diff --git a/phpseclib/Crypt/DES.php b/phpseclib/Crypt/DES.php
index 0d6dd00e..6a6d3389 100644
--- a/phpseclib/Crypt/DES.php
+++ b/phpseclib/Crypt/DES.php
@@ -937,7 +937,7 @@ class Crypt_DES {
             if (($length & 7) == 0) {
                 return $text;
             } else {
-                user_error("The plaintext's length ($length) is not a multiple of the block size (8)", E_USER_NOTICE);
+                $this->_handle_error("The plaintext's length ($length) is not a multiple of the block size (8)");
                 $this->padding = true;
             }
         }
@@ -1289,6 +1289,24 @@ class Crypt_DES {
         $string = substr($string, $index);
         return $substr;
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            user_error($err_msg);
+        }
+    }
 }
 
 // vim: ts=4:sw=4:et:
diff --git a/phpseclib/Crypt/RSA.php b/phpseclib/Crypt/RSA.php
index 98f6d15f..df090857 100644
--- a/phpseclib/Crypt/RSA.php
+++ b/phpseclib/Crypt/RSA.php
@@ -1746,7 +1746,7 @@ class Crypt_RSA {
     {
         $x = $x->toBytes();
         if (strlen($x) > $xLen) {
-            user_error('Integer too large', E_USER_NOTICE);
+            $this->_handle_error('Integer too large');
             return false;
         }
         return str_pad($x, $xLen, chr(0), STR_PAD_LEFT);
@@ -1908,7 +1908,7 @@ class Crypt_RSA {
     function _rsaep($m)
     {
         if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
-            user_error('Message representative out of range', E_USER_NOTICE);
+            $this->_handle_error('Message representative out of range');
             return false;
         }
         return $this->_exponentiate($m);
@@ -1926,7 +1926,7 @@ class Crypt_RSA {
     function _rsadp($c)
     {
         if ($c->compare($this->zero) < 0 || $c->compare($this->modulus) > 0) {
-            user_error('Ciphertext representative out of range', E_USER_NOTICE);
+            $this->_handle_error('Ciphertext representative out of range');
             return false;
         }
         return $this->_exponentiate($c);
@@ -1944,7 +1944,7 @@ class Crypt_RSA {
     function _rsasp1($m)
     {
         if ($m->compare($this->zero) < 0 || $m->compare($this->modulus) > 0) {
-            user_error('Message representative out of range', E_USER_NOTICE);
+            $this->_handle_error('Message representative out of range');
             return false;
         }
         return $this->_exponentiate($m);
@@ -1962,7 +1962,7 @@ class Crypt_RSA {
     function _rsavp1($s)
     {
         if ($s->compare($this->zero) < 0 || $s->compare($this->modulus) > 0) {
-            user_error('Signature representative out of range', E_USER_NOTICE);
+            $this->_handle_error('Signature representative out of range');
             return false;
         }
         return $this->_exponentiate($s);
@@ -2013,7 +2013,7 @@ class Crypt_RSA {
         // be output.
 
         if ($mLen > $this->k - 2 * $this->hLen - 2) {
-            user_error('Message too long', E_USER_NOTICE);
+            $this->_handle_error('Message too long');
             return false;
         }
 
@@ -2074,7 +2074,7 @@ class Crypt_RSA {
         // be output.
 
         if (strlen($c) != $this->k || $this->k < 2 * $this->hLen + 2) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
 
@@ -2083,7 +2083,7 @@ class Crypt_RSA {
         $c = $this->_os2ip($c);
         $m = $this->_rsadp($c);
         if ($m === false) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
         $em = $this->_i2osp($m, $this->k);
@@ -2101,12 +2101,12 @@ class Crypt_RSA {
         $lHash2 = substr($db, 0, $this->hLen);
         $m = substr($db, $this->hLen);
         if ($lHash != $lHash2) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
         $m = ltrim($m, chr(0));
         if (ord($m[0]) != 1) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
 
@@ -2131,7 +2131,7 @@ class Crypt_RSA {
         // Length checking
 
         if ($mLen > $this->k - 11) {
-            user_error('Message too long', E_USER_NOTICE);
+            $this->_handle_error('Message too long');
             return false;
         }
 
@@ -2175,7 +2175,7 @@ class Crypt_RSA {
         // Length checking
 
         if (strlen($c) != $this->k) { // or if k < 11
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
 
@@ -2185,7 +2185,7 @@ class Crypt_RSA {
         $m = $this->_rsadp($c);
 
         if ($m === false) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
         $em = $this->_i2osp($m, $this->k);
@@ -2193,7 +2193,7 @@ class Crypt_RSA {
         // EME-PKCS1-v1_5 decoding
 
         if (ord($em[0]) != 0 || ord($em[1]) > 2) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
 
@@ -2201,7 +2201,7 @@ class Crypt_RSA {
         $m = substr($em, strlen($ps) + 3);
 
         if (strlen($ps) < 8) {
-            user_error('Decryption error', E_USER_NOTICE);
+            $this->_handle_error('Decryption error');
             return false;
         }
 
