diff --git a/TMessagesProj/src/main/AndroidManifest.xml b/TMessagesProj/src/main/AndroidManifest.xml
index af71a62b1..22ddb19d6 100644
--- a/TMessagesProj/src/main/AndroidManifest.xml
+++ b/TMessagesProj/src/main/AndroidManifest.xml
@@ -2,7 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.telegram.messenger"
     android:versionCode="126"
-    android:versionName="1.3.4">
+    android:versionName="1.3.5">
     
     <supports-screens android:anyDensity="true"
     android:smallScreens="true"
diff --git a/TMessagesProj/src/main/java/org/telegram/messenger/HandshakeAction.java b/TMessagesProj/src/main/java/org/telegram/messenger/HandshakeAction.java
index 4303e7ca1..afa92044d 100644
--- a/TMessagesProj/src/main/java/org/telegram/messenger/HandshakeAction.java
+++ b/TMessagesProj/src/main/java/org/telegram/messenger/HandshakeAction.java
@@ -324,7 +324,7 @@ public class HandshakeAction extends Action implements TcpConnection.TcpConnecti
                     return;
                 }
 
-                if (!Utilities.isGoodPrime(dhInnerData.dh_prime)) {
+                if (!Utilities.isGoodPrime(dhInnerData.dh_prime, dhInnerData.g)) {
                     throw new RuntimeException("bad prime");
                 }
 
@@ -344,15 +344,17 @@ public class HandshakeAction extends Action implements TcpConnection.TcpConnecti
                     b[a] = (byte)(MessagesController.random.nextDouble() * 255);
                 }
 
-                BigInteger dhBI = new BigInteger(1, dhInnerData.dh_prime);
-                BigInteger i_g_b = BigInteger.valueOf(dhInnerData.g);
-                i_g_b = i_g_b.modPow(new BigInteger(1, b), dhBI);
-                byte[] g_b = i_g_b.toByteArray();
+                BigInteger p = new BigInteger(1, dhInnerData.dh_prime);
+                BigInteger g_b = BigInteger.valueOf(dhInnerData.g);
+                BigInteger g_a = new BigInteger(1, dhInnerData.g_a);
+                if (!Utilities.isGoodGaAndGb(g_a, g_b, p)) {
+                    throw new RuntimeException("bad prime");
+                }
 
-                BigInteger i_authKey = new BigInteger(1, dhInnerData.g_a);
-                i_authKey = i_authKey.modPow(new BigInteger(1, b), dhBI);
+                g_b = g_b.modPow(new BigInteger(1, b), p);
+                g_a = g_a.modPow(new BigInteger(1, b), p);
 
-                authKey = i_authKey.toByteArray();
+                authKey = g_a.toByteArray();
                 if (authKey.length > 256) {
                     byte[] correctedAuth = new byte[256];
                     System.arraycopy(authKey, 1, correctedAuth, 0, 256);
@@ -390,7 +392,7 @@ public class HandshakeAction extends Action implements TcpConnection.TcpConnecti
                 TLRPC.TL_client_DH_inner_data clientInnerData = new TLRPC.TL_client_DH_inner_data();
                 clientInnerData.nonce = authNonce;
                 clientInnerData.server_nonce = authServerNonce;
-                clientInnerData.g_b = g_b;
+                clientInnerData.g_b = g_b.toByteArray();
                 clientInnerData.retry_id = 0;
                 SerializedData os = new SerializedData();
                 clientInnerData.serializeToStream(os);
diff --git a/TMessagesProj/src/main/java/org/telegram/messenger/MessagesController.java b/TMessagesProj/src/main/java/org/telegram/messenger/MessagesController.java
index 62ae0bae0..8445b6066 100644
--- a/TMessagesProj/src/main/java/org/telegram/messenger/MessagesController.java
+++ b/TMessagesProj/src/main/java/org/telegram/messenger/MessagesController.java
@@ -4811,8 +4811,15 @@ public class MessagesController implements NotificationCenter.NotificationCenter
     }
 
     public void processAcceptedSecretChat(final TLRPC.EncryptedChat encryptedChat) {
+        BigInteger p = new BigInteger(1, MessagesStorage.secretPBytes);
         BigInteger i_authKey = new BigInteger(1, encryptedChat.g_a_or_b);
-        i_authKey = i_authKey.modPow(new BigInteger(1, encryptedChat.a_or_b), new BigInteger(1, MessagesStorage.secretPBytes));
+
+        if (!Utilities.isGoodGaAndGb(null, i_authKey, p)) {
+            declineSecretChat(encryptedChat.id);
+            return;
+        }
+
+        i_authKey = i_authKey.modPow(new BigInteger(1, encryptedChat.a_or_b), p);
 
