diff --git a/README.md b/README.md
index 564e8127..7fafbe9f 100644
--- a/README.md
+++ b/README.md
@@ -6,17 +6,37 @@ MIT-licensed pure-PHP implementations of an arbitrary-precision integer
 arithmetic library, fully PKCS#1 (v2.1) compliant RSA, DES, 3DES, RC4, Rijndael,
 AES, Blowfish, Twofish, SSH-1, SSH-2, SFTP, and X.509
 
-* [Download (1.0.5)](http://sourceforge.net/projects/phpseclib/files/phpseclib1.0.5.zip/download)
 * [Browse Git](https://github.com/phpseclib/phpseclib)
-* [Code Coverage Report](http://phpseclib.bantux.org/code_coverage/master/latest/)
-
-<img src="http://phpseclib.sourceforge.net/pear-icon.png" alt="PEAR Channel" width="16" height="16">
-PEAR Channel: [phpseclib.sourceforge.net](http://phpseclib.sourceforge.net/pear.htm)
+* [Code Coverage Report](https://coverage.phpseclib.org/master/latest/)
 
 ## Documentation
 
 * [Documentation / Manual](http://phpseclib.sourceforge.net/)
-* [API Documentation](http://phpseclib.bantux.org/api/master/) (generated by Sami)
+* [API Documentation](https://api.phpseclib.org/master/) (generated by Sami)
+
+## Branches
+
+### master
+
+* Development Branch
+* Unstable API
+* Do not use in production
+
+### 2.0
+
+* Modernized version of 1.0
+* Minimum PHP version: 5.3.3
+* PSR-4 autoloading with namespace rooted at `\phpseclib`
+* Install via Composer: `composer require phpseclib/phpseclib ~2.0`
+
+### 1.0
+
+* Long term support (LTS) release
+* PHP4 compatible
+* Composer compatible (PSR-0 autoloading)
+* Install using Composer: `composer require phpseclib/phpseclib ~1.0`
+* Install using PEAR: See [phpseclib PEAR Channel Documentation](http://phpseclib.sourceforge.net/pear.htm)
+* [Download 1.0.5 as ZIP](http://sourceforge.net/projects/phpseclib/files/phpseclib1.0.5.zip/download)
 
 ## Support
 
@@ -26,40 +46,29 @@ Need Support?
 * [Create a Support Ticket on GitHub](https://github.com/phpseclib/phpseclib/issues/new)
 * [Browse the Support Forum](http://www.frostjedi.com/phpbb/viewforum.php?f=46) (no longer in use)
 
-## Installing Development Dependencies
-
-Dependencies are managed via Composer.
-
-1. Download the [`composer.phar`](https://getcomposer.org/composer.phar) executable as per the
-   [Composer Download Instructions](https://getcomposer.org/download/), e.g. by running
-
-    ``` sh
-    curl -sS https://getcomposer.org/installer | php
-    ```
-
-2. Install Dependencies
-
-    ``` sh
-    php composer.phar install
-    ```
-
 ## Contributing
 
 1. Fork the Project
 
-2. Install Development Dependencies
+2. Ensure you have Composer installed (see [Composer Download Instructions](https://getcomposer.org/download/))
 
-3. Create a Feature Branch
+3. Install Development Dependencies
 
-4. (Recommended) Run the Test Suite
+    ``` sh
+    composer install
+    ```
+
+4. Create a Feature Branch
+
+5. (Recommended) Run the Test Suite
 
     ``` sh
     vendor/bin/phpunit
     ```
-5. (Recommended) Check whether your code conforms to our Coding Standards by running
+6. (Recommended) Check whether your code conforms to our Coding Standards by running
 
     ``` sh
     vendor/bin/phing -f build/build.xml sniff
     ```
 
-6. Send us a Pull Request
+7. Send us a Pull Request
diff --git a/phpseclib/File/X509.php b/phpseclib/File/X509.php
index ab1b6415..5286341e 100644
--- a/phpseclib/File/X509.php
+++ b/phpseclib/File/X509.php
@@ -885,6 +885,9 @@ class X509
             // "SET Secure Electronic Transaction Specification"
             // http://www.maithean.com/docs/set_bk3.pdf
             case '2.23.42.7.0': // id-set-hashedRootKey
+            // "Certificate Transparency"
+            // https://tools.ietf.org/html/rfc6962
+            case '1.3.6.1.4.1.11129.2.4.2':
                 return true;
 
             // CSR attributes
diff --git a/phpseclib/Net/SCP.php b/phpseclib/Net/SCP.php
index e1f31e3c..78d46a0f 100755
--- a/phpseclib/Net/SCP.php
+++ b/phpseclib/Net/SCP.php
@@ -304,6 +304,9 @@ class SCP
                     $response = Objects::getFunc($this->ssh, 'get_binary_packet');
                     switch ($response[SSH1::RESPONSE_TYPE]) {
                         case NET_SSH1_SMSG_STDOUT_DATA:
+                            if (strlen($response[SSH1::RESPONSE_DATA]) < 4) {
+                                return false;
+                            }
                             extract(unpack('Nlength', $response[SSH1::RESPONSE_DATA]));
                             return Strings::shift($response[SSH1::RESPONSE_DATA], $length);
                         case NET_SSH1_SMSG_STDERR_DATA:
diff --git a/phpseclib/Net/SFTP.php b/phpseclib/Net/SFTP.php
index 7d41893e..ab081a2a 100644
--- a/phpseclib/Net/SFTP.php
+++ b/phpseclib/Net/SFTP.php
@@ -376,7 +376,7 @@ class SFTP extends SSH2
         );
 
         if (!defined('NET_SFTP_QUEUE_SIZE')) {
-            define('NET_SFTP_QUEUE_SIZE', 50);
+            define('NET_SFTP_QUEUE_SIZE', 32);
         }
     }
 
@@ -392,7 +392,7 @@ class SFTP extends SSH2
     public function login($username)
     {
         $args = func_get_args();
-        if (!call_user_func_array(array(&$this, 'sublogin'), $args)) {
+        if (!call_user_func_array([&$this, 'sublogin'], $args)) {
             return false;
         }
 
@@ -476,11 +476,20 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_VERSION');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nversion', Strings::shift($response, 4)));
         $this->version = $version;
         while (!empty($response)) {
+            if (strlen($response) < 4) {
+                return false;
+            }
             extract(unpack('Nlength', Strings::shift($response, 4)));
             $key = Strings::shift($response, $length);
+            if (strlen($response) < 4) {
+                return false;
+            }
             extract(unpack('Nlength', Strings::shift($response, 4)));
             $value = Strings::shift($response, $length);
             $this->extensions[$key] = $value;
@@ -591,12 +600,15 @@ class SFTP extends SSH2
     private function logError($response, $status = -1)
     {
         if ($status == -1) {
+            if (strlen($response) < 4) {
+                return;
+            }
             extract(unpack('Nstatus', Strings::shift($response, 4)));
         }
 
         $error = $this->status_codes[$status];
 
-        if ($this->version > 2) {
+        if ($this->version > 2 || strlen($response) < 4) {
             extract(unpack('Nlength', Strings::shift($response, 4)));
             $this->sftp_errors[] = $error . ': ' . Strings::shift($response, $length);
         } else {
@@ -631,6 +643,9 @@ class SFTP extends SSH2
                     // should work on all SFTP versions since the only part of the SSH_FXP_NAME packet the following looks
                     // at is the first part and that part is defined the same in SFTP versions 3 through 6.
                     Strings::shift($response, 4); // skip over the count - it should be 1, anyway
+                    if (strlen($response) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nlength', Strings::shift($response, 4)));
                     return Strings::shift($response, $length);
                 case NET_SFTP_STATUS:
@@ -864,10 +879,19 @@ class SFTP extends SSH2
             $response = $this->get_sftp_packet();
             switch ($this->packet_type) {
                 case NET_SFTP_NAME:
+                    if (strlen($response) < 4) {
+                        return false;
+                    }
                     extract(unpack('Ncount', Strings::shift($response, 4)));
                     for ($i = 0; $i < $count; $i++) {
+                        if (strlen($response) < 4) {
+                            return false;
+                        }
                         extract(unpack('Nlength', Strings::shift($response, 4)));
                         $shortname = Strings::shift($response, $length);
+                        if (strlen($response) < 4) {
+                            return false;
+                        }
                         extract(unpack('Nlength', Strings::shift($response, 4)));
                         $longname = Strings::shift($response, $length);
                         $attributes = $this->parseAttributes($response);
@@ -894,6 +918,9 @@ class SFTP extends SSH2
                     }
                     break;
                 case NET_SFTP_STATUS:
+                    if (strlen($response) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nstatus', Strings::shift($response, 4)));
                     if ($status != NET_SFTP_STATUS_EOF) {
                         $this->logError($response, $status);
@@ -1487,6 +1514,9 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
@@ -1599,12 +1629,18 @@ class SFTP extends SSH2
                 throw new \UnexpectedValueException('Expected SSH_FXP_NAME or SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Ncount', Strings::shift($response, 4)));
         // the file isn't a symlink
         if (!$count) {
             return false;
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nlength', Strings::shift($response, 4)));
         return Strings::shift($response, $length);
     }
@@ -1639,7 +1675,11 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
+
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
             return false;
@@ -1702,6 +1742,9 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
@@ -1739,6 +1782,9 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             // presumably SSH_FX_NO_SUCH_FILE or SSH_FX_PERMISSION_DENIED?
@@ -1965,6 +2011,9 @@ class SFTP extends SSH2
                 throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
             }
 
+            if (strlen($response) < 4) {
+                return false;
+            }
             extract(unpack('Nstatus', Strings::shift($response, 4)));
             if ($status != NET_SFTP_STATUS_OK) {
                 $this->logError($response, $status);
@@ -1996,6 +2045,9 @@ class SFTP extends SSH2
             throw new \UnexpectedValueException('Expected SSH_FXP_STATUS');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
@@ -2170,6 +2222,15 @@ class SFTP extends SSH2
             return false;
         }
 
+        if (is_object($path)) {
+            // It's an object. Cast it as string before we check anything else.
+            $path = (string) $path;
+        }
+
+        if (!is_string($path) || $path == '') {
+            return false;
+        }
+
         $path = $this->realpath($path);
         if ($path === false) {
             return false;
@@ -2186,6 +2247,9 @@ class SFTP extends SSH2
         }
 
         // if $status isn't SSH_FX_OK it's probably SSH_FX_NO_SUCH_FILE or SSH_FX_PERMISSION_DENIED
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
@@ -2611,6 +2675,9 @@ class SFTP extends SSH2
         }
 
         // if $status isn't SSH_FX_OK it's probably SSH_FX_NO_SUCH_FILE or SSH_FX_PERMISSION_DENIED
+        if (strlen($response) < 4) {
+            return false;
+        }
         extract(unpack('Nstatus', Strings::shift($response, 4)));
         if ($status != NET_SFTP_STATUS_OK) {
             $this->logError($response, $status);
@@ -2638,6 +2705,10 @@ class SFTP extends SSH2
     private function parseAttributes(&$response)
     {
         $attr = [];
+        if (strlen($response) < 4) {
+            //user_error('Malformed file attributes');
+            return [];
+        }
         extract(unpack('Nflags', Strings::shift($response, 4)));
         // SFTPv4+ have a type field (a byte) that follows the above flag field
         foreach ($this->attributes as $key => $value) {
@@ -2652,9 +2723,17 @@ class SFTP extends SSH2
                     $attr['size'] = hexdec(Hex::encode(Strings::shift($response, 8)));
                     break;
                 case NET_SFTP_ATTR_UIDGID: // 0x00000002 (SFTPv3 only)
+                    if (strlen($response) < 8) {
+                        //user_error('Malformed file attributes');
+                        return $attr;
+                    }
                     $attr+= unpack('Nuid/Ngid', Strings::shift($response, 8));
                     break;
                 case NET_SFTP_ATTR_PERMISSIONS: // 0x00000004
+                    if (strlen($response) < 4) {
+                        //user_error('Malformed file attributes');
+                        return $attr;
+                    }
                     $attr+= unpack('Npermissions', Strings::shift($response, 4));
                     // mode == permissions; permissions was the original array key and is retained for bc purposes.
                     // mode was added because that's the more industry standard terminology
@@ -2665,13 +2744,29 @@ class SFTP extends SSH2
                     }
                     break;
                 case NET_SFTP_ATTR_ACCESSTIME: // 0x00000008
+                    if (strlen($response) < 8) {
+                        //user_error('Malformed file attributes');
+                        return $attr;
+                    }
                     $attr+= unpack('Natime/Nmtime', Strings::shift($response, 8));
                     break;
                 case NET_SFTP_ATTR_EXTENDED: // 0x80000000
+                    if (strlen($response) < 4) {
+                        //user_error('Malformed file attributes');
+                        return $attr;
+                    }
                     extract(unpack('Ncount', Strings::shift($response, 4)));
                     for ($i = 0; $i < $count; $i++) {
+                        if (strlen($response) < 4) {
+                            //user_error('Malformed file attributes');
+                            return $attr;
+                        }
                         extract(unpack('Nlength', Strings::shift($response, 4)));
                         $key = Strings::shift($response, $length);
+                        if (strlen($response) < 4) {
+                            //user_error('Malformed file attributes');
+                            return $attr;
+                        }
                         extract(unpack('Nlength', Strings::shift($response, 4)));
                         $attr[$key] = Strings::shift($response, $length);
                     }
@@ -2825,6 +2920,9 @@ class SFTP extends SSH2
             }
             $this->packet_buffer.= $temp;
         }
+        if (strlen($this->packet_buffer) < 4) {
+            return false;
+        }
         extract(unpack('Nlength', Strings::shift($this->packet_buffer, 4)));
         $tempLength = $length;
         $tempLength-= strlen($this->packet_buffer);
diff --git a/phpseclib/Net/SSH1.php b/phpseclib/Net/SSH1.php
index 4ea53369..edb4b5f3 100644
--- a/phpseclib/Net/SSH1.php
+++ b/phpseclib/Net/SSH1.php
@@ -575,28 +575,46 @@ class SSH1
 
