 2011), http://www.nist.gov/manuscript-publication-search.cfm?pub_id=910283
] Cryptographic keys are vital to the security of internet security applications and protocols. Many widely-used internet security protocols have their own application-specific Key Derivation Functions (KDFs) that are used to generate the cryptographic keys required for their cryptographic functions. This Recommendation provides security requirements for those KDFs.