KATs on Prerequisite Algorithms. KATs shall be performed on all underlying prerequisite algorithms used in a given SP 800-56A scheme. Depending on which SP 800-56A scheme, this may include DSA, ECDSA, SHS, and/or RNG/DRBG. If these KATs are already performed as required by their underlying prerequisite algorithms, they should not need to be repeated for SP 800-56A if the same implementation is used.