diff --git a/exercises/practice/affine-cipher/.meta/example.ex b/exercises/practice/affine-cipher/.meta/example.ex
index b857c193cb..53c0c9c302 100644
--- a/exercises/practice/affine-cipher/.meta/example.ex
+++ b/exercises/practice/affine-cipher/.meta/example.ex
@@ -34,7 +34,7 @@ defmodule AffineCipher do
   @doc """
   Decode an encrypted message using a key
   """
-  @spec decode(key :: key(), message :: String.t()) :: {:ok, String.t()} | {:error, String.t()}
+  @spec decode(key :: key(), encrypted :: String.t()) :: {:ok, String.t()} | {:error, String.t()}
   def decode(%{a: a, b: b}, encrypted) do
     if Integer.gcd(a, @alphabet_size) != 1 do
       {:error, "a and m must be coprime."}
diff --git a/exercises/practice/affine-cipher/lib/affine_cipher.ex b/exercises/practice/affine-cipher/lib/affine_cipher.ex
index f04dc5cc1e..1fab119051 100644
--- a/exercises/practice/affine-cipher/lib/affine_cipher.ex
+++ b/exercises/practice/affine-cipher/lib/affine_cipher.ex
@@ -14,7 +14,7 @@ defmodule AffineCipher do
   @doc """
   Decode an encrypted message using a key
   """
-  @spec decode(key :: key(), message :: String.t()) :: {:ok, String.t()} | {:error, String.t()}
+  @spec decode(key :: key(), encrypted :: String.t()) :: {:ok, String.t()} | {:error, String.t()}
   def decode(%{a: a, b: b}, encrypted) do
   end
 end