Refactored + added some test vector support

src/enoise_crypto.erl

@@ -6,23 +6,50 @@
 
 -include("enoise.hrl").
 
--export([decrypt/5, encrypt/5, rekey/2, hash/2, pad/3, hashlen/1, dhlen/1, new_key_pair/1, hmac/3, hkdf/3, dh/3]).
+-export([ decrypt/5
+        , dh/3
+        , dhlen/1
+        , encrypt/5
+        , hash/2
+        , hashlen/1
+        , hkdf/3
+        , hmac/3
+        , new_key_pair/1
+        , pad/3
+        , pub_key/1
+        , rekey/2
+        ]).
 
+-record(key_pair, { puk, pik }).
+
+-opaque key_pair() :: #key_pair{}.
+
+-export_type([key_pair/0]).
+
+-define(MAC_LEN, 16).
+
+-spec new_key_pair(Algo :: enoise_hs_state:noise_dh()) -> key_pair().
 new_key_pair(dh25519) ->
     KeyPair = enacl:crypto_sign_ed25519_keypair(),
     #key_pair{ puk = enacl:crypto_sign_ed25519_public_to_curve25519(maps:get(public, KeyPair))
              , pik = enacl:crypto_sign_ed25519_secret_to_curve25519(maps:get(secret, KeyPair)) }.
 
+-spec dh(Algo :: enoise_hs_state:noise_dh(),
+         PrivKey :: key_pair(), PubKey :: binary()) -> binary().
 dh(dh25519, KeyPair, PubKey) ->
     enacl:curve25519_scalarmult(KeyPair#key_pair.pik, PubKey).
 
+-spec hmac(Hash :: enoise_sym_state:noise_hash(),
+           Key :: binary(), Data :: binary()) -> binary().
 hmac(Hash, Key, Data) ->
-    BLen = blocklen(blake2b),
+    BLen = blocklen(Hash),
     Block1 = hmac_format_key(Hash, Key, 16#36, BLen),
     Hash1 = hash(Hash, <<Block1/binary, Data/binary>>),
     Block2 = hmac_format_key(Hash, Key, 16#5C, BLen),
     hash(Hash, <<Block2/binary, Hash1/binary>>).
 
+-spec hkdf(Hash :: enoise_sym_state:noise_hash(),
+           Key :: binary(), Data :: binary()) -> [binary()].
 hkdf(Hash, Key, Data) ->
     TempKey = hmac(Hash, Key, Data),
     Output1 = hmac(Hash, TempKey, <<1:8>>),
@@ -30,24 +57,47 @@ hkdf(Hash, Key, Data) ->
     Output3 = hmac(Hash, TempKey, <<Output2/binary, 3:8>>),
     [Output1, Output2, Output3].
 
+-spec rekey(Cipher :: enoise_cipher_state:noise_cipher(),
+            Key :: binary()) -> binary().
 rekey(Cipher, K) ->
     encrypt(Cipher, K, ?MAX_NONCE, <<>>, <<0:(32*8)>>).
 
+-spec encrypt(Cipher :: enoise_cipher_state:noise_cipher(),
+              Key :: binary(), Nonce :: non_neg_integer(),
+              Ad :: binary(), PlainText :: binary()) ->
+                binary() | {error, term()}.
 encrypt('ChaChaPoly', K, N, Ad, PlainText) ->
-    enacl:aead_chacha20poly1305_encrypt(K, N, Ad, PlainText).
+    enacl:aead_chacha20poly1305_encrypt(K, N, Ad, PlainText);
+encrypt('AESGCM', K, N, Ad, PlainText) ->
+    Nonce = <<0:32, N:64>>,
+    {CipherText, CipherTag} = crypto:block_encrypt(aes_gcm, K, Nonce, {Ad, PlainText}),
+    <<CipherText/binary, CipherTag/binary>>.
 
 -spec decrypt(Cipher ::enoise_cipher_state:noise_cipher(),
               Key :: binary(), Nonce :: non_neg_integer(),
               AD :: binary(), CipherText :: binary()) ->
                 binary() | {error, term()}.
 decrypt('ChaChaPoly', K, N, Ad, CipherText) ->
-    enacl:aead_chacha20poly1305_decrypt(K, N, Ad, CipherText).
+    enacl:aead_chacha20poly1305_decrypt(K, N, Ad, CipherText);
+decrypt('AESGCM', K, N, Ad, CipherText0) ->
+    CTLen = byte_size(CipherText0) - ?MAC_LEN,
+    <<CipherText:CTLen/binary, MAC:?MAC_LEN/binary>> = CipherText0,
+    Nonce = <<0:32, N:64>>,
+    crypto:block_decrypt(aes_gcm, K, Nonce, {Ad, CipherText, MAC}).
 
+
+-spec hash(Hash :: enoise_sym_state:noise_hash(), Data :: binary()) -> binary().
 hash(blake2b, Data) ->
     {ok, Hash} = enacl:generichash(64, Data), Hash;
+hash(sha256, Data) ->
+    crypto:hash(sha256, Data);
+hash(sha512, Data) ->
+    crypto:hash(sha512, Data);
 hash(Hash, _Data) ->
     error({hash_not_implemented_yet, Hash}).
 
+-spec pad(Data :: binary(), MinSize :: non_neg_integer(),
+          PadByte :: integer()) -> binary().
 pad(Data, MinSize, PadByte) ->
     case byte_size(Data) of
         N when N >= MinSize ->
@@ -57,16 +107,22 @@ pad(Data, MinSize, PadByte) ->
             <<Data/binary, PadData/binary>>
     end.
 
+-spec pub_key(KeyPair :: key_pair()) -> binary().
+pub_key(#key_pair{ puk = PubKey }) -> PubKey.
+
+-spec hashlen(Hash :: enoise_sym_state:noise_hash()) -> non_neg_integer().
 hashlen(sha256)  -> 32;
 hashlen(sha512)  -> 64;
 hashlen(blake2s) -> 32;
 hashlen(blake2b) -> 64.
 
+-spec blocklen(Hash :: enoise_sym_state:noise_hash()) -> non_neg_integer().
 blocklen(sha256)  -> 64;
 blocklen(sha512)  -> 128;
 blocklen(blake2s) -> 64;
 blocklen(blake2b) -> 128.
 
+-spec dhlen(DH :: enoise_hs_state:noise_dh()) -> non_neg_integer().
 dhlen(dh25519) -> 32;
 dhlen(dh448)   -> 56.