@@ -2229,7 +2229,7 @@ class Crypt_RSA {
 
         $mHash = $this->hash->hash($m);
         if ($emLen < $this->hLen + $sLen + 2) {
-            user_error('Encoding error', E_USER_NOTICE);
+            $this->_handle_error('Encoding error');
             return false;
         }
 
@@ -2334,7 +2334,7 @@ class Crypt_RSA {
         // Length checking
 
         if (strlen($s) != $this->k) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
 
@@ -2345,12 +2345,12 @@ class Crypt_RSA {
         $s2 = $this->_os2ip($s);
         $m2 = $this->_rsavp1($s2);
         if ($m2 === false) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
         $em = $this->_i2osp($m2, $modBits >> 3);
         if ($em === false) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
 
@@ -2400,7 +2400,7 @@ class Crypt_RSA {
         $tLen = strlen($t);
 
         if ($emLen < $tLen + 11) {
-            user_error('Intended encoded message length too short', E_USER_NOTICE);
+            $this->_handle_error('Intended encoded message length too short');
             return false;
         }
 
@@ -2426,7 +2426,7 @@ class Crypt_RSA {
 
         $em = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
         if ($em === false) {
-            user_error('RSA modulus too short', E_USER_NOTICE);
+            $this->_handle_error('RSA modulus too short');
             return false;
         }
 
@@ -2455,7 +2455,7 @@ class Crypt_RSA {
         // Length checking
 
         if (strlen($s) != $this->k) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
 
@@ -2464,12 +2464,12 @@ class Crypt_RSA {
         $s = $this->_os2ip($s);
         $m2 = $this->_rsavp1($s);
         if ($m2 === false) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
         $em = $this->_i2osp($m2, $this->k);
         if ($em === false) {
-            user_error('Invalid signature', E_USER_NOTICE);
+            $this->_handle_error('Invalid signature');
             return false;
         }
 
@@ -2477,7 +2477,7 @@ class Crypt_RSA {
 
         $em2 = $this->_emsa_pkcs1_v1_5_encode($m, $this->k);
         if ($em2 === false) {
-            user_error('RSA modulus too short', E_USER_NOTICE);
+            $this->_handle_error('RSA modulus too short');
             return false;
         }
 
@@ -2639,4 +2639,22 @@ class Crypt_RSA {
                 return $this->_rsassa_pss_verify($message, $signature);
         }
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
\ No newline at end of file
diff --git a/phpseclib/Crypt/Rijndael.php b/phpseclib/Crypt/Rijndael.php
index e7f17a6f..71155c89 100644
--- a/phpseclib/Crypt/Rijndael.php
+++ b/phpseclib/Crypt/Rijndael.php
@@ -582,7 +582,7 @@ class Crypt_Rijndael {
      *
      * Depending on what $method is set to, setPassword()'s (optional) parameters are as follows:
      *     {@link http://en.wikipedia.org/wiki/PBKDF2 pbkdf2}:
-     *         $hash, $salt, $count
+     *         $hash, $salt, $method
      *     Set $dkLen by calling setKeyLength()
      *
      * @param String $password
@@ -601,7 +601,7 @@ class Crypt_Rijndael {
                 }
                 // WPA and WPA use the SSID as the salt
                 if (!isset($salt)) {
-                    $salt = 'phpseclib/salt';
+                    $salt = 'phpseclib';
                 }
                 // RFC2898#section-4.2 uses 1,000 iterations by default
                 // WPA and WPA2 use 4,096.
@@ -1365,7 +1365,7 @@ class Crypt_Rijndael {
             if ($length % $this->block_size == 0) {
                 return $text;
             } else {
-                user_error("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size})", E_USER_NOTICE);
+                $this->_handle_error("The plaintext's length ($length) is not a multiple of the block size ({$this->block_size})");
                 $this->padding = true;
             }
         }
@@ -1472,7 +1472,25 @@ class Crypt_Rijndael {
         $string = substr($string, $index);
         return $substr;
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            user_error($err_msg);
+        }
+    }
 }
 
 // vim: ts=4:sw=4:et:
-// vim6: fdl=1:
+// vim6: fdl=1:
\ No newline at end of file
diff --git a/phpseclib/File/ANSI.php b/phpseclib/File/ANSI.php
index 29ad949e..b601e222 100644
--- a/phpseclib/File/ANSI.php
+++ b/phpseclib/File/ANSI.php
@@ -409,7 +409,7 @@ class File_ANSI {
                                                 case 47: $back = 'white'; break;
 
