NIST has updated two publications on cryptographic key-establishment schemes—procedures that result in secret keying material being shared among different parties. The first publication, Special Publication (SP) 800-56A Revision 3, Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography, approves the use of specific safe-prime groups of domain parameters for the finite field Diffie-Hellman (DH) and Menezes-Qu-Vanstone (MQV) key establishment schemes, in addition to the previously approved domain parameter sets.
The second publication, SP 800-56C Revision 1, Recommendation for Key-Derivation Methods in Key-Establishment Schemes, specifies two categories of key-derivation methods that can be used. The first category consists of a family of one-step key-derivation functions, which derive keying material from a shared secret generated during the execution of a key-establishment scheme. The second category consists of two-step key-derivation methods that involve the following two steps: 1) randomness extraction, to obtain a single cryptographic key-derivation key from a shared secret generated during the execution of a key-establishment scheme; and 2) key expansion, to derive keying material from that key-derivation key and other information.