diff --git a/common/FlaggedApi.bp b/common/FlaggedApi.bp
index d5cfde3..fef9ac3 100644
--- a/common/FlaggedApi.bp
+++ b/common/FlaggedApi.bp
@@ -47,3 +47,20 @@
     srcs: ["nearby_flags.aconfig"],
     visibility: ["//packages/modules/Connectivity:__subpackages__"],
 }
+
+aconfig_declarations {
+    name: "com.android.networksecurity.flags-aconfig",
+    package: "com.android.net.ct.flags",
+    container: "com.android.tethering",
+    srcs: ["networksecurity_flags.aconfig"],
+    visibility: ["//packages/modules/Connectivity:__subpackages__"],
+}
+
+java_aconfig_library {
+    name: "networksecurity_flags_java_lib",
+    aconfig_declarations: "com.android.networksecurity.flags-aconfig",
+    min_sdk_version: "30",
+    defaults: ["framework-minus-apex-aconfig-java-defaults"],
+    apex_available: ["com.android.tethering"],
+    visibility: ["//packages/modules/Connectivity:__subpackages__"],
+}
diff --git a/common/networksecurity_flags.aconfig b/common/networksecurity_flags.aconfig
new file mode 100644
index 0000000..ef8ffcd
--- /dev/null
+++ b/common/networksecurity_flags.aconfig
@@ -0,0 +1,9 @@
+package: "com.android.net.ct.flags"
+container: "com.android.tethering"
+flag {
+    name: "certificate_transparency_service"
+    is_exported: true
+    namespace: "network_security"
+    description: "Enable service for certificate transparency log list data"
+    bug: "319829948"
+}
diff --git a/framework/Android.bp b/framework/Android.bp
index deea6b6..4c4f792 100644
--- a/framework/Android.bp
+++ b/framework/Android.bp
@@ -63,6 +63,7 @@
         ":framework-connectivity-sources",
         ":net-utils-framework-common-srcs",
         ":framework-connectivity-api-shared-srcs",
+        ":framework-networksecurity-sources",
     ],
     aidl: {
         generate_get_transaction_name: true,
@@ -93,6 +94,7 @@
         "modules-utils-backgroundthread",
         "modules-utils-build",
         "modules-utils-preconditions",
+        "networksecurity_flags_java_lib",
         "framework-connectivity-javastream-protos",
     ],
     impl_only_static_libs: [
@@ -207,6 +209,7 @@
     },
     aconfig_declarations: [
         "com.android.net.flags-aconfig",
+        "com.android.networksecurity.flags-aconfig",
     ],
 }
 
