Bit Position,Description,Semantics Definition,Reference
0,Unauthenticated,Section 3.1,[RFC4656]
1,Authenticated,Section 3.1,[RFC4656]
2,Encrypted,Section 3.1,[RFC4656]
3,Reserved,Section 3.2.4,[RFC7718]
4,IKEv2-derived Shared Secret Key,"Section 3.2.4 of [RFC7718], Section 5 of [RFC7717]",[RFC7718][RFC7717]
5-31,Unassigned,,