diff --git a/lib/lti_result.ex b/lib/lti_result.ex
index 5274c36..f1478ff 100644
--- a/lib/lti_result.ex
+++ b/lib/lti_result.ex
@@ -27,24 +27,26 @@ defmodule LTIResult do
       {:ok, "iyyQNRQyXTlpLJPJns3ireWjQxo%3D"}
   """
   def signature(url, oauth_header, secret) do
-    {parameters, [{"oauth_signature", received_signature}]} =
-      extract_header_elements(oauth_header)
-
-    with {:ok, _} <- validate_parameters(parameters) do
-      basestring = base_string(url, parameters)
-
-      signature = generate_signature(secret, basestring)
-
-      if signature == received_signature do
-        {:ok, signature}
-      else
-        {:error, [:unmatching_signatures]}
+    with {parameters, [{"oauth_signature", received_signature}]} <-
+           extract_header_elements(oauth_header),
+         {:ok, _} <- validate_parameters(parameters),
+         {_, signature_method} <-
+           List.keyfind(parameters, "oauth_signature_method", 0),
+         basestring <- base_string(url, parameters),
+         signature <- generate_signature(secret, signature_method, basestring) do
+      case signature == received_signature do
+        true ->
+          {:ok, signature}
+
+        false ->
+          {:error, [:unmatching_signatures]}
       end
     end
   end
 
-  defp generate_signature(secret, basestring) do
-    :sha
+  defp generate_signature(secret, signature_method, basestring) do
+    signature_method
+    |> get_signature_method()
     |> :crypto.hmac(
       percent_encode(secret) <> "&",
       basestring
@@ -52,6 +54,9 @@ defmodule LTIResult do
     |> Base.encode64()
   end
 
+  defp get_signature_method("HMAC-SHA256"), do: :sha256
+  defp get_signature_method(_), do: :sha
+
   defp extract_header_elements(header) do
     header
     |> String.trim_leading("OAuth ")
diff --git a/test/lti_result_test.exs b/test/lti_result_test.exs
index 77f1cbf..5d54a04 100644
--- a/test/lti_result_test.exs
+++ b/test/lti_result_test.exs
@@ -2,175 +2,219 @@ defmodule LTIResultTest do
   use ExUnit.Case
   doctest LTIResult, only: [signature: 4]
 
-  test "returns {:ok, determined_signature} if the signature is correct" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:ok, "iyyQNRQyXTlpLJPJns3ireWjQxo="}
+  describe "signature_method SHMAC-SHA1" do
+    test "returns {:ok, determined_signature} if the signature is correct" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:ok, "iyyQNRQyXTlpLJPJns3ireWjQxo="}
+    end
+
+    test "returns identical signatures for downcase url and url with capitals" do
+      return1 =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      return2 =
+        LTIResult.signature(
+          "https://ExamPle.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return1 == return2
+    end
+
+    test "returns {:ok, determined_signature} if a bodyhash is included" do
+      return =
+        LTIResult.signature(
+          "http://474c3d0e.ngrok.io/capp11/api/v1/lti_results",
+          "OAuth oauth_version=\"1.0\",oauth_nonce=\"tjtwip19l78355dl\",oauth_timestamp=\"1528808890\",oauth_consumer_key=\"Defacto\",oauth_body_hash=\"qvrl3dbLTUqxHeCDqof%2Ffz%2Bygc0%3D\",oauth_signature_method=\"HMAC-SHA1\",oauth_signature=\"WF9NUX6QCgKXNb2nNYEZ4evBmSk%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:ok, "WF9NUX6QCgKXNb2nNYEZ4evBmSk="}
+    end
+
+    test "returns an error if the signature is incorrect due to difference in key" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key12345\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:unmatching_signatures]}
+    end
+
+    test "returns an error if the signature is incorrect due to difference in method" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA2\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:unmatching_signatures]}
+    end
+
+    test "returns an error if the signature is incorrect due to difference in timestamp" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"152500000\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:unmatching_signatures]}
+    end
+
+    test "returns an error if the signature is incorrect due to difference in nonce" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"32123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:unmatching_signatures]}
+    end
+
+    test "returns an error if version is incorrect" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"2.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:incorrect_version]}
+    end
+
+    test "returns an error if duplicated parameters are present" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:duplicated_parameters]}
+    end
+
+    test "returns an error if the consumer key is missing" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:missing_required_parameters]}
+    end
+
+    test "returns an error if the signature method is missing" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:missing_required_parameters]}
+    end
+
+    test "returns an error if the timestamp is missing" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:missing_required_parameters]}
+    end
+
+    test "returns an error if oauth version is missing" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:incorrect_version, :missing_required_parameters]}
+    end
+
+    test "returns an error if nonce is missing" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:missing_required_parameters]}
+    end
+
+    test "returns an error if an unsupported parameter is provided" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth unsupported_derpvalue=\"123\",oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:error, [:unsupported_parameters]}
+    end
   end
 
-  test "returns identical signatures for downcase url and url with capitals" do
-    return1 =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    return2 =
-      LTIResult.signature(
-        "https://ExamPle.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return1 == return2
-  end
-
-  test "returns {:ok, determined_signature} if a bodyhash is included" do
-    return =
-      LTIResult.signature(
-        "http://474c3d0e.ngrok.io/capp11/api/v1/lti_results",
-        "OAuth oauth_version=\"1.0\",oauth_nonce=\"tjtwip19l78355dl\",oauth_timestamp=\"1528808890\",oauth_consumer_key=\"Defacto\",oauth_body_hash=\"qvrl3dbLTUqxHeCDqof%2Ffz%2Bygc0%3D\",oauth_signature_method=\"HMAC-SHA1\",oauth_signature=\"WF9NUX6QCgKXNb2nNYEZ4evBmSk%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:ok, "WF9NUX6QCgKXNb2nNYEZ4evBmSk="}
-  end
-
-  test "returns an error if the signature is incorrect due to difference in key" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key12345\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:unmatching_signatures]}
-  end
-
-  test "returns an error if the signature is incorrect due to difference in method" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA2\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:unmatching_signatures]}
-  end
-
-  test "returns an error if the signature is incorrect due to difference in timestamp" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"152500000\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:unmatching_signatures]}
-  end
-
-  test "returns an error if the signature is incorrect due to difference in nonce" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"32123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:unmatching_signatures]}
-  end
-
-  test "returns an error if version is incorrect" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"2.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:incorrect_version]}
-  end
-
-  test "returns an error if duplicated parameters are present" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:duplicated_parameters]}
-  end
-
-  test "returns an error if the consumer key is missing" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:missing_required_parameters]}
-  end
-
-  test "returns an error if the signature method is missing" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:missing_required_parameters]}
-  end
-
-  test "returns an error if the timestamp is missing" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:missing_required_parameters]}
-  end
-
-  test "returns an error if oauth version is missing" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:incorrect_version, :missing_required_parameters]}
-  end
-
-  test "returns an error if nonce is missing" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:missing_required_parameters]}
-  end
-
-  test "returns an error if an unsupported parameter is provided" do
-    return =
-      LTIResult.signature(
-        "https://example.com",
-        "OAuth unsupported_derpvalue=\"123\",oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA1\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
-        "random_secret"
-      )
-
-    assert return == {:error, [:unsupported_parameters]}
+  describe "signature_method SHMAC-SHA256" do
+    test "returns {:ok, determined_signature} if the signature is correct" do
+      return =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA256\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"wLwhR7dk5e4dVsvlhjK+fyWKSGzKw+v+tO96twgaHI8%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:ok, "wLwhR7dk5e4dVsvlhjK+fyWKSGzKw+v+tO96twgaHI8="}
+    end
+
+    test "returns identical signatures for downcase url and url with capitals" do
+      return1 =
+        LTIResult.signature(
+          "https://example.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA256\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      return2 =
+        LTIResult.signature(
+          "https://ExamPle.com",
+          "OAuth oauth_consumer_key=\"key1234\",oauth_signature_method=\"HMAC-SHA256\",oauth_timestamp=\"1525076552\",oauth_nonce=\"123\",oauth_version=\"1.0\",oauth_signature=\"iyyQNRQyXTlpLJPJns3ireWjQxo%3D\"",
+          "random_secret"
+        )
+
+      assert return1 == return2
+    end
+
+    test "returns {:ok, determined_signature} if a bodyhash is included" do
+      return =
+        LTIResult.signature(
+          "http://474c3d0e.ngrok.io/capp11/api/v1/lti_results",
+          "OAuth oauth_version=\"1.0\",oauth_nonce=\"tjtwip19l78355dl\",oauth_timestamp=\"1528808890\",oauth_consumer_key=\"Defacto\",oauth_body_hash=\"qvrl3dbLTUqxHeCDqof%2Ffz%2Bygc0%3D\",oauth_signature_method=\"HMAC-SHA256\",oauth_signature=\"aols3rXaIgpdQ9Ux4jQtbSl9E/AX+kvl7xp6BPzzzmk%3D\"",
+          "random_secret"
+        )
+
+      assert return == {:ok, "aols3rXaIgpdQ9Ux4jQtbSl9E/AX+kvl7xp6BPzzzmk="}
+    end
   end
 end