                                                 default:
-                                                    user_error('Unsupported attribute: ' . $mod);
+                                                    $this->_handle_error('Unsupported attribute: ' . $mod);
                                                     $this->ansi = '';
                                                     break 2;
                                             }
@@ -537,4 +537,22 @@ class File_ANSI {
 
         return '<pre style="color: white; background: black" width="' . ($this->max_x + 1) . '">' . $scrollback . '</pre>';
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
diff --git a/phpseclib/File/ASN1.php b/phpseclib/File/ASN1.php
index 0ed044fd..dcc8da45 100644
--- a/phpseclib/File/ASN1.php
+++ b/phpseclib/File/ASN1.php
@@ -955,7 +955,7 @@ class File_ASN1 {
             case FILE_ASN1_TYPE_OBJECT_IDENTIFIER:
                 $oid = preg_match('#(?:\d+\.)+#', $source) ? $source : array_search($source, $this->oids);
                 if ($oid === false) {
-                    user_error('Invalid OID', E_USER_NOTICE);
+                    $this->_handle_error('Invalid OID');
                     return false;
                 }
                 $value = '';
@@ -1008,7 +1008,7 @@ class File_ASN1 {
                     $filters = $filters[$part];
                 }
                 if ($filters === false) {
-                    user_error('No filters defined for ' . implode('/', $loc), E_USER_NOTICE);
+                    $this->_handle_error('No filters defined for ' . implode('/', $loc));
                     return false;
                 }
                 return $this->_encode_der($source, $filters + $mapping);
@@ -1032,7 +1032,7 @@ class File_ASN1 {
                 $value = $source ? "\xFF" : "\x00";
                 break;
             default:
-                user_error('Mapping provides no type definition for ' . implode('/', $this->location), E_USER_NOTICE);
+                $this->_handle_error('Mapping provides no type definition for ' . implode('/', $this->location));
                 return false;
         }
 
@@ -1270,4 +1270,22 @@ class File_ASN1 {
         }
         return $out;
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
diff --git a/phpseclib/File/X509.php b/phpseclib/File/X509.php
index 2f0ce3c1..7e1e6b8d 100644
--- a/phpseclib/File/X509.php
+++ b/phpseclib/File/X509.php
@@ -1569,7 +1569,7 @@ class File_X509 {
                 $map = $this->_getMapping($id);
                 if (is_bool($map)) {
                     if (!$map) {
-                        user_error($id . ' is not a currently supported extension', E_USER_NOTICE);
+                        $this->_handle_error($id . ' is not a currently supported extension');
                         unset($extensions[$i]);
                     }
                 } else {
@@ -3839,4 +3839,22 @@ class File_X509 {
 
         return false;
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
diff --git a/phpseclib/Net/SFTP.php b/phpseclib/Net/SFTP.php
index fc2bf2e9..3fb149df 100644
--- a/phpseclib/Net/SFTP.php
+++ b/phpseclib/Net/SFTP.php
@@ -399,7 +399,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_VERSION) {
-            user_error('Expected SSH_FXP_VERSION', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_VERSION');
             return false;
         }
 
@@ -588,7 +588,7 @@ class Net_SFTP extends Net_SSH2 {
                 $this->_logError($response);
                 return false;
             default:
-                user_error('Expected SSH_FXP_NAME or SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_NAME or SSH_FXP_STATUS');
                 return false;
         }
 
@@ -645,7 +645,7 @@ class Net_SFTP extends Net_SSH2 {
                 $this->_logError($response);
                 return false;
             default:
-                user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS');
                 return false;
         }
 
@@ -655,7 +655,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -731,7 +731,7 @@ class Net_SFTP extends Net_SSH2 {
                 $this->_logError($response);
                 return false;
             default:
-                user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS');
                 return false;
         }
 
@@ -780,7 +780,7 @@ class Net_SFTP extends Net_SSH2 {
                     }
                     break 2;
                 default:
-                    user_error('Expected SSH_FXP_NAME or SSH_FXP_STATUS', E_USER_NOTICE);
+                    $this->_handle_error('Expected SSH_FXP_NAME or SSH_FXP_STATUS');
                     return false;
             }
         }
@@ -793,7 +793,7 @@ class Net_SFTP extends Net_SSH2 {
         //  -- http://tools.ietf.org/html/draft-ietf-secsh-filexfer-13#section-8.1.3
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -996,7 +996,7 @@ class Net_SFTP extends Net_SSH2 {
                 return false;
         }
 
-        user_error('Expected SSH_FXP_ATTRS or SSH_FXP_STATUS', E_USER_NOTICE);
+        $this->_handle_error('Expected SSH_FXP_ATTRS or SSH_FXP_STATUS');
         return false;
     }
 
@@ -1089,7 +1089,7 @@ class Net_SFTP extends Net_SSH2 {
         */
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1116,7 +1116,7 @@ class Net_SFTP extends Net_SSH2 {
                 return false;
         }
 
-        user_error('Expected SSH_FXP_ATTRS or SSH_FXP_STATUS', E_USER_NOTICE);
+        $this->_handle_error('Expected SSH_FXP_ATTRS or SSH_FXP_STATUS');
         return false;
     }
 
@@ -1249,7 +1249,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1288,7 +1288,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1365,7 +1365,7 @@ class Net_SFTP extends Net_SSH2 {
                 $this->_logError($response);
                 return false;
             default:
-                user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS');
                 return false;
         }
 
