diff --git a/lib/mix/tasks/guardian.gen.secret.ex b/lib/mix/tasks/guardian.gen.secret.ex
index 223bce8d3..9035078f8 100644
--- a/lib/mix/tasks/guardian.gen.secret.ex
+++ b/lib/mix/tasks/guardian.gen.secret.ex
@@ -27,7 +27,7 @@ defmodule Mix.Tasks.Guardian.Gen.Secret do
   end
 
   defp random_string(length) when length > 31 do
-    length |> :crypto.strong_rand_bytes() |> Base.encode64() |> binary_part(0, length)
+    length |> :crypto.strong_rand_bytes() |> Base.url_encode64() |> binary_part(0, length)
   end
 
   defp random_string(_), do: Mix.raise("The secret should be at least 32 characters long")