diff --git a/aws-android-sdk-cognitoauth/src/main/java/com/amazonaws/mobileconnectors/cognitoauth/util/Pkce.java b/aws-android-sdk-cognitoauth/src/main/java/com/amazonaws/mobileconnectors/cognitoauth/util/Pkce.java
index 6cd7fe44188..3dd8dcd0ca8 100644
--- a/aws-android-sdk-cognitoauth/src/main/java/com/amazonaws/mobileconnectors/cognitoauth/util/Pkce.java
+++ b/aws-android-sdk-cognitoauth/src/main/java/com/amazonaws/mobileconnectors/cognitoauth/util/Pkce.java
@@ -25,8 +25,8 @@
 
 /**
  * Utility class to generate random string, hash, and encoding.
+ *
  */
-
 public final class Pkce {
 
     /**
@@ -69,6 +69,6 @@ public final static String encodeBase64(String str) {
             return null;
         }
         byte[] data = str.getBytes(Charset.forName("ISO-8859-1"));
-        return Base64.encodeToString(data, Base64.NO_PADDING);
+        return Base64.encodeToString(data, Base64.URL_SAFE | Base64.NO_WRAP | Base64.NO_PADDING);
     }
 }