@@ -307,6 +310,7 @@
     srcs: [
         ":framework-connectivity-sources",
         ":framework-connectivity-tiramisu-updatable-sources",
+        ":framework-networksecurity-sources",
         ":framework-nearby-java-sources",
         ":framework-thread-sources",
     ],
diff --git a/networksecurity/OWNERS b/networksecurity/OWNERS
new file mode 100644
index 0000000..1a4130a
--- /dev/null
+++ b/networksecurity/OWNERS
@@ -0,0 +1,4 @@
+# Bug component: 1479456
+
+sandrom@google.com
+tweek@google.com
diff --git a/networksecurity/framework/Android.bp b/networksecurity/framework/Android.bp
new file mode 100644
index 0000000..2b77926
--- /dev/null
+++ b/networksecurity/framework/Android.bp
@@ -0,0 +1,31 @@
+//
+// Copyright (C) 2024 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 {
+    default_team: "trendy_team_platform_security",
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+filegroup {
+    name: "framework-networksecurity-sources",
+    srcs: [
+        "src/**/*.java",
+        "src/**/*.aidl",
+    ],
+    path: "src",
+    visibility: [
+        "//packages/modules/Connectivity:__subpackages__",
+    ],
+}
diff --git a/networksecurity/framework/src/android/net/ct/CertificateTransparencyManager.java b/networksecurity/framework/src/android/net/ct/CertificateTransparencyManager.java
new file mode 100644
index 0000000..94521ae
--- /dev/null
+++ b/networksecurity/framework/src/android/net/ct/CertificateTransparencyManager.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024 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 android.net.ct;
+
+import android.annotation.FlaggedApi;
+import android.annotation.SystemService;
+
+import com.android.net.ct.flags.Flags;
+
+/**
+ * Provides the primary API for the Certificate Transparency Manager.
+ *
+ * @hide
+ */
+@FlaggedApi(Flags.FLAG_CERTIFICATE_TRANSPARENCY_SERVICE)
+@SystemService(CertificateTransparencyManager.SERVICE_NAME)
+public final class CertificateTransparencyManager {
+
+    public static final String SERVICE_NAME = "certificate_transparency";
+
+    /**
+     * Creates a new CertificateTransparencyManager instance.
+     *
+     * @hide
+     */
+    public CertificateTransparencyManager() {}
+}
diff --git a/networksecurity/framework/src/android/net/ct/ICertificateTransparencyManager.aidl b/networksecurity/framework/src/android/net/ct/ICertificateTransparencyManager.aidl
new file mode 100644
index 0000000..b5bce7f
--- /dev/null
+++ b/networksecurity/framework/src/android/net/ct/ICertificateTransparencyManager.aidl
@@ -0,0 +1,22 @@
+/**
+ * Copyright (c) 2024, 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 android.net.ct;
+
+/**
+* Interface for communicating with CertificateTransparencyService.
+* @hide
+*/
+interface ICertificateTransparencyManager {}
diff --git a/networksecurity/service/Android.bp b/networksecurity/service/Android.bp
new file mode 100644
index 0000000..66d201a
--- /dev/null
+++ b/networksecurity/service/Android.bp
@@ -0,0 +1,40 @@
+// Copyright (C) 2024 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 {
+    default_team: "trendy_team_platform_security",
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+// Main lib for Certificate Transparency services.
+java_library {
+    name: "service-networksecurity-pre-jarjar",
+    defaults: ["framework-system-server-module-defaults"],
+    visibility: ["//packages/modules/Connectivity:__subpackages__"],
+
+    srcs: [
+        "src/**/*.java",
+    ],
+
+    libs: [
+        "framework-connectivity-pre-jarjar",
+        "service-connectivity-pre-jarjar",
+    ],
+
+    // This is included in service-connectivity which is 30+
+    // TODO (b/293613362): allow APEXes to have service jars with higher min_sdk than the APEX
+    // (service-connectivity is only used on 31+) and use 31 here
+    min_sdk_version: "30",
+    sdk_version: "system_server_current",
+    apex_available: ["com.android.tethering"],
+}
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
new file mode 100644
index 0000000..8c53bf7
--- /dev/null
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2024 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.server.net.ct;
+
+import android.annotation.RequiresApi;
+import android.content.Context;
+import android.net.ct.ICertificateTransparencyManager;
+import android.os.Build;
+import android.util.Log;
+
+import com.android.net.ct.flags.Flags;
+import com.android.net.module.util.DeviceConfigUtils;
+
+/** Implementation of the Certificate Transparency service. */
+@RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
+public class CertificateTransparencyService extends ICertificateTransparencyManager.Stub {
+
+    private static final String TAG = "CertificateTransparency";
+    private static final String CERTIFICATE_TRANSPARENCY_ENABLED =
+            "certificate_transparency_service_enabled";
+
+    /**
+     * @return true if the CertificateTransparency service is enabled.
+     */
+    public static boolean enabled(Context context) {
+        // TODO: replace isTetheringFeatureEnabled with CT namespace flag.
+        return DeviceConfigUtils.isTetheringFeatureEnabled(
+                        context, CERTIFICATE_TRANSPARENCY_ENABLED)
+                && Flags.certificateTransparencyService();
+    }
+
+    /** Creates a new {@link CertificateTransparencyService} object. */
+    public CertificateTransparencyService(Context context) {}
+
+    /**
+     * Called by {@link com.android.server.ConnectivityServiceInitializer}.
+     *
+     * @see com.android.server.SystemService#onBootPhase
+     */
+    public void onBootPhase(int phase) {
+        Log.d(TAG, "CertificateTransparencyService#onBootPhase " + phase);
+    }
+}
diff --git a/service-t/Android.bp b/service-t/Android.bp
index 779f354..e00b7cf 100644
--- a/service-t/Android.bp
+++ b/service-t/Android.bp
@@ -59,6 +59,7 @@
         "framework-wifi",
         "service-connectivity-pre-jarjar",
         "service-nearby-pre-jarjar",
+        "service-networksecurity-pre-jarjar",
         "service-thread-pre-jarjar",
         service_remoteauth_pre_jarjar_lib,
         "ServiceConnectivityResources",
diff --git a/service-t/src/com/android/server/ConnectivityServiceInitializer.java b/service-t/src/com/android/server/ConnectivityServiceInitializer.java
index 1ac2f6e..5d23fdc 100644
--- a/service-t/src/com/android/server/ConnectivityServiceInitializer.java
+++ b/service-t/src/com/android/server/ConnectivityServiceInitializer.java
@@ -28,6 +28,7 @@
 import com.android.server.ethernet.EthernetService;
 import com.android.server.ethernet.EthernetServiceImpl;
 import com.android.server.nearby.NearbyService;
+import com.android.server.net.ct.CertificateTransparencyService;
 import com.android.server.thread.ThreadNetworkService;
 