@@ -1374,7 +1374,7 @@ class Net_SFTP extends Net_SSH2 {
         // http://tools.ietf.org/html/draft-ietf-secsh-filexfer-13#section-8.2.3
         if ($mode & NET_SFTP_LOCAL_FILE) {
             if (!is_file($data)) {
-                user_error("$data is not a valid file", E_USER_NOTICE);
+                $this->_handle_error("$data is not a valid file");
                 return false;
             }
             $fp = @fopen($data, 'rb');
@@ -1425,7 +1425,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1453,7 +1453,7 @@ class Net_SFTP extends Net_SSH2 {
         while ($i--) {
             $response = $this->_get_sftp_packet();
             if ($this->packet_type != NET_SFTP_STATUS) {
-                user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_STATUS');
                 return false;
             }
 
@@ -1504,7 +1504,7 @@ class Net_SFTP extends Net_SSH2 {
                 $this->_logError($response);
                 return false;
             default:
-                user_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS', E_USER_NOTICE);
+                $this->_handle_error('Expected SSH_FXP_HANDLE or SSH_FXP_STATUS');
                 return false;
         }
 
@@ -1542,7 +1542,7 @@ class Net_SFTP extends Net_SSH2 {
                     $this->_logError($response);
                     break 2;
                 default:
-                    user_error('Expected SSH_FXP_DATA or SSH_FXP_STATUS', E_USER_NOTICE);
+                    $this->_handle_error('Expected SSH_FXP_DATA or SSH_FXP_STATUS');
                     if ($local_file !== false) {
                         fclose($fp);
                     }
@@ -1560,7 +1560,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1604,7 +1604,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
@@ -1723,7 +1723,7 @@ class Net_SFTP extends Net_SSH2 {
 
         $response = $this->_get_sftp_packet();
         if ($this->packet_type != NET_SFTP_STATUS) {
-            user_error('Expected SSH_FXP_STATUS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_FXP_STATUS');
             return false;
         }
 
diff --git a/phpseclib/Net/SSH1.php b/phpseclib/Net/SSH1.php
index 67e09652..b6a5e652 100644
--- a/phpseclib/Net/SSH1.php
+++ b/phpseclib/Net/SSH1.php
@@ -467,7 +467,7 @@ class Net_SSH1 {
 
         $this->fsock = @fsockopen($host, $port, $errno, $errstr, $timeout);
         if (!$this->fsock) {
-            user_error(rtrim("Cannot connect to $host. Error $errno. $errstr"), E_USER_NOTICE);
+            $this->_handle_error(rtrim("Cannot connect to $host. Error $errno. $errstr"));
             return;
         }
 
@@ -484,11 +484,11 @@ class Net_SSH1 {
         }
 
         if (!preg_match('#SSH-([0-9\.]+)-(.+)#', $init_line, $parts)) {
-            user_error('Can only connect to SSH servers', E_USER_NOTICE);
+            $this->_handle_error('Can only connect to SSH servers');
             return;
         }
         if ($parts[1][0] != 1) {
-            user_error("Cannot connect to SSH $parts[1] servers", E_USER_NOTICE);
+            $this->_handle_error("Cannot connect to SSH $parts[1] servers");
             return;
         }
 
@@ -496,7 +496,7 @@ class Net_SSH1 {
 
         $response = $this->_get_binary_packet();
         if ($response[NET_SSH1_RESPONSE_TYPE] != NET_SSH1_SMSG_PUBLIC_KEY) {
-            user_error('Expected SSH_SMSG_PUBLIC_KEY', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_SMSG_PUBLIC_KEY');
             return;
         }
 
@@ -584,7 +584,7 @@ class Net_SSH1 {
         $data = pack('C2a*na*N', NET_SSH1_CMSG_SESSION_KEY, $cipher, $anti_spoofing_cookie, 8 * strlen($double_encrypted_session_key), $double_encrypted_session_key, 0);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_SESSION_KEY', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_SESSION_KEY');
             return;
         }
 
@@ -614,7 +614,7 @@ class Net_SSH1 {
         $response = $this->_get_binary_packet();
 
         if ($response[NET_SSH1_RESPONSE_TYPE] != NET_SSH1_SMSG_SUCCESS) {
-            user_error('Expected SSH_SMSG_SUCCESS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_SMSG_SUCCESS');
             return;
         }
 
@@ -638,7 +638,7 @@ class Net_SSH1 {
         $data = pack('CNa*', NET_SSH1_CMSG_USER, strlen($username), $username);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_USER', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_USER');
             return false;
         }
 
@@ -648,14 +648,14 @@ class Net_SSH1 {
             $this->bitmap |= NET_SSH1_MASK_LOGIN;
             return true;
         } else if ($response[NET_SSH1_RESPONSE_TYPE] != NET_SSH1_SMSG_FAILURE) {
-            user_error('Expected SSH_SMSG_SUCCESS or SSH_SMSG_FAILURE', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_SMSG_SUCCESS or SSH_SMSG_FAILURE');
             return false;
         }
 
         $data = pack('CNa*', NET_SSH1_CMSG_AUTH_PASSWORD, strlen($password), $password);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_AUTH_PASSWORD', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_AUTH_PASSWORD');
             return false;
         }
 
