diff --git a/networksecurity/service/Android.bp b/networksecurity/service/Android.bp
index d7aacdb..3c964e5 100644
--- a/networksecurity/service/Android.bp
+++ b/networksecurity/service/Android.bp
@@ -32,6 +32,7 @@
         "framework-connectivity-pre-jarjar",
         "service-connectivity-pre-jarjar",
         "framework-statsd.stubs.module_lib",
+        "ServiceConnectivityResources",
     ],
 
     static_libs: [
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
index e6f1379..f1b9a4f 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyJob.java
@@ -38,6 +38,7 @@
     private final DataStore mDataStore;
     private final CertificateTransparencyDownloader mCertificateTransparencyDownloader;
     private final CompatibilityVersion mCompatVersion;
+    private final SignatureVerifier mSignatureVerifier;
     private final AlarmManager mAlarmManager;
     private final PendingIntent mPendingIntent;
 
@@ -49,11 +50,13 @@
             Context context,
             DataStore dataStore,
             CertificateTransparencyDownloader certificateTransparencyDownloader,
-            CompatibilityVersion compatVersion) {
+            CompatibilityVersion compatVersion,
+            SignatureVerifier signatureVerifier) {
         mContext = context;
         mDataStore = dataStore;
         mCertificateTransparencyDownloader = certificateTransparencyDownloader;
         mCompatVersion = compatVersion;
+        mSignatureVerifier = signatureVerifier;
 
         mAlarmManager = context.getSystemService(AlarmManager.class);
         mPendingIntent =
@@ -127,6 +130,7 @@
     private void startDependencies() {
         mDataStore.load();
         mCertificateTransparencyDownloader.addCompatibilityVersion(mCompatVersion);
+        mSignatureVerifier.loadAllowedKeys();
         mContext.registerReceiver(
                 mCertificateTransparencyDownloader,
                 new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE),
@@ -139,6 +143,7 @@
 
     private void stopDependencies() {
         mContext.unregisterReceiver(mCertificateTransparencyDownloader);
+        mSignatureVerifier.clearAllowedKeys();
         mCertificateTransparencyDownloader.clearCompatibilityVersions();
         mDataStore.delete();
 
diff --git a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
index a71ff7c..2e910b2 100644
--- a/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
+++ b/networksecurity/service/src/com/android/server/net/ct/CertificateTransparencyService.java
@@ -52,6 +52,7 @@
     public CertificateTransparencyService(Context context) {
         DataStore dataStore = new DataStore(Config.PREFERENCES_FILE);
 
+        SignatureVerifier signatureVerifier = new SignatureVerifier(context);
         mCertificateTransparencyJob =
                 new CertificateTransparencyJob(
                         context,
@@ -60,13 +61,14 @@
                                 context,
                                 dataStore,
                                 new DownloadHelper(context),
-                                new SignatureVerifier(context),
+                                signatureVerifier,
                                 new CertificateTransparencyLoggerImpl(dataStore)),
                         new CompatibilityVersion(
                                 Config.COMPATIBILITY_VERSION,
                                 Config.URL_SIGNATURE,
                                 Config.URL_LOG_LIST,
-                                Config.CT_ROOT_DIRECTORY_PATH));
+                                Config.CT_ROOT_DIRECTORY_PATH),
+                        signatureVerifier);
     }
 
     /**
diff --git a/networksecurity/service/src/com/android/server/net/ct/PemReader.java b/networksecurity/service/src/com/android/server/net/ct/PemReader.java
new file mode 100644
index 0000000..56b3973
--- /dev/null
+++ b/networksecurity/service/src/com/android/server/net/ct/PemReader.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2025 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 java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.security.GeneralSecurityException;
+import java.security.KeyFactory;
+import java.security.PublicKey;
+import java.security.spec.KeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.ArrayList;
+import java.util.Base64;
+import java.util.Collection;
+
+/** Utility class to read keys in PEM format. */
+class PemReader {
+
+    private static final String BEGIN = "-----BEGIN";
+    private static final String END = "-----END";
+
+    /**
+     * Parse the provided input stream and return the list of keys from the stream.
+     *
+     * @param input the input stream
+     * @return the keys
+     */
+    public static Collection<PublicKey> readKeysFrom(InputStream input)
+            throws IOException, GeneralSecurityException {
+        KeyFactory instance = KeyFactory.getInstance("RSA");
+        Collection<PublicKey> keys = new ArrayList<>();
+
+        try (BufferedReader reader = new BufferedReader(new InputStreamReader(input))) {
+            String line = reader.readLine();
+            while (line != null) {
+                if (line.startsWith(BEGIN)) {
+                    keys.add(instance.generatePublic(readNextKey(reader)));
+                } else {
+                    throw new IOException("Unexpected line in the reader: " + line);
+                }
+                line = reader.readLine();
+            }
+        } catch (IllegalArgumentException e) {
+            throw new GeneralSecurityException("Invalid public key base64 encoding", e);
+        }
+
+        return keys;
+    }
+
+    private static KeySpec readNextKey(BufferedReader reader) throws IOException {
+        StringBuilder publicKeyBuilder = new StringBuilder();
+
+        String line = reader.readLine();
+        while (line != null) {
+            if (line.startsWith(END)) {
+                return new X509EncodedKeySpec(
+                        Base64.getDecoder().decode(publicKeyBuilder.toString()));
+            } else {
+                publicKeyBuilder.append(line);
+            }
+            line = reader.readLine();
+        }
+
+        throw new IOException("Unexpected end of the reader");
+    }
+}
diff --git a/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java b/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java
index 6040ef6..87a4973 100644
--- a/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java
+++ b/networksecurity/service/src/com/android/server/net/ct/SignatureVerifier.java
@@ -30,6 +30,9 @@
 
