The innermost layer cipher_state

2018-03-01 11:44:23 +01:00
parent cb626ab07c
commit d78c774b55
3 changed files with 151 additions and 0 deletions
@@ -0,0 +1,54 @@
+%%%-------------------------------------------------------------------
+%%% @copyright (C) 2018, Aeternity Anstalt
+%%%-------------------------------------------------------------------
+
+-module(enoise_crypto).
+
+-include("enoise.hrl").
+
+-export([decrypt/5, encrypt/5, rekey/2, hash/2, pad/3, hashlen/1, dhlen/1, new_key_pair/1, hkdf/3, dh/3]).
+
+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)) }.
+
+dh(dh25519, KeyPair, PubKey) ->
+    enacl:curve25519_scalarmult(KeyPair#key_pair.pik, PubKey).
+
+hkdf(_, _, _) -> [].
+
+rekey(Cipher, K) ->
+    encrypt(Cipher, K, ?MAX_NONCE, <<>>, <<0:(32*8)>>).
+
+encrypt('ChaChaPoly', K, N, Ad, PlainText) ->
+    enacl:aead_chacha20poly1305_encrypt(K, N, Ad, PlainText).
+
+-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).
+
+hash(blake2b, Data) ->
+    enacl:generichash(64, Data);
+hash(blake2s, Data) ->
+    enacl:generichash(32, Data).
+
+pad(Data, MinSize, PadByte) ->
+    case byte_size(Data) of
+        N when N >= MinSize ->
+            Data;
+        N ->
+            PadData = << <<PadByte:8>> || _ <- lists:seq(1, MinSize - N) >>,
+            <<Data/binary, PadData/binary>>
+    end.
+
+hashlen(sha256)  -> 32;
+hashlen(sha512)  -> 64;
+hashlen(blake2s) -> 32;
+hashlen(blake2b) -> 64.
+
+dhlen(dh25519) -> 32;
+dhlen(dh448)   -> 56.