         Strings::shift($response[self::RESPONSE_DATA], 4);
 
+        if (strlen($response[self::RESPONSE_DATA]) < 2) {
+            return false;
+        }
         $temp = unpack('nlen', Strings::shift($response[self::RESPONSE_DATA], 2));
         $server_key_public_exponent = new BigInteger(Strings::shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
         $this->server_key_public_exponent = $server_key_public_exponent;
 
+        if (strlen($response[self::RESPONSE_DATA]) < 2) {
+            return false;
+        }
         $temp = unpack('nlen', Strings::shift($response[self::RESPONSE_DATA], 2));
         $server_key_public_modulus = new BigInteger(Strings::shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
+
         $this->server_key_public_modulus = $server_key_public_modulus;
 
         Strings::shift($response[self::RESPONSE_DATA], 4);
 
+        if (strlen($response[self::RESPONSE_DATA]) < 2) {
+            return false;
+        }
         $temp = unpack('nlen', Strings::shift($response[self::RESPONSE_DATA], 2));
         $host_key_public_exponent = new BigInteger(Strings::shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
         $this->host_key_public_exponent = $host_key_public_exponent;
 
+        if (strlen($response[self::RESPONSE_DATA]) < 2) {
+            return false;
+        }
         $temp = unpack('nlen', Strings::shift($response[self::RESPONSE_DATA], 2));
         $host_key_public_modulus = new BigInteger(Strings::shift($response[self::RESPONSE_DATA], ceil($temp['len'] / 8)), 256);
+
         $this->host_key_public_modulus = $host_key_public_modulus;
 
         Strings::shift($response[self::RESPONSE_DATA], 4);
 
         // get a list of the supported ciphers
+        if (strlen($response[self::RESPONSE_DATA]) < 4) {
+            return false;
+        }
         extract(unpack('Nsupported_ciphers_mask', Strings::shift($response[self::RESPONSE_DATA], 4)));
+
         foreach ($this->supported_ciphers as $mask => $name) {
             if (($supported_ciphers_mask & (1 << $mask)) == 0) {
                 unset($this->supported_ciphers[$mask]);
@@ -604,6 +622,9 @@ class SSH1
         }
 
         // get a list of the supported authentications
+        if (strlen($response[self::RESPONSE_DATA]) < 4) {
+            return false;
+        }
         extract(unpack('Nsupported_authentications_mask', Strings::shift($response[self::RESPONSE_DATA], 4)));
         foreach ($this->supported_authentications as $mask => $name) {
             if (($supported_authentications_mask & (1 << $mask)) == 0) {
@@ -1085,7 +1106,11 @@ class SSH1
         }
 
         $start = strtok(microtime(), ' ') + strtok(''); // http://php.net/microtime#61838
-        $temp = unpack('Nlength', fread($this->fsock, 4));
+        $data = fread($this->fsock, 4);
+        if (strlen($data) < 4) {
+            return false;
+        }
+        $temp = unpack('Nlength', $data);
 
         $padding_length = 8 - ($temp['length'] & 7);
         $length = $temp['length'] + $padding_length;
@@ -1106,6 +1131,9 @@ class SSH1
         $type = $raw[$padding_length];
         $data = substr($raw, $padding_length + 1, -4);
 
+        if (strlen($raw) < 4) {
+            return false;
+        }
         $temp = unpack('Ncrc', substr($raw, -4));
 