 import androidx.annotation.VisibleForTesting;
 
+import com.android.connectivity.resources.R;
+import com.android.server.connectivity.ConnectivityResources;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.security.GeneralSecurityException;
@@ -39,21 +42,39 @@
 import java.security.Signature;
 import java.security.spec.X509EncodedKeySpec;
 import java.util.Base64;
+import java.util.HashSet;
 import java.util.Optional;
+import java.util.Set;
 
 /** Verifier of the log list signature. */
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 public class SignatureVerifier {
 
-    private final Context mContext;
     private static final String TAG = "SignatureVerifier";
 
+    private final Context mContext;
+
     @NonNull private Optional<PublicKey> mPublicKey = Optional.empty();
 
+    private final Set<PublicKey> mAllowedKeys = new HashSet<>();
+
     public SignatureVerifier(Context context) {
         mContext = context;
     }
 
+    void loadAllowedKeys() {
+        try (InputStream input =
+                new ConnectivityResources(mContext).get().openRawResource(R.raw.ct_public_keys)) {
+            mAllowedKeys.addAll(PemReader.readKeysFrom(input));
+        } catch (GeneralSecurityException | IOException e) {
+            Log.e(TAG, "Error loading public keys", e);
+        }
+    }
+
+    void clearAllowedKeys() {
+        mAllowedKeys.clear();
+    }
+
     @VisibleForTesting
     Optional<PublicKey> getPublicKey() {
         return mPublicKey;
@@ -82,7 +103,11 @@
     }
 
     @VisibleForTesting
-    void setPublicKey(PublicKey publicKey) {
+    void setPublicKey(PublicKey publicKey) throws GeneralSecurityException {
+        if (!mAllowedKeys.contains(publicKey)) {
+            // TODO(b/400704086): add logging for this failure.
+            throw new GeneralSecurityException("Public key not in allowlist");
+        }
         mPublicKey = Optional.of(publicKey);
     }
 
@@ -105,21 +130,18 @@
 
             byte[] signatureBytes = signatureStream.readAllBytes();
             statusBuilder.setSignature(new String(signatureBytes));
-            try {
-                byte[] decodedSigBytes = Base64.getDecoder().decode(signatureBytes);
 
-                if (!verifier.verify(decodedSigBytes)) {
-                    // Leave the UpdateState as UNKNOWN_STATE if successful as there are other
-                    // potential failures past the signature verification step
-                    statusBuilder.setState(SIGNATURE_VERIFICATION_FAILED);
-                }
-            } catch (IllegalArgumentException e) {
-                Log.w(TAG, "Invalid signature base64 encoding", e);
-                statusBuilder.setState(SIGNATURE_INVALID);
-                return statusBuilder.build();
+            if (!verifier.verify(Base64.getDecoder().decode(signatureBytes))) {
+                // Leave the UpdateState as UNKNOWN_STATE if successful as there are other
+                // potential failures past the signature verification step
+                statusBuilder.setState(SIGNATURE_VERIFICATION_FAILED);
             }
+        } catch (IllegalArgumentException e) {
+            Log.w(TAG, "Invalid signature base64 encoding", e);
+            statusBuilder.setState(SIGNATURE_INVALID);
+            return statusBuilder.build();
         } catch (InvalidKeyException e) {
-            Log.e(TAG, "Signature invalid for log list verification", e);
+            Log.e(TAG, "Key invalid for log list verification", e);
             statusBuilder.setState(SIGNATURE_INVALID);
             return statusBuilder.build();
         } catch (IOException | GeneralSecurityException e) {
@@ -135,4 +157,9 @@
 
         return statusBuilder.build();
     }
+
+    @VisibleForTesting
+    boolean addAllowedKey(PublicKey publicKey) {
+        return mAllowedKeys.add(publicKey);
+    }
 }