diff --git a/lib/aws_auth/utils.ex b/lib/aws_auth/utils.ex
index bd188ce..0e3acee 100644
--- a/lib/aws_auth/utils.ex
+++ b/lib/aws_auth/utils.ex
@@ -49,7 +49,11 @@ defmodule AWSAuth.Utils do
   end
 
   def hmac_sha256(key, data) do
-    :crypto.hmac(:sha256, key, data)
+    if Code.ensure_loaded?(:crypto) and function_exported?(:crypto, :mac, 4) do
+      :crypto.mac(:hmac, :sha256, key, data)
+    else
+      :crypto.hmac(:sha256, key, data)
+    end
   end
 
   def bytes_to_string(bytes) do
diff --git a/mix.exs b/mix.exs
index 68628e0..e4918b9 100644
--- a/mix.exs
+++ b/mix.exs
@@ -14,7 +14,7 @@ defmodule AWSAuth.Mixfile do
   end
 
   def application do
-    [applications: [:logger]]
+    [applications: [:logger, :crypto]]
   end
 
   defp deps do