diff --git a/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java b/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
index 111ffd29228c8..5fdfe1983f0aa 100644
--- a/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
+++ b/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
@@ -272,9 +272,8 @@ public class SyntheticPasswordManager {
          * AuthenticationToken.mSyntheticPassword for details on what each block means.
          */
         private void recreate(byte[] escrowSplit0, byte[] escrowSplit1) {
-            mSyntheticPassword = String.valueOf(HexEncoding.encode(
-                    SyntheticPasswordCrypto.personalisedHash(
-                            PERSONALIZATION_SP_SPLIT, escrowSplit0, escrowSplit1))).getBytes();
+            mSyntheticPassword = bytesToHex(SyntheticPasswordCrypto.personalisedHash(
+                    PERSONALIZATION_SP_SPLIT, escrowSplit0, escrowSplit1));
         }
 
         /**
@@ -1415,18 +1414,9 @@ public class SyntheticPasswordManager {
         return result;
     }
 
-    protected static final byte[] HEX_ARRAY = "0123456789ABCDEF".getBytes();
-    private static byte[] bytesToHex(byte[] bytes) {
-        if (bytes == null) {
-            return "null".getBytes();
-        }
-        byte[] hexBytes = new byte[bytes.length * 2];
-        for ( int j = 0; j < bytes.length; j++ ) {
-            int v = bytes[j] & 0xFF;
-            hexBytes[j * 2] = HEX_ARRAY[v >>> 4];
-            hexBytes[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
-        }
-        return hexBytes;
+    @VisibleForTesting
+    static byte[] bytesToHex(byte[] bytes) {
+        return HexEncoding.encodeToString(bytes).getBytes();
     }
 
     /**
diff --git a/services/tests/servicestests/src/com/android/server/locksettings/SyntheticPasswordTests.java b/services/tests/servicestests/src/com/android/server/locksettings/SyntheticPasswordTests.java
index c0a38b8749143..b5eea70f57a40 100644
--- a/services/tests/servicestests/src/com/android/server/locksettings/SyntheticPasswordTests.java
+++ b/services/tests/servicestests/src/com/android/server/locksettings/SyntheticPasswordTests.java
@@ -567,6 +567,13 @@ public class SyntheticPasswordTests extends BaseLockSettingsServiceTests {
         }
     }
 
+    @Test
+    public void testHexEncodingIsUppercase() {
+        final byte[] raw = new byte[] { (byte)0xAB, (byte)0xCD, (byte)0xEF };
+        final byte[] expected = new byte[] { 'A', 'B', 'C', 'D', 'E', 'F' };
+        assertArrayEquals(expected, SyntheticPasswordManager.bytesToHex(raw));
+    }
+
     // b/62213311
     //TODO: add non-migration work profile case, and unify/un-unify transition.
     //TODO: test token after user resets password