         //if ( $temp['crc'] != $this->crc($padding . $type . $data) ) {
diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index 9a38f561..9ce0203e 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -1021,7 +1021,10 @@ class SSH2
 
         if (!is_resource($this->fsock)) {
             $start = microtime(true);
-            $this->fsock = @fsockopen($this->host, $this->port, $errno, $errstr, $this->curTimeout);
+            // with stream_select a timeout of 0 means that no timeout takes place;
+            // with fsockopen a timeout of 0 means that you instantly timeout
+            // to resolve this incompatibility a timeout of 100,000 will be used for fsockopen if timeout is 0
+            $this->fsock = @fsockopen($this->host, $this->port, $errno, $errstr, $this->curTimeout == 0 ? 100000 : $this->curTimeout);
             if (!$this->fsock) {
                 $host = $this->host . ':' . $this->port;
                 throw new \RuntimeException(rtrim("Cannot connect to $host. Error $errno. $errstr"));
@@ -1119,7 +1122,7 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
-        if (ord($response[0]) != NET_SSH2_MSG_KEXINIT) {
+        if (!strlen($response) || ord($response[0]) != NET_SSH2_MSG_KEXINIT) {
             throw new \UnexpectedValueException('Expected SSH_MSG_KEXINIT');
         }
 
@@ -1318,37 +1321,71 @@ class SSH2
         Strings::shift($response, 1); // skip past the message number (it should be SSH_MSG_KEXINIT)
         $server_cookie = Strings::shift($response, 16);
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->kex_algorithms = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->server_host_key_algorithms = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->encryption_algorithms_client_to_server = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->encryption_algorithms_server_to_client = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->mac_algorithms_client_to_server = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->mac_algorithms_server_to_client = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->compression_algorithms_client_to_server = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->compression_algorithms_server_to_client = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->languages_client_to_server = explode(',', Strings::shift($response, $temp['length']));
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->languages_server_to_client = explode(',', Strings::shift($response, $temp['length']));
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Cfirst_kex_packet_follows', Strings::shift($response, 1)));
+
         $first_kex_packet_follows = $first_kex_packet_follows != 0;
 
         // the sending of SSH2_MSG_KEXINIT could go in one of two places.  this is the second place.
@@ -1447,10 +1484,16 @@ class SSH2
                     return false;
                 }
 
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('NprimeLength', Strings::shift($response, 4)));
                 $primeBytes = Strings::shift($response, $primeLength);
                 $prime = new BigInteger($primeBytes, -256);
 
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('NgLength', Strings::shift($response, 4)));
                 $gBytes = Strings::shift($response, $gLength);
                 $g = new BigInteger($gBytes, -256);
@@ -1531,24 +1574,42 @@ class SSH2
         if ($response === false) {
             throw new \RuntimeException('Connection closed by server');
         }
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         if ($type != $serverKexReplyMessage) {
             throw new \UnexpectedValueException('Expected SSH_MSG_KEXDH_REPLY');
         }
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->server_public_host_key = $server_public_host_key = Strings::shift($response, $temp['length']);
 
+        if (strlen($server_public_host_key) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
         $public_key_format = Strings::shift($server_public_host_key, $temp['length']);
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $fBytes = Strings::shift($response, $temp['length']);
 
+        if (strlen($response) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($response, 4));
         $this->signature = Strings::shift($response, $temp['length']);
 
+        if (strlen($this->signature) < 4) {
+            return false;
+        }
         $temp = unpack('Nlength', Strings::shift($this->signature, 4));
         $this->signature_format = Strings::shift($this->signature, $temp['length']);
 
@@ -1618,6 +1679,9 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         if ($type != NET_SSH2_MSG_NEWKEYS) {
@@ -1952,6 +2016,9 @@ class SSH2
                 throw new \RuntimeException('Connection closed by server');
             }
 
+            if (strlen($response) < 4) {
+                return false;
+            }
             extract(unpack('Ctype', Strings::shift($response, 1)));
 
             if ($type != NET_SSH2_MSG_SERVICE_ACCEPT) {
@@ -1999,6 +2066,9 @@ class SSH2
                 throw new \RuntimeException('Connection closed by server');
             }
 
+            if (!strlen($response)) {
+                return false;
+            }
             extract(unpack('Ctype', Strings::shift($response, 1)));
 
             switch ($type) {
@@ -2053,6 +2123,9 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         switch ($type) {
@@ -2060,14 +2133,25 @@ class SSH2
                 if (defined('NET_SSH2_LOGGING')) {
                     $this->message_number_log[count($this->message_number_log) - 1] = 'NET_SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ';
                 }
+
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 $this->errors[] = 'SSH_MSG_USERAUTH_PASSWD_CHANGEREQ: ' . utf8_decode(Strings::shift($response, $length));
+
                 return $this->disconnect_helper(NET_SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER);
             case NET_SSH2_MSG_USERAUTH_FAILURE:
                 // can we use keyboard-interactive authentication?  if not then either the login is bad or the server employees
                 // multi-factor authentication
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 $auth_methods = explode(',', Strings::shift($response, $length));
+                if (!strlen($response)) {
+                    return false;
+                }
                 extract(unpack('Cpartial_success', Strings::shift($response, 1)));
                 $partial_success = $partial_success != 0;
 
@@ -2142,16 +2226,31 @@ class SSH2
             }
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         switch ($type) {
             case NET_SSH2_MSG_USERAUTH_INFO_REQUEST:
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 Strings::shift($response, $length); // name; may be empty
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 Strings::shift($response, $length); // instruction; may be empty
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 Strings::shift($response, $length); // language tag; may be empty
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nnum_prompts', Strings::shift($response, 4)));
 
                 for ($i = 0; $i < count($responses); $i++) {
@@ -2166,6 +2265,9 @@ class SSH2
 
                 if (isset($this->keyboard_requests_responses)) {
                     for ($i = 0; $i < $num_prompts; $i++) {
+                        if (strlen($response) < 4) {
+                            return false;
+                        }
                         extract(unpack('Nlength', Strings::shift($response, 4)));
                         // prompt - ie. "Password: "; must not be empty
                         $prompt = Strings::shift($response, $length);
@@ -2311,12 +2413,19 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         switch ($type) {
             case NET_SSH2_MSG_USERAUTH_FAILURE:
+                if (strlen($response) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($response, 4)));
                 $this->errors[] = 'SSH_MSG_USERAUTH_FAILURE: ' . Strings::shift($response, $length);
+
                 return false;
             case NET_SSH2_MSG_USERAUTH_PK_OK:
                 // we'll just take it on faith that the public key blob and the public key algorithm name are as
@@ -2345,6 +2454,9 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         extract(unpack('Ctype', Strings::shift($response, 1)));
 
         switch ($type) {
@@ -2401,7 +2513,12 @@ class SSH2
         $this->is_timeout = false;
         $this->stdErrorLog = '';
 
-        if (!($this->bitmap & self::MASK_LOGIN)) {
+        if (!$this->isAuthenticated()) {
+            return false;
+        }
+
+        if ($this->in_request_pty_exec) {
+            user_error('If you want to run multiple exec()\'s you will need to disable (and re-enable if appropriate) a PTY for each one.');
             return false;
         }
 
@@ -2463,6 +2580,9 @@ class SSH2
                 throw new \RuntimeException('Connection closed by server');
             }
 
+            if (!strlen($response)) {
+                return false;
+            }
             list(, $type) = unpack('C', Strings::shift($response, 1));
 
             switch ($type) {
@@ -2600,6 +2720,9 @@ class SSH2
             throw new \RuntimeException('Connection closed by server');
         }
 
+        if (!strlen($response)) {
+            return false;
+        }
         list(, $type) = unpack('C', Strings::shift($response, 1));
 
         switch ($type) {
@@ -2694,7 +2817,7 @@ class SSH2
         $this->curTimeout = $this->timeout;
         $this->is_timeout = false;
 
-        if (!($this->bitmap & self::MASK_LOGIN)) {
+        if (!$this->isAuthenticated()) {
             throw new \RuntimeException('Operation disallowed prior to login()');
         }
 
@@ -2735,7 +2858,7 @@ class SSH2
      */
     public function write($cmd)
     {
-        if (!($this->bitmap & self::MASK_LOGIN)) {
+        if (!$this->isAuthenticated()) {
             throw new \RuntimeException('Operation disallowed prior to login()');
         }
 
@@ -2930,6 +3053,9 @@ class SSH2
             $raw = $this->decrypt->decrypt($raw);
         }
 
+        if (strlen($raw) < 5) {
+            return false;
+        }
         extract(unpack('Npacket_length/Cpadding_length', Strings::shift($raw, 5)));
 
         $remaining_length = $packet_length + 4 - $this->decrypt_block_size;
@@ -3001,6 +3127,9 @@ class SSH2
         switch (ord($payload[0])) {
             case NET_SSH2_MSG_DISCONNECT:
                 Strings::shift($payload, 1);
+                if (strlen($payload) < 8) {
+                    return false;
+                }
                 extract(unpack('Nreason_code/Nlength', Strings::shift($payload, 8)));
                 $this->errors[] = 'SSH_MSG_DISCONNECT: ' . $this->disconnect_reasons[$reason_code] . "\r\n" . utf8_decode(Strings::shift($payload, $length));
                 $this->bitmap = 0;
@@ -3010,6 +3139,9 @@ class SSH2
                 break;
             case NET_SSH2_MSG_DEBUG:
                 Strings::shift($payload, 2);
+                if (strlen($payload) < 4) {
+                    return false;
+                }
                 extract(unpack('Nlength', Strings::shift($payload, 4)));
                 $this->errors[] = 'SSH_MSG_DEBUG: ' . utf8_decode(Strings::shift($payload, $length));
                 $payload = $this->get_binary_packet();
@@ -3027,17 +3159,23 @@ class SSH2
         }
 
         // see http://tools.ietf.org/html/rfc4252#section-5.4; only called when the encryption has been activated and when we haven't already logged in
-        if (($this->bitmap & self::MASK_CONNECTED) && !($this->bitmap & self::MASK_LOGIN) && ord($payload[0]) == NET_SSH2_MSG_USERAUTH_BANNER) {
+        if (($this->bitmap & self::MASK_CONNECTED) && !$this->isAuthenticated() && ord($payload[0]) == NET_SSH2_MSG_USERAUTH_BANNER) {
             Strings::shift($payload, 1);
+            if (strlen($payload) < 4) {
+                return false;
+            }
             extract(unpack('Nlength', Strings::shift($payload, 4)));
             $this->banner_message = utf8_decode(Strings::shift($payload, $length));
             $payload = $this->get_binary_packet();
         }
 
         // only called when we've already logged in
-        if (($this->bitmap & self::MASK_CONNECTED) && ($this->bitmap & self::MASK_LOGIN)) {
+        if (($this->bitmap & self::MASK_CONNECTED) && $this->isAuthenticated()) {
             switch (ord($payload[0])) {
                 case NET_SSH2_MSG_GLOBAL_REQUEST: // see http://tools.ietf.org/html/rfc4254#section-4
+                    if (strlen($payload) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nlength', Strings::shift($payload, 4)));
                     $this->errors[] = 'SSH_MSG_GLOBAL_REQUEST: ' . Strings::shift($payload, $length);
 
@@ -3049,8 +3187,14 @@ class SSH2
                     break;
                 case NET_SSH2_MSG_CHANNEL_OPEN: // see http://tools.ietf.org/html/rfc4254#section-5.1
                     Strings::shift($payload, 1);
+                    if (strlen($payload) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nlength', Strings::shift($payload, 4)));
                     $data = Strings::shift($payload, $length);
+                    if (strlen($payload) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nserver_channel', Strings::shift($payload, 4)));
                     switch ($data) {
                         case 'auth-agent':
@@ -3058,6 +3202,9 @@ class SSH2
                             if (isset($this->agent)) {
                                 $new_channel = self::CHANNEL_AGENT_FORWARD;
 
+                                if (strlen($payload) < 8) {
+                                    return false;
+                                }
                                 extract(unpack('Nremote_window_size', Strings::shift($payload, 4)));
                                 extract(unpack('Nremote_maximum_packet_size', Strings::shift($payload, 4)));
 
@@ -3103,8 +3250,12 @@ class SSH2
                     break;
                 case NET_SSH2_MSG_CHANNEL_WINDOW_ADJUST:
                     Strings::shift($payload, 1);
+                    if (strlen($payload) < 8) {
+                        return false;
+                    }
                     extract(unpack('Nchannel', Strings::shift($payload, 4)));
                     extract(unpack('Nwindow_size', Strings::shift($payload, 4)));
+
                     $this->window_size_client_to_server[$channel]+= $window_size;
 
                     $payload = ($this->bitmap & self::MASK_WINDOW_ADJUST) ? true : $this->get_binary_packet();
@@ -3168,6 +3319,10 @@ class SSH2
      */
     public function disablePTY()
     {
+        if ($this->in_request_pty_exec) {
+            $this->_close_channel(self::CHANNEL_EXEC);
+            $this->in_request_pty_exec = false;
+        }
         $this->request_pty = false;
     }
 
@@ -3233,8 +3388,14 @@ class SSH2
                 return '';
             }
 
+            if (!strlen($response)) {
+                return false;
+            }
             extract(unpack('Ctype', Strings::shift($response, 1)));
 
+            if (strlen($response) < 4) {
+                return false;
+            }
             if ($type == NET_SSH2_MSG_CHANNEL_OPEN) {
                 extract(unpack('Nlength', Strings::shift($response, 4)));
             } else {
@@ -3258,15 +3419,26 @@ class SSH2
                     case NET_SSH2_MSG_CHANNEL_OPEN:
                         switch ($type) {
                             case NET_SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
+                                if (strlen($response) < 4) {
+                                    return false;
+                                }
                                 extract(unpack('Nserver_channel', Strings::shift($response, 4)));
                                 $this->server_channels[$channel] = $server_channel;
+                                if (strlen($response) < 4) {
+                                    return false;
+                                }
                                 extract(unpack('Nwindow_size', Strings::shift($response, 4)));
+
                                 if ($window_size < 0) {
                                     $window_size&= 0x7FFFFFFF;
                                     $window_size+= 0x80000000;
                                 }
                                 $this->window_size_client_to_server[$channel] = $window_size;
+                                if (strlen($response) < 4) {
+                                     return false;
+                                }
                                 $temp = unpack('Npacket_size_client_to_server', Strings::shift($response, 4));
+
                                 $this->packet_size_client_to_server[$channel] = $temp['packet_size_client_to_server'];
                                 $result = $client_channel == $channel ? true : $this->get_channel_packet($client_channel, $skip_extended);
                                 $this->on_channel_open();
@@ -3305,6 +3477,9 @@ class SSH2
                         $this->send_channel_packet($channel, chr(0));
                     }
                     */
+                    if (strlen($response) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nlength', Strings::shift($response, 4)));
                     $data = Strings::shift($response, $length);
 
@@ -3331,8 +3506,12 @@ class SSH2
                     }
                     */
                     // currently, there's only one possible value for $data_type_code: NET_SSH2_EXTENDED_DATA_STDERR
+                    if (strlen($response) < 8) {
+                        return false;
+                    }
                     extract(unpack('Ndata_type_code/Nlength', Strings::shift($response, 8)));
                     $data = Strings::shift($response, $length);
+
                     $this->stdErrorLog.= $data;
                     if ($skip_extended || $this->quiet_mode) {
                         break;
@@ -3346,13 +3525,22 @@ class SSH2
                     $this->channel_buffers[$channel][] = $data;
                     break;
                 case NET_SSH2_MSG_CHANNEL_REQUEST:
+                    if (strlen($response) < 4) {
+                        return false;
+                    }
                     extract(unpack('Nlength', Strings::shift($response, 4)));
                     $value = Strings::shift($response, $length);
                     switch ($value) {
                         case 'exit-signal':
                             Strings::shift($response, 1);
+                            if (strlen($response) < 4) {
+                                return false;
+                            }
                             extract(unpack('Nlength', Strings::shift($response, 4)));
                             $this->errors[] = 'SSH_MSG_CHANNEL_REQUEST (exit-signal): ' . Strings::shift($response, $length);
+                            if (strlen($response) < 4) {
+                                return false;
+                            }
                             Strings::shift($response, 1);
                             extract(unpack('Nlength', Strings::shift($response, 4)));
                             if ($length) {
@@ -3366,7 +3554,11 @@ class SSH2
 
                             break;
                         case 'exit-status':
+                            if (strlen($response) < 5) {
+                                return false;
+                            }
                             extract(unpack('Cfalse/Nexit_status', Strings::shift($response, 5)));
+
                             $this->exit_status = $exit_status;
 
                             // "The client MAY ignore these messages."
@@ -3978,6 +4170,9 @@ class SSH2
         $signature = $this->signature;
         $server_public_host_key = $this->server_public_host_key;
 
+        if (strlen($server_public_host_key) < 4) {
+            return false;
+        }
         extract(unpack('Nlength', Strings::shift($server_public_host_key, 4)));
         Strings::shift($server_public_host_key, $length);
 
@@ -3993,15 +4188,27 @@ class SSH2
             case 'ssh-dss':
                 $zero = new BigInteger();
 
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $p = new BigInteger(Strings::shift($server_public_host_key, $temp['length']), -256);
 
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $q = new BigInteger(Strings::shift($server_public_host_key, $temp['length']), -256);
 
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $g = new BigInteger(Strings::shift($server_public_host_key, $temp['length']), -256);
 
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $y = new BigInteger(Strings::shift($server_public_host_key, $temp['length']), -256);
 
@@ -4048,15 +4255,24 @@ class SSH2
 
                 break;
             case 'ssh-rsa':
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $e = new BigInteger(Strings::shift($server_public_host_key, $temp['length']), -256);
 
+                if (strlen($server_public_host_key) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($server_public_host_key, 4));
                 $rawN = Strings::shift($server_public_host_key, $temp['length']);
                 $n = new BigInteger($rawN, -256);
                 $nLength = strlen(ltrim($rawN, "\0"));
 
                 /*
+                if (strlen($signature) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($signature, 4));
                 $signature = Strings::shift($signature, $temp['length']);
 
@@ -4069,6 +4285,9 @@ class SSH2
                 }
                 */
 
+                if (strlen($signature) < 4) {
+                    return false;
+                }
                 $temp = unpack('Nlength', Strings::shift($signature, 4));
                 $s = new BigInteger(Strings::shift($signature, $temp['length']), 256);