Recent advances in cryptography have made it desirable to use longer
cryptographic keys, and to make more careful use of these keys. In
particular, it is considered unwise by some cryptographers to use the
same key for multiple purposes. Since most cryptographic-based
systems perform a range of functions, such as authentication, key
exchange, integrity, and encryption, it is desirable to use different
cryptographic keys for these purposes.
This RFC does not define a particular protocol, but defines a set of
cryptographic transformations for use with arbitrary network
protocols and block cryptographic algorithm.