 /**
@@ -43,6 +44,7 @@
     private final NearbyService mNearbyService;
     private final EthernetServiceImpl mEthernetServiceImpl;
     private final ThreadNetworkService mThreadNetworkService;
+    private final CertificateTransparencyService mCertificateTransparencyService;
 
     public ConnectivityServiceInitializer(Context context) {
         super(context);
@@ -55,6 +57,7 @@
         mNsdService = createNsdService(context);
         mNearbyService = createNearbyService(context);
         mThreadNetworkService = createThreadNetworkService(context);
+        mCertificateTransparencyService = createCertificateTransparencyService(context);
     }
 
     @Override
@@ -111,6 +114,10 @@
         if (mThreadNetworkService != null) {
             mThreadNetworkService.onBootPhase(phase);
         }
+
+        if (SdkLevel.isAtLeastV() && mCertificateTransparencyService != null) {
+            mCertificateTransparencyService.onBootPhase(phase);
+        }
     }
 
     /**
@@ -186,4 +193,13 @@
         }
         return new ThreadNetworkService(context);
     }
+
+    /** Return CertificateTransparencyService instance if enable, otherwise null. */
+    @Nullable
+    private CertificateTransparencyService createCertificateTransparencyService(
+            final Context context) {
+        return SdkLevel.isAtLeastV() && CertificateTransparencyService.enabled(context)
+                ? new CertificateTransparencyService(context)
+                : null;
+    }
 }
diff --git a/service/Android.bp b/service/Android.bp
index 1a0e045..c68f0b8 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -206,6 +206,7 @@
     },
     visibility: [
         "//packages/modules/Connectivity/service-t",
+        "//packages/modules/Connectivity/networksecurity:__subpackages__",
         "//packages/modules/Connectivity/tests:__subpackages__",
         "//packages/modules/Connectivity/thread/service:__subpackages__",
         "//packages/modules/Connectivity/thread/tests:__subpackages__",
@@ -247,6 +248,7 @@
         "service-connectivity-pre-jarjar",
         "service-connectivity-tiramisu-pre-jarjar",
         "service-nearby-pre-jarjar",
+        "service-networksecurity-pre-jarjar",
         service_remoteauth_pre_jarjar_lib,
         "service-thread-pre-jarjar",
     ],
@@ -315,6 +317,7 @@
         ":framework-connectivity-jarjar-rules",
         ":service-connectivity-jarjar-gen",
         ":service-nearby-jarjar-gen",
+        ":service-networksecurity-jarjar-gen",
         ":service-remoteauth-jarjar-gen",
         ":service-thread-jarjar-gen",
     ],
@@ -404,6 +407,24 @@
     visibility: ["//visibility:private"],
 }
 
+java_genrule {
+    name: "service-networksecurity-jarjar-gen",
+    tool_files: [
+        ":service-networksecurity-pre-jarjar{.jar}",
+        "jarjar-excludes.txt",
+    ],
+    tools: [
+        "jarjar-rules-generator",
+    ],
+    out: ["service_ct_jarjar_rules.txt"],
+    cmd: "$(location jarjar-rules-generator) " +
+        "$(location :service-networksecurity-pre-jarjar{.jar}) " +
+        "--prefix com.android.server.net.ct " +
+        "--excludes $(location jarjar-excludes.txt) " +
+        "--output $(out)",
+    visibility: ["//visibility:private"],
+}
+
 genrule {
     name: "statslog-connectivity-java-gen",
     tools: ["stats-log-api-gen"],