FEAT: support for direct DH params initialization from .key files

src/mezz/codec-ssh-key.reb

@@ -142,6 +142,17 @@ wrap [
 				]
 				"RSA PUBLIC KEY"  [ return init-rsa-public-key  data ]
 				"RSA PRIVATE KEY" [ return init-rsa-private-key data ]
+				"DH PARAMETERS" [
+					parse data [
+						'SEQUENCE into [
+							'INTEGER set p binary!
+							'INTEGER set g binary!
+						] (
+							return dh-init :g :p
+						)
+					]
+
+				]
 			]
 			none ; no success!
 		]

src/tests/units/crypt-test.r3

@@ -224,6 +224,13 @@ sY29ouezv4Xz2PuMch5VGPP+CDqzCM4loWgV
 --test-- "Init RSA key from file"
 	--assert handle? try [key: decode 'ssh-key read %units/files/rebol-public.ppk]
 	rsa key none ; release it, as it is not GCed yet.
+
+--test-- "Init public DH params from file"
+	--assert all [
+		handle? key: load %units/files/dhparam2048.key
+		'dhm = query/mode key 'type
+		dh/release key
+	]
 ===end-group===
 
 ===start-group=== "PPK codec"

src/tests/units/files/dhparam2048.key

@@ -0,0 +1,8 @@
+-----BEGIN DH PARAMETERS-----
+MIIBCAKCAQEAhR9gLa+RbIUY+u3qZHRwTfw4Q0VoJOv4FK3et9HQNSvZmmUqzcG/
+t3v3TPD3NRsLTh7hrvQcWFR7dsgqLFjqrMvthcRXsLYOxsT9ERL3nMPloEItggRG
+9hk3RzGFYb9nx56RXDJ3Nh+/pYfG3Ab+3gt+V/7Ato+Ws61lHVQmQ1cBUvkdjy4i
+uIm5vr91VVgMc8Bi9PvhsPhjU4f9LQIykiY7+nsJpbgNdlU55Db8/Atc3PnL11z/
+xXjmnj1QBjWymkz5LDEMJYCkMcFGwiToL6+jYjAkG1GpU6Jt4C5Z00E4LERy/jCi
+geGoH8yNQvldeqw5lTcNpaWWB2+ROqUj0wIBAg==
+-----END DH PARAMETERS-----