diff --git a/mtproto.php b/mtproto.php
index a1385074..2155173f 100755
--- a/mtproto.php
+++ b/mtproto.php
@@ -231,8 +231,7 @@ class Session
         pyjslib_printnl('Requesting pq');
         $ResPQ = $this->method_call('req_pq', ['nonce' => $nonce]);
         $server_nonce = $ResPQ['server_nonce'];
-        $public_key_fingerprint = $ResPQ['server_public_key_fingerprints'][0];
-        var_dump($public_key_fingerprint);
+        $public_key_fingerprint = (int)$ResPQ['server_public_key_fingerprints'][0];
         $pq_bytes = $ResPQ['pq'];
 
         $pq = new \phpseclib\Math\BigInteger($pq_bytes, 256);
@@ -244,8 +243,8 @@ class Session
         }
         assert(($pq->equals($p->multiply($q))) && ($p < $q));
         pyjslib_printnl(sprintf('Factorization %s = %s * %s', $pq, $p, $q));
-        $p_bytes = $this->struct->pack('>Q', (string) $p);
-        $q_bytes = $this->struct->pack('>Q', (string) $q);
+        $p_bytes = $this->struct->pack('>I', (string) $p);
+        $q_bytes = $this->struct->pack('>I', (string) $q);
         $f = file_get_contents(__DIR__.'/rsa.pub');
         $key = new \phpseclib\Crypt\RSA();
         $key->load($f);
diff --git a/mtproto.py b/mtproto.py
index fe97fd28..a8e42bf0 100644
--- a/mtproto.py
+++ b/mtproto.py
@@ -166,12 +166,13 @@ class Session:
                                 nonce=nonce,
                                 server_nonce=server_nonce,
                                 new_nonce=new_nonce)
-
+        print(len(data), len(p_bytes))
         sha_digest = SHA.new(data).digest()
         random_bytes = os.urandom(255-len(data)-len(sha_digest))
+        print(len(sha_digest), len(data), len(random_bytes))
         to_encrypt = sha_digest + data + random_bytes
         encrypted_data = key.encrypt(to_encrypt, 0)[0]
-        print("Starting Diffie Hellman key exchange")
+        print("Starting Diffie Hellman key exchange", len(to_encrypt))
         server_dh_params = self.method_call('req_DH_params',
                                             nonce=nonce,
                                             server_nonce=server_nonce,
diff --git a/prime.php b/prime.php
index 37ba39f3..849fe4ee 100644
--- a/prime.php
+++ b/prime.php
@@ -177,11 +177,13 @@ class PrimeModule
     public function primefactors($pq, $sort = false)
     {
         if (function_exists('shell_exec')) {
-            // Use the python version.
-            $res = explode(' ', shell_exec('python getpq.py '.$pq));
-            if (count($res) == 2) {
-                return $res;
-            }
+            try {
+                // Use the python version.
+                $res = explode(' ', shell_exec('python getpq.py '.$pq));
+                if (count($res) == 2) {
+                    return $res;
+                }
+            } catch (ErrorException $e) { ; };
         }
         // Else do factorization with wolfram alpha :)))))
         $query = 'Do prime factorization of '.$pq;