rename random_seed, remove the hash

archethic-foundation · Jun 7, 2024 · 3353634 · 3353634
1 parent 4a3d5f6
commit 3353634
Show file tree

Hide file tree

Showing 2 changed files with 21 additions and 17 deletions.
diff --git a/lib/archethic/crypto.ex b/lib/archethic/crypto.ex
@@ -585,20 +585,24 @@ defmodule Archethic.Crypto do
       40, 0, 68, 224, 177, 110, 180, 24>>
       ```
   """
-  @spec ec_encrypt(message :: binary(), public_key :: key(), random_seed :: binary() | :undefined) ::
+  @spec ec_encrypt(
+          message :: binary(),
+          public_key :: key(),
+          ephemeral_entropy_priv_key :: binary() | nil
+        ) ::
           binary()
   def ec_encrypt(
         message,
         <<curve_id::8, _::8, public_key::binary>> = _public_key,
-        random_seed \\ :undefined
+        ephemeral_entropy_priv_key \\ nil
       )
       when is_binary(message) do
     start_time = System.monotonic_time()
 
     curve = ID.to_curve(curve_id)
 
     {ephemeral_public_key, ephemeral_private_key} =
-      generate_ephemeral_encryption_keys(curve, random_seed)
+      generate_ephemeral_encryption_keys(curve, ephemeral_entropy_priv_key)
 
     # Derivate secret using ECDH with the given public key and the ephemeral private key
     shared_key =
@@ -624,14 +628,14 @@ defmodule Archethic.Crypto do
     <<ephemeral_public_key::binary, tag::binary, cipher::binary>>
   end
 
-  defp generate_ephemeral_encryption_keys(:ed25519, random_seed),
-    do: generate_ephemeral_encryption_keys(:x25519, random_seed)
+  defp generate_ephemeral_encryption_keys(:ed25519, ephemeral_entropy_priv_key),
+    do: generate_ephemeral_encryption_keys(:x25519, ephemeral_entropy_priv_key)
 
-  defp generate_ephemeral_encryption_keys(curve, :undefined),
+  defp generate_ephemeral_encryption_keys(curve, nil),
     do: :crypto.generate_key(:ecdh, curve)
 
-  defp generate_ephemeral_encryption_keys(curve, random_seed),
-    do: :crypto.generate_key(:ecdh, curve, :crypto.hash(:sha256, random_seed))
+  defp generate_ephemeral_encryption_keys(curve, ephemeral_entropy_priv_key),
+    do: :crypto.generate_key(:ecdh, curve, ephemeral_entropy_priv_key)
 
   defp derivate_secrets(dh_key) do
     pseudorandom_key = :crypto.hash(:sha256, dh_key)

diff --git a/test/archethic/crypto_test.exs b/test/archethic/crypto_test.exs
@@ -15,13 +15,13 @@ defmodule CryptoTest do
   doctest Crypto
 
   test "giving a seed always result in the same result" do
-    random_seed = :crypto.strong_rand_bytes(32)
+    ephemeral_entropy_priv_key = :crypto.strong_rand_bytes(32)
     {pub, _} = Crypto.generate_deterministic_keypair("seed", :secp256r1)
 
     assert Crypto.ec_encrypt("msg", pub) != Crypto.ec_encrypt("msg", pub)
 
-    assert Crypto.ec_encrypt("msg", pub, random_seed) ==
-             Crypto.ec_encrypt("msg", pub, random_seed)
+    assert Crypto.ec_encrypt("msg", pub, ephemeral_entropy_priv_key) ==
+             Crypto.ec_encrypt("msg", pub, ephemeral_entropy_priv_key)
   end
 
   property "symmetric aes encryption and decryption" do
@@ -45,14 +45,14 @@ defmodule CryptoTest do
     end
   end
 
-  property "symmetric EC encryption and decryption with ECDSA (with fixed random_seed)" do
+  property "symmetric EC encryption and decryption with ECDSA (with fixed ephemeral_entropy_priv_key)" do
     check all(
             seed <- StreamData.binary(length: 32),
             data <- StreamData.binary(min_length: 1),
-            random_seed <- StreamData.binary(length: 32)
+            ephemeral_entropy_priv_key <- StreamData.binary(length: 32)
           ) do
       {pub, pv} = Crypto.generate_deterministic_keypair(seed, :secp256r1)
-      cipher = Crypto.ec_encrypt(data, pub, random_seed)
+      cipher = Crypto.ec_encrypt(data, pub, :crypto.hash(:sha256, ephemeral_entropy_priv_key))
       is_binary(cipher) and data == Crypto.ec_decrypt!(cipher, pv)
     end
   end
@@ -68,14 +68,14 @@ defmodule CryptoTest do
     end
   end
 
-  property "symmetric EC encryption and decryption with Ed25519 (with fixed random_seed)" do
+  property "symmetric EC encryption and decryption with Ed25519 (with fixed ephemeral_entropy_priv_key)" do
     check all(
             seed <- StreamData.binary(length: 32),
             data <- StreamData.binary(min_length: 1),
-            random_seed <- StreamData.binary(length: 32)
+            ephemeral_entropy_priv_key <- StreamData.binary(length: 32)
           ) do
       {pub, pv} = Crypto.generate_deterministic_keypair(seed, :ed25519)
-      cipher = Crypto.ec_encrypt(data, pub, random_seed)
+      cipher = Crypto.ec_encrypt(data, pub, :crypto.hash(:sha256, ephemeral_entropy_priv_key))
       is_binary(cipher) and data == Crypto.ec_decrypt!(cipher, pv)
     end
   end