@@ -673,7 +673,7 @@ class Net_SSH1 {
         } else if ($response[NET_SSH1_RESPONSE_TYPE] == NET_SSH1_SMSG_FAILURE) {
             return false;
         } else {
-            user_error('Expected SSH_SMSG_SUCCESS or SSH_SMSG_FAILURE', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_SMSG_SUCCESS or SSH_SMSG_FAILURE');
             return false;
         }
     }
@@ -701,14 +701,14 @@ class Net_SSH1 {
     function exec($cmd, $block = true)
     {
         if (!($this->bitmap & NET_SSH1_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         $data = pack('CNa*', NET_SSH1_CMSG_EXEC_CMD, strlen($cmd), $cmd);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_EXEC_CMD', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_EXEC_CMD');
             return false;
         }
 
@@ -753,21 +753,21 @@ class Net_SSH1 {
         $data = pack('CNa*N4C', NET_SSH1_CMSG_REQUEST_PTY, strlen('vt100'), 'vt100', 24, 80, 0, 0, NET_SSH1_TTY_OP_END);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_REQUEST_PTY', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_REQUEST_PTY');
             return false;
         }
 
         $response = $this->_get_binary_packet();
 
         if ($response[NET_SSH1_RESPONSE_TYPE] != NET_SSH1_SMSG_SUCCESS) {
-            user_error('Expected SSH_SMSG_SUCCESS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_SMSG_SUCCESS');
             return false;
         }
 
         $data = pack('C', NET_SSH1_CMSG_EXEC_SHELL);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_EXEC_SHELL', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_EXEC_SHELL');
             return false;
         }
 
@@ -806,12 +806,12 @@ class Net_SSH1 {
     function read($expect, $mode = NET_SSH1_READ_SIMPLE)
     {
         if (!($this->bitmap & NET_SSH1_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         if (!($this->bitmap & NET_SSH1_MASK_SHELL) && !$this->_initShell()) {
-            user_error('Unable to initiate an interactive shell session', E_USER_NOTICE);
+            $this->_handle_error('Unable to initiate an interactive shell session');
             return false;
         }
 
@@ -841,19 +841,19 @@ class Net_SSH1 {
     function interactiveWrite($cmd)
     {
         if (!($this->bitmap & NET_SSH1_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         if (!($this->bitmap & NET_SSH1_MASK_SHELL) && !$this->_initShell()) {
-            user_error('Unable to initiate an interactive shell session', E_USER_NOTICE);
+            $this->_handle_error('Unable to initiate an interactive shell session');
             return false;
         }
 
         $data = pack('CNa*', NET_SSH1_CMSG_STDIN_DATA, strlen($cmd), $cmd);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Error sending SSH_CMSG_STDIN', E_USER_NOTICE);
+            $this->_handle_error('Error sending SSH_CMSG_STDIN');
             return false;
         }
 
@@ -876,12 +876,12 @@ class Net_SSH1 {
     function interactiveRead()
     {
         if (!($this->bitmap & NET_SSH1_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         if (!($this->bitmap & NET_SSH1_MASK_SHELL) && !$this->_initShell()) {
-            user_error('Unable to initiate an interactive shell session', E_USER_NOTICE);
+            $this->_handle_error('Unable to initiate an interactive shell session');
             return false;
         }
 
@@ -960,7 +960,7 @@ class Net_SSH1 {
     function _get_binary_packet()
     {
         if (feof($this->fsock)) {
-            //user_error('connection closed prematurely', E_USER_NOTICE);
+            //$this->_handle_error('connection closed prematurely');
             return false;
         }
 
@@ -984,7 +984,7 @@ class Net_SSH1 {
         $temp = unpack('Ncrc', substr($raw, -4));
 
         //if ( $temp['crc'] != $this->_crc($padding . $type . $data) ) {
-        //    user_error('Bad CRC in packet from server', E_USER_NOTICE);
+        //    $this->_handle_error('Bad CRC in packet from server');
         //    return false;
         //}
 
@@ -1017,7 +1017,7 @@ class Net_SSH1 {
      */
     function _send_binary_packet($data) {
         if (feof($this->fsock)) {
-            //user_error('connection closed prematurely', E_USER_NOTICE);
+            //$this->_handle_error('connection closed prematurely');
             return false;
         }
 
@@ -1418,4 +1418,22 @@ class Net_SSH1 {
     {
         return rtrim($this->server_identification);
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
diff --git a/phpseclib/Net/SSH2.php b/phpseclib/Net/SSH2.php
index 29a8f0f4..7ca86f43 100644
--- a/phpseclib/Net/SSH2.php
+++ b/phpseclib/Net/SSH2.php
@@ -793,7 +793,7 @@ class Net_SSH2 {
         $start = strtok(microtime(), ' ') + strtok(''); // http://php.net/microtime#61838
         $this->fsock = @fsockopen($host, $port, $errno, $errstr, $timeout);
         if (!$this->fsock) {
-            user_error(rtrim("Cannot connect to $host. Error $errno. $errstr"), E_USER_NOTICE);
+            $this->_handle_error(rtrim("Cannot connect to $host. Error $errno. $errstr"));
             return;
         }
         $elapsed = strtok(microtime(), ' ') + strtok('') - $start;
@@ -801,7 +801,7 @@ class Net_SSH2 {
         $timeout-= $elapsed;
 
         if ($timeout <= 0) {
-            user_error(rtrim("Cannot connect to $host. Timeout error"), E_USER_NOTICE);
+            $this->_handle_error(rtrim("Cannot connect to $host. Timeout error"));
             return;
         }
 
