From cd40f978f769c6029fdb5839ca0e2f71485e5eae Mon Sep 17 00:00:00 2001 From: Jim Wigginton Date: Sun, 7 Jun 2009 00:51:45 +0000 Subject: - added sftp support git-svn-id: file:///svn/phpbb/trunk@9553 89ea8834-ac86-4346-8a33-228a782c2dd0 --- phpBB/includes/sftp/des.php | 1428 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1428 insertions(+) create mode 100644 phpBB/includes/sftp/des.php (limited to 'phpBB/includes/sftp/des.php') diff --git a/phpBB/includes/sftp/des.php b/phpBB/includes/sftp/des.php new file mode 100644 index 0000000000..278de64a01 --- /dev/null +++ b/phpBB/includes/sftp/des.php @@ -0,0 +1,1428 @@ + +* Copyright 2009+ phpBB +* +* @package sftp +* @author TerraFrost +*/ + +/**#@+ + * @access private + * @see des::_prepare_key() + * @see des::_process_block() + */ +/** + * Contains array_reverse($keys[CRYPT_DES_DECRYPT]) + */ +define('CRYPT_DES_ENCRYPT', 0); +/** + * Contains array_reverse($keys[CRYPT_DES_ENCRYPT]) + */ +define('CRYPT_DES_DECRYPT', 1); +/**#@-*/ + +/**#@+ + * @access public + * @see des::encrypt() + * @see des::decrypt() + */ +/** + * Encrypt / decrypt using the Electronic Code Book mode. + * + * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29 + */ +define('CRYPT_DES_MODE_ECB', 1); +/** + * Encrypt / decrypt using the Code Book Chaining mode. + * + * @link http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Cipher-block_chaining_.28CBC.29 + */ +define('CRYPT_DES_MODE_CBC', 2); +/**#@-*/ + +/** + * Encrypt / decrypt using inner chaining + * + * Inner chaining is used by SSH-1 and is generally considered to be less secure then outer chaining (CRYPT_DES_MODE_CBC3). + */ +define('CRYPT_DES_MODE_3CBC', 3); + +/** + * Encrypt / decrypt using outer chaining + * + * Outer chaining is used by SSH-2 and when the mode is set to CRYPT_DES_MODE_CBC. + */ +define('CRYPT_DES_MODE_CBC3', CRYPT_DES_MODE_CBC); + +/**#@+ + * @access private + * @see des::__construct() + */ +/** + * Toggles the internal implementation + */ +define('CRYPT_DES_MODE_INTERNAL', 1); +/** + * Toggles the mcrypt implementation + */ +define('CRYPT_DES_MODE_MCRYPT', 2); +/**#@-*/ + +/** + * Pure-PHP implementation of DES. + * + * @author Jim Wigginton + * @version 0.1.0 + * @access public + * @package des + */ +class des +{ + /** + * The Key Schedule + * + * @see des::setKey() + * @var Array + * @access private + */ + var $keys = "\0\0\0\0\0\0\0\0"; + + /** + * The Encryption Mode + * + * @see des::des() + * @var Integer + * @access private + */ + var $mode; + + /** + * Continuous Buffer status + * + * @see des::enableContinuousBuffer() + * @var Boolean + * @access private + */ + var $continuousBuffer = false; + + /** + * Padding status + * + * @see des::enablePadding() + * @var Boolean + * @access private + */ + var $padding = true; + + /** + * The Initialization Vector + * + * @see des::setIV() + * @var String + * @access private + */ + var $iv = "\0\0\0\0\0\0\0\0"; + + /** + * A "sliding" Initialization Vector + * + * @see des::enableContinuousBuffer() + * @var String + * @access private + */ + var $encryptIV = "\0\0\0\0\0\0\0\0"; + + /** + * A "sliding" Initialization Vector + * + * @see des::enableContinuousBuffer() + * @var String + * @access private + */ + var $decryptIV = "\0\0\0\0\0\0\0\0"; + + /** + * MCrypt parameters + * + * @see des::setMCrypt() + * @var Array + * @access private + */ + var $mcrypt = array('', ''); + + /** + * Default Constructor. + * + * Determines whether or not the mcrypt extension should be used. $mode should only, at present, be + * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC. If not explictly set, CRYPT_DES_MODE_CBC will be used. + * + * @param optional Integer $mode + * @return des + * @access public + */ + function __construct($mode = CRYPT_MODE_DES_CBC) + { + if ( !defined('CRYPT_DES_MODE') ) + { + switch (true) + { + case extension_loaded('mcrypt'): + // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')), + // but since that can be changed after the object has been created, there doesn't seem to be + // a lot of point... + define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT); + break; + default: + define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL); + } + } + + switch ( CRYPT_DES_MODE ) + { + case CRYPT_DES_MODE_MCRYPT: + switch ($mode) + { + case CRYPT_DES_MODE_ECB: + $this->mode = MCRYPT_MODE_ECB; + break; + case CRYPT_DES_MODE_CBC: + default: + $this->mode = MCRYPT_MODE_CBC; + } + + break; + default: + switch ($mode) + { + case CRYPT_DES_MODE_ECB: + case CRYPT_DES_MODE_CBC: + $this->mode = $mode; + break; + default: + $this->mode = CRYPT_DES_MODE_CBC; + } + } + } + + /** + * