Fix rekey, improve coverage

ChaChaPoly key is expected to be 256 bits long. It's safe to disregard the MAC portion.
2021-04-27 15:37:48 +01:00
parent 991d7390ea
commit ffde489e53
3 changed files with 20 additions and 0 deletions
@@ -56,6 +56,10 @@ hkdf(Hash, Key, Data) ->

 -spec rekey(Cipher :: enoise_cipher_state:noise_cipher(),
            Key :: binary()) -> binary() | {error, term()}.
+rekey('ChaChaPoly', K0) ->
+    KLen = enacl:aead_chacha20poly1305_ietf_KEYBYTES(),
+    <<K:KLen/binary, _/binary>> = encrypt('ChaChaPoly', K0, ?MAX_NONCE, <<>>, <<0:(32*8)>>),
+    K;
 rekey(Cipher, K) ->
    encrypt(Cipher, K, ?MAX_NONCE, <<>>, <<0:(32*8)>>).