@@ -814,7 +814,7 @@ class Net_SSH2 {
         // on windows this returns a "Warning: Invalid CRT parameters detected" error
         // the !count() is done as a workaround for <https://bugs.php.net/42682>
         if (!@stream_select($read, $write, $except, $sec, $usec) && !count($read)) {
-            user_error(rtrim("Cannot connect to $host. Banner timeout"), E_USER_NOTICE);
+            $this->_handle_error(rtrim("Cannot connect to $host. Banner timeout"));
             return;
         }
 
@@ -836,7 +836,7 @@ class Net_SSH2 {
         }
 
         if (feof($this->fsock)) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -870,7 +870,7 @@ class Net_SSH2 {
         }
 
         if ($matches[1] != '1.99' && $matches[1] != '2.0') {
-            user_error("Cannot connect to SSH $matches[1] servers", E_USER_NOTICE);
+            $this->_handle_error("Cannot connect to SSH $matches[1] servers");
             return;
         }
 
@@ -878,12 +878,12 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return;
         }
 
         if (ord($response[0]) != NET_SSH2_MSG_KEXINIT) {
-            user_error('Expected SSH_MSG_KEXINIT', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_MSG_KEXINIT');
             return;
         }
 
@@ -1028,7 +1028,7 @@ class Net_SSH2 {
         // we need to decide upon the symmetric encryption algorithms before we do the diffie-hellman key exchange
         for ($i = 0; $i < count($encryption_algorithms) && !in_array($encryption_algorithms[$i], $this->encryption_algorithms_server_to_client); $i++);
         if ($i == count($encryption_algorithms)) {
-            user_error('No compatible server to client encryption algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible server to client encryption algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1065,7 +1065,7 @@ class Net_SSH2 {
 
         for ($i = 0; $i < count($encryption_algorithms) && !in_array($encryption_algorithms[$i], $this->encryption_algorithms_client_to_server); $i++);
         if ($i == count($encryption_algorithms)) {
-            user_error('No compatible client to server encryption algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible client to server encryption algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1103,7 +1103,7 @@ class Net_SSH2 {
         // through diffie-hellman key exchange a symmetric key is obtained
         for ($i = 0; $i < count($kex_algorithms) && !in_array($kex_algorithms[$i], $this->kex_algorithms); $i++);
         if ($i == count($kex_algorithms)) {
-            user_error('No compatible key exchange algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible key exchange algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1156,19 +1156,19 @@ class Net_SSH2 {
         $data = pack('CNa*', NET_SSH2_MSG_KEXDH_INIT, strlen($eBytes), $eBytes);
 
         if (!$this->_send_binary_packet($data)) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
         extract(unpack('Ctype', $this->_string_shift($response, 1)));
 
         if ($type != NET_SSH2_MSG_KEXDH_REPLY) {
-            user_error('Expected SSH_MSG_KEXDH_REPLY', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_MSG_KEXDH_REPLY');
             return false;
         }
 
@@ -1206,12 +1206,12 @@ class Net_SSH2 {
 
         for ($i = 0; $i < count($server_host_key_algorithms) && !in_array($server_host_key_algorithms[$i], $this->server_host_key_algorithms); $i++);
         if ($i == count($server_host_key_algorithms)) {
-            user_error('No compatible server host key algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible server host key algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
         if ($public_key_format != $server_host_key_algorithms[$i] || $this->signature_format != $server_host_key_algorithms[$i]) {
-            user_error('Sever Host Key Algorithm Mismatch', E_USER_NOTICE);
+            $this->_handle_error('Sever Host Key Algorithm Mismatch');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1226,14 +1226,14 @@ class Net_SSH2 {
         $response = $this->_get_binary_packet();
 
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
         extract(unpack('Ctype', $this->_string_shift($response, 1)));
 
         if ($type != NET_SSH2_MSG_NEWKEYS) {
-            user_error('Expected SSH_MSG_NEWKEYS', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_MSG_NEWKEYS');
             return false;
         }
 
@@ -1347,7 +1347,7 @@ class Net_SSH2 {
 
         for ($i = 0; $i < count($mac_algorithms) && !in_array($mac_algorithms[$i], $this->mac_algorithms_client_to_server); $i++);
         if ($i == count($mac_algorithms)) {
-            user_error('No compatible client to server message authentication algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible client to server message authentication algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1372,7 +1372,7 @@ class Net_SSH2 {
 
         for ($i = 0; $i < count($mac_algorithms) && !in_array($mac_algorithms[$i], $this->mac_algorithms_server_to_client); $i++);
         if ($i == count($mac_algorithms)) {
-            user_error('No compatible server to client message authentication algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible server to client message authentication algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
 
