Interface ISp80056CKdf

SP 800-56C key derivation as an injectable service. Mirrors Sp80056C; inject it, or construct Sp80056CKdf directly.

public interface ISp80056CKdf

Methods

The extraction step (§5.1): K_DK = MAC(salt, Z). Expand the result with Sp800108 using ExpansionPrf.

byte[] Extract(ReadOnlySpan<byte> sharedSecret, Extraction extraction, SecurityStrength strength)

sharedSecret ReadOnlySpan<byte>: Z.
extraction Extraction: HMAC or AES-CMAC extraction and its salt.
strength SecurityStrength: The target security strength, at least 112 bits.

One-step key derivation (§4): K(i) = H(counter || Z || FixedInfo).

byte[] OneStep(ReadOnlySpan<byte> sharedSecret, OneStepFunction function, ReadOnlySpan<byte> fixedInfo, BitLength length, SecurityStrength strength)

sharedSecret ReadOnlySpan<byte>: Z.
function OneStepFunction: The auxiliary function H.
fixedInfo ReadOnlySpan<byte>: FixedInfo, for example AlgorithmID || PartyUInfo || PartyVInfo.
length BitLength: The output length L.
strength SecurityStrength: The target security strength, at least 112 bits.

Two-step key derivation (§5): extracts a key-derivation key from Z, then expands it with SP 800-108 using the PRF the extraction requires. To derive several keys from one Z, call Extract(ReadOnlySpan<byte>, Extraction, SecurityStrength) once and Derive(ReadOnlySpan<byte>, Prf, KeyExpansion, BitLength) once per key with distinct fixed input.

byte[] TwoStep(ReadOnlySpan<byte> sharedSecret, Extraction extraction, KeyExpansion expansion, BitLength length, SecurityStrength strength)