         byte[] authKey = i_authKey.toByteArray();
         if (authKey.length > 256) {
@@ -4883,7 +4890,7 @@ public class MessagesController implements NotificationCenter.NotificationCenter
                 if (error == null) {
                     TLRPC.messages_DhConfig res = (TLRPC.messages_DhConfig)response;
                     if (response instanceof TLRPC.TL_messages_dhConfig) {
-                        if (!Utilities.isGoodPrime(res.p)) {
+                        if (!Utilities.isGoodPrime(res.p, res.g)) {
                             acceptingChats.remove(encryptedChat.id);
                             declineSecretChat(encryptedChat.id);
                             return;
@@ -4899,19 +4906,27 @@ public class MessagesController implements NotificationCenter.NotificationCenter
                         salt[a] = (byte)((byte)(random.nextDouble() * 255) ^ res.random[a]);
                     }
                     encryptedChat.a_or_b = salt;
-                    BigInteger i_g_b = BigInteger.valueOf(MessagesStorage.secretG);
-                    i_g_b = i_g_b.modPow(new BigInteger(1, salt), new BigInteger(1, MessagesStorage.secretPBytes));
-                    byte[] g_b = i_g_b.toByteArray();
-                    if (g_b.length > 256) {
-                        byte[] correctedAuth = new byte[256];
-                        System.arraycopy(g_b, 1, correctedAuth, 0, 256);
-                        g_b = correctedAuth;
+                    BigInteger p = new BigInteger(1, MessagesStorage.secretPBytes);
+                    BigInteger g_b = BigInteger.valueOf(MessagesStorage.secretG);
+                    g_b = g_b.modPow(new BigInteger(1, salt), p);
+                    BigInteger g_a = new BigInteger(1, encryptedChat.g_a);
+
+                    if (!Utilities.isGoodGaAndGb(g_a, g_b, p)) {
+                        acceptingChats.remove(encryptedChat.id);
+                        declineSecretChat(encryptedChat.id);
+                        return;
                     }
 
-                    BigInteger i_authKey = new BigInteger(1, encryptedChat.g_a);
-                    i_authKey = i_authKey.modPow(new BigInteger(1, salt), new BigInteger(1, MessagesStorage.secretPBytes));
+                    byte[] g_b_bytes = g_b.toByteArray();
+                    if (g_b_bytes.length > 256) {
+                        byte[] correctedAuth = new byte[256];
+                        System.arraycopy(g_b_bytes, 1, correctedAuth, 0, 256);
+                        g_b_bytes = correctedAuth;
+                    }
 
-                    byte[] authKey = i_authKey.toByteArray();
+                    g_a = g_a.modPow(new BigInteger(1, salt), p);
+
+                    byte[] authKey = g_a.toByteArray();
                     if (authKey.length > 256) {
                         byte[] correctedAuth = new byte[256];
                         System.arraycopy(authKey, authKey.length - 256, correctedAuth, 0, 256);
@@ -4930,7 +4945,7 @@ public class MessagesController implements NotificationCenter.NotificationCenter
                     encryptedChat.auth_key = authKey;
 
                     TLRPC.TL_messages_acceptEncryption req2 = new TLRPC.TL_messages_acceptEncryption();
-                    req2.g_b = g_b;
+                    req2.g_b = g_b_bytes;
                     req2.peer = new TLRPC.TL_inputEncryptedChat();
                     req2.peer.chat_id = encryptedChat.id;
                     req2.peer.access_hash = encryptedChat.access_hash;
@@ -4976,7 +4991,7 @@ public class MessagesController implements NotificationCenter.NotificationCenter
                 if (error == null) {
                     TLRPC.messages_DhConfig res = (TLRPC.messages_DhConfig)response;
                     if (response instanceof TLRPC.TL_messages_dhConfig) {
-                        if (!Utilities.isGoodPrime(res.p)) {
+                        if (!Utilities.isGoodPrime(res.p, res.g)) {
                             Utilities.RunOnUIThread(new Runnable() {
                                 @Override
                                 public void run() {
@@ -4996,6 +5011,7 @@ public class MessagesController implements NotificationCenter.NotificationCenter
                     for (int a = 0; a < 256; a++) {
                         salt[a] = (byte)((byte)(random.nextDouble() * 255) ^ res.random[a]);
                     }
+
                     BigInteger i_g_a = BigInteger.valueOf(MessagesStorage.secretG);
                     i_g_a = i_g_a.modPow(new BigInteger(1, salt), new BigInteger(1, MessagesStorage.secretPBytes));
                     byte[] g_a = i_g_a.toByteArray();
diff --git a/TMessagesProj/src/main/java/org/telegram/messenger/Utilities.java b/TMessagesProj/src/main/java/org/telegram/messenger/Utilities.java
index d86543bb9..04b4cb12a 100644
--- a/TMessagesProj/src/main/java/org/telegram/messenger/Utilities.java
+++ b/TMessagesProj/src/main/java/org/telegram/messenger/Utilities.java
@@ -100,7 +100,10 @@ public class Utilities {
         return new String(hexChars);
     }
 
-    public static boolean isGoodPrime(byte[] prime) {
+    public static boolean isGoodPrime(byte[] prime, int g) {
+        if (!(g >= 2 && g <= 7)) {
+            return false;
+        }
         String hex = bytesToHex(prime);
         for (String cached : goodPrimes) {
             if (cached.equals(hex)) {
@@ -121,6 +124,16 @@ public class Utilities {
         return true;
     }
 
+    public static boolean isGoodGaAndGb(BigInteger g_a, BigInteger g_b, BigInteger p) {
+        if (g_a != null && g_a.compareTo(BigInteger.valueOf(1)) != 1) {
+            return false;
+        }
+        if (g_b != null && p != null && g_b.compareTo(p.subtract(BigInteger.valueOf(1))) != -1) {
+            return false;
+        }
+        return true;
+    }
+
     public static TPFactorizedValue getFactorizedValue(long what) {
         long g = doPQNative(what);
         if (g > 1 && g < what) {