@@ -1414,14 +1414,14 @@ class Net_SSH2 {
 
         for ($i = 0; $i < count($compression_algorithms) && !in_array($compression_algorithms[$i], $this->compression_algorithms_server_to_client); $i++);
         if ($i == count($compression_algorithms)) {
-            user_error('No compatible server to client compression algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible server to client compression algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
         $this->decompress = $compression_algorithms[$i] == 'zlib';
 
         for ($i = 0; $i < count($compression_algorithms) && !in_array($compression_algorithms[$i], $this->compression_algorithms_client_to_server); $i++);
         if ($i == count($compression_algorithms)) {
-            user_error('No compatible client to server compression algorithms found', E_USER_NOTICE);
+            $this->_handle_error('No compatible client to server compression algorithms found');
             return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
         }
         $this->compress = $compression_algorithms[$i] == 'zlib';
@@ -1457,14 +1457,14 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
         extract(unpack('Ctype', $this->_string_shift($response, 1)));
 
         if ($type != NET_SSH2_MSG_SERVICE_ACCEPT) {
-            user_error('Expected SSH_MSG_SERVICE_ACCEPT', E_USER_NOTICE);
+            $this->_handle_error('Expected SSH_MSG_SERVICE_ACCEPT');
             return false;
         }
 
@@ -1485,7 +1485,7 @@ class Net_SSH2 {
 
             $response = $this->_get_binary_packet();
             if ($response === false) {
-                user_error('Connection closed by server', E_USER_NOTICE);
+                $this->_handle_error('Connection closed by server');
                 return false;
             }
 
@@ -1521,7 +1521,7 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -1593,7 +1593,7 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -1706,7 +1706,7 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -1741,7 +1741,7 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -1894,7 +1894,7 @@ class Net_SSH2 {
 
         $response = $this->_get_binary_packet();
         if ($response === false) {
-            user_error('Connection closed by server', E_USER_NOTICE);
+            $this->_handle_error('Connection closed by server');
             return false;
         }
 
@@ -1905,7 +1905,7 @@ class Net_SSH2 {
                 break;
             case NET_SSH2_MSG_CHANNEL_FAILURE:
             default:
-                user_error('Unable to request pseudo-terminal', E_USER_NOTICE);
+                $this->_handle_error('Unable to request pseudo-terminal');
                 return $this->_disconnect(NET_SSH2_DISCONNECT_BY_APPLICATION);
         }
 
@@ -1946,12 +1946,12 @@ class Net_SSH2 {
         $this->curTimeout = $this->timeout;
 
         if (!($this->bitmap & NET_SSH2_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         if (!($this->bitmap & NET_SSH2_MASK_SHELL) && !$this->_initShell()) {
-            user_error('Unable to initiate an interactive shell session', E_USER_NOTICE);
+            $this->_handle_error('Unable to initiate an interactive shell session');
             return false;
         }
 
@@ -1985,12 +1985,12 @@ class Net_SSH2 {
     function write($cmd)
     {
         if (!($this->bitmap & NET_SSH2_MASK_LOGIN)) {
-            user_error('Operation disallowed prior to login()', E_USER_NOTICE);
+            $this->_handle_error('Operation disallowed prior to login()');
             return false;
         }
 
         if (!($this->bitmap & NET_SSH2_MASK_SHELL) && !$this->_initShell()) {
-            user_error('Unable to initiate an interactive shell session', E_USER_NOTICE);
+            $this->_handle_error('Unable to initiate an interactive shell session');
             return false;
         }
 
@@ -2035,7 +2035,7 @@ class Net_SSH2 {
     function _get_binary_packet()
     {
         if (!is_resource($this->fsock) || feof($this->fsock)) {
-            user_error('Connection closed prematurely', E_USER_NOTICE);
+            $this->_handle_error('Connection closed prematurely');
             $this->bitmask = 0;
             return false;
         }
@@ -2052,7 +2052,7 @@ class Net_SSH2 {
             $raw = $this->decrypt->decrypt($raw);
         }
         if ($raw === false) {
-            user_error('Unable to decrypt content', E_USER_NOTICE);
+            $this->_handle_error('Unable to decrypt content');
             return false;
         }
 
@@ -2076,7 +2076,7 @@ class Net_SSH2 {
         if ($this->hmac_check !== false) {
             $hmac = fread($this->fsock, $this->hmac_size);
             if ($hmac != $this->hmac_check->hash(pack('NNCa*', $this->get_seq_no, $packet_length, $padding_length, $payload . $padding))) {
-                user_error('Invalid HMAC', E_USER_NOTICE);
+                $this->_handle_error('Invalid HMAC');
                 return false;
             }
         }
@@ -2243,7 +2243,7 @@ class Net_SSH2 {
 
             $response = $this->_get_binary_packet();
             if ($response === false) {
-                user_error('Connection closed by server', E_USER_NOTICE);
+                $this->_handle_error('Connection closed by server');
                 return false;
             }
 
