2.2.2 FFC DH Parameters

This structure specifies field parameters for use in deriving finite field cryptography (FFC) Diffie-Hellman (DH) ([SP800-56A] section 5.7.1) keys, as specified in section 3.1.4.1.2.

0	1	2	3	4	5	6	7	8	9	1 0	1	2	3	4	5	6	7	8	9	2 0	1	2	3	4	5	6	7	8	9	3 0	1
Length
0x44								0x48								0x50								0x4D
Key length
Field order (variable)
...
...
Generator (variable)
...
...

Length (4 bytes):  A 32-bit unsigned integer. This field MUST be the length, in bytes, of the entire structure. This field is encoded using little-endian format.

Key length (4 bytes): A 32-bit unsigned integer. This field MUST be the length, in bytes, of the public key. This field is encoded using little-endian format.

Field order (variable): This is the large prime field order, and is a domain parameter for the FFC DH algorithm ([SP800-56A] section 5.7.1). This field parameter is referred to as p in [SP800-56A] section 3.2. It MUST be encoded in big-endian format. The length of this field, in bytes, MUST be equal to the value of the Key length field.

Generator (variable): The generator of the subgroup, a domain parameter for the FFC DH algorithm ([SP800-56A] section 5.7.1). This field parameter is referred to as g in [SP800-56A] section 3.2. It MUST be encoded in big-endian format. The length of this field, in bytes, MUST be equal to the value of the Key length field.