diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/auth/ExternalServiceCredentialGenerator.java b/service/src/main/java/org/whispersystems/textsecuregcm/auth/ExternalServiceCredentialGenerator.java
index 9e2e591be..f3fcdc428 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/auth/ExternalServiceCredentialGenerator.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/auth/ExternalServiceCredentialGenerator.java
@@ -30,16 +30,16 @@ public class ExternalServiceCredentialGenerator {
     this(key, new byte[0], false, prependUsername);
   }
 
-  public ExternalServiceCredentialGenerator(byte[] key, byte[] userIdKey, boolean usernameDerivation,
-      boolean prependUsername) {
-    this(key, userIdKey, usernameDerivation, prependUsername, Clock.systemUTC());
-  }
-
   @VisibleForTesting
   public ExternalServiceCredentialGenerator(byte[] key, byte[] userIdKey, boolean usernameDerivation) {
     this(key, userIdKey, usernameDerivation, true);
   }
 
+  private ExternalServiceCredentialGenerator(byte[] key, byte[] userIdKey, boolean usernameDerivation,
+      boolean prependUsername) {
+    this(key, userIdKey, usernameDerivation, prependUsername, Clock.systemUTC());
+  }
+
   @VisibleForTesting
   public ExternalServiceCredentialGenerator(byte[] key, byte[] userIdKey, boolean usernameDerivation,
       boolean prependUsername, Clock clock) {