@@ -2265,7 +2265,7 @@ class Net_SSH2 {
                             return $client_channel == $channel ? true : $this->_get_channel_packet($client_channel, $skip_extended);
                         //case NET_SSH2_MSG_CHANNEL_OPEN_FAILURE:
                         default:
-                            user_error('Unable to open channel', E_USER_NOTICE);
+                            $this->_handle_error('Unable to open channel');
                             return $this->_disconnect(NET_SSH2_DISCONNECT_BY_APPLICATION);
                     }
                     break;
@@ -2275,7 +2275,7 @@ class Net_SSH2 {
                             return true;
                         //case NET_SSH2_MSG_CHANNEL_FAILURE:
                         default:
-                            user_error('Unable to request pseudo-terminal', E_USER_NOTICE);
+                            $this->_handle_error('Unable to request pseudo-terminal');
                             return $this->_disconnect(NET_SSH2_DISCONNECT_BY_APPLICATION);
                     }
                 case NET_SSH2_MSG_CHANNEL_CLOSE:
@@ -2364,7 +2364,7 @@ class Net_SSH2 {
                 case NET_SSH2_MSG_CHANNEL_EOF:
                     break;
                 default:
-                    user_error('Error reading channel data', E_USER_NOTICE);
+                    $this->_handle_error('Error reading channel data');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_BY_APPLICATION);
             }
         }
@@ -2383,7 +2383,7 @@ class Net_SSH2 {
     function _send_binary_packet($data)
     {
         if (!is_resource($this->fsock) || feof($this->fsock)) {
-            user_error('Connection closed prematurely', E_USER_NOTICE);
+            $this->_handle_error('Connection closed prematurely');
             $this->bitmask = 0;
             return false;
         }
@@ -2894,7 +2894,7 @@ class Net_SSH2 {
                    padding, unsigned, and in network byte order). */
                 $temp = unpack('Nlength', $this->_string_shift($signature, 4));
                 if ($temp['length'] != 40) {
-                    user_error('Invalid signature', E_USER_NOTICE);
+                    $this->_handle_error('Invalid signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
                 }
 
@@ -2902,7 +2902,7 @@ class Net_SSH2 {
                 $s = new Math_BigInteger($this->_string_shift($signature, 20), 256);
 
                 if ($r->compare($q) >= 0 || $s->compare($q) >= 0) {
-                    user_error('Invalid signature', E_USER_NOTICE);
+                    $this->_handle_error('Invalid signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
                 }
 
@@ -2922,7 +2922,7 @@ class Net_SSH2 {
                 list(, $v) = $v->divide($q);
 
                 if (!$v->equals($r)) {
-                    user_error('Bad server signature', E_USER_NOTICE);
+                    $this->_handle_error('Bad server signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
                 }
 
@@ -2947,7 +2947,7 @@ class Net_SSH2 {
                 $rsa->setSignatureMode(CRYPT_RSA_SIGNATURE_PKCS1);
                 $rsa->loadKey(array('e' => $e, 'n' => $n), CRYPT_RSA_PUBLIC_FORMAT_RAW);
                 if (!$rsa->verify($this->exchange_hash, $signature)) {
-                    user_error('Bad server signature', E_USER_NOTICE);
+                    $this->_handle_error('Bad server signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
                 }
                 */
@@ -2962,7 +2962,7 @@ class Net_SSH2 {
                 // also, see SSHRSA.c (rsa2_verifysig) in PuTTy's source.
 
                 if ($s->compare(new Math_BigInteger()) < 0 || $s->compare($n->subtract(new Math_BigInteger(1))) > 0) {
-                    user_error('Invalid signature', E_USER_NOTICE);
+                    $this->_handle_error('Invalid signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_KEY_EXCHANGE_FAILED);
                 }
 
@@ -2973,15 +2973,33 @@ class Net_SSH2 {
                 $h = chr(0x01) . str_repeat(chr(0xFF), $nLength - 3 - strlen($h)) . $h;
 
                 if ($s != $h) {
-                    user_error('Bad server signature', E_USER_NOTICE);
+                    $this->_handle_error('Bad server signature');
                     return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
                 }
                 break;
             default:
-                user_error('Unsupported signature format', E_USER_NOTICE);
+                $this->_handle_error('Unsupported signature format');
                 return $this->_disconnect(NET_SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE);
         }
 
         return $this->signature_format . ' ' . base64_encode($this->server_public_host_key);
     }
+
+    /**
+     * Error Handler
+     *
+     * Throws exceptions if PHPSECLIB_USE_EXCEPTIONS is defined.
+     * Unless PHPSECLIB_EXCEPTION_CLASS is set it'll throw generic Exceptions.
+     *
+     * @param String $string
+     * @access private
+     */
+    function _handle_error($err_msg) {
+        if (defined('PHPSECLIB_USE_EXCEPTIONS') && version_compare(PHP_VERSION, '5.1.0', '>=')) {
+            $class = defined('PHPSECLIB_EXCEPTION_CLASS') && class_exists(PHPSECLIB_EXCEPTION_CLASS) ? PHPSECLIB_EXCEPTION_CLASS : 'Exception';
+            throw(new $class($err_msg));
+        } else {
+            $this->_handle_error($err_msg);
+        }
+    }
 }
\ No newline at end of file