diff --git a/staticlibs/Android.bp b/staticlibs/Android.bp
index bcbee07..ecff6c7 100644
--- a/staticlibs/Android.bp
+++ b/staticlibs/Android.bp
@@ -73,6 +73,7 @@
   host_supported: true,
   visibility: [
       "//frameworks/libs/net/common/tests:__subpackages__",
+      "//frameworks/libs/net/client-libs/tests:__subpackages__",
   ],
   static_libs: [
       "kotlin-test"
diff --git a/staticlibs/framework/com/android/net/module/util/NetworkIdentityUtils.java b/staticlibs/framework/com/android/net/module/util/NetworkIdentityUtils.java
new file mode 100644
index 0000000..94e6017
--- /dev/null
+++ b/staticlibs/framework/com/android/net/module/util/NetworkIdentityUtils.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.net.module.util;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+
+/**
+ * Utilities to examine {@link android.net.NetworkIdentity}.
+ */
+public class NetworkIdentityUtils {
+    /**
+     * Scrub given IMSI on production builds.
+     */
+    @NonNull
+    public static String scrubSubscriberId(@Nullable String subscriberId) {
+        if (subscriberId != null) {
+            // TODO: parse this as MCC+MNC instead of hard-coding
+            return subscriberId.substring(0, Math.min(6, subscriberId.length())) + "...";
+        } else {
+            return "null";
+        }
+    }
+
+    /**
+     * Scrub given IMSI on production builds.
+     */
+    @Nullable
+    public static String[] scrubSubscriberIds(@Nullable String[] subscriberIds) {
+        if (subscriberIds == null) return null;
+        final String[] res = new String[subscriberIds.length];
+        for (int i = 0; i < res.length; i++) {
+            res[i] = scrubSubscriberId(subscriberIds[i]);
+        }
+        return res;
+    }
+}
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/NetworkIdentityUtilsTest.kt b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkIdentityUtilsTest.kt
new file mode 100644
index 0000000..2904e12
--- /dev/null
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/NetworkIdentityUtilsTest.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.net.module.util
+
+import androidx.test.filters.SmallTest
+import androidx.test.runner.AndroidJUnit4
+import com.android.net.module.util.NetworkIdentityUtils.scrubSubscriberId
+import com.android.net.module.util.NetworkIdentityUtils.scrubSubscriberIds
+import com.android.testutils.assertContainsStringsExactly
+import org.junit.Test
+import org.junit.runner.RunWith
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+
+@RunWith(AndroidJUnit4::class)
+@SmallTest
+class NetworkIdentityUtilsTest {
+    @Test
+    fun testScrubSubscriberId() {
+        assertEquals("123456...", scrubSubscriberId("1234567890123"))
+        assertEquals("123456...", scrubSubscriberId("1234567"))
+        assertEquals("123...", scrubSubscriberId("123"))
+        assertEquals("...", scrubSubscriberId(""))
+        assertEquals("null", scrubSubscriberId(null))
+    }
+
+    @Test
+    fun testScrubSubscriberIds() {
+        assertContainsStringsExactly(scrubSubscriberIds(arrayOf("1234567", "", null))!!,
+                "123456...", "...", "null")
+        assertContainsStringsExactly(scrubSubscriberIds(arrayOf("12345"))!!, "12345...")
+        assertContainsStringsExactly(scrubSubscriberIds(arrayOf())!!)
+        assertNull(scrubSubscriberIds(null))
+    }
+}
\ No newline at end of file