Ocamlnet 4 Reference Manual : Netx509_pubkey.Keyagreement

`sig
val dh : Netx509_pubkey.kex_alg
val ec : Netx509_pubkey.kex_alg
val ecdh : Netx509_pubkey.kex_alg
val ecmqv : Netx509_pubkey.kex_alg
val kea : Netx509_pubkey.kex_alg
val catalog :
(string * string list * Netx509_pubkey.kex_alg * Netx509_pubkey.oid) list
val alg_id_of_kex_alg : Netx509_pubkey.kex_alg -> Netx509_pubkey.alg_id
val key_oid_of_kex_alg : Netx509_pubkey.kex_alg -> Netx509_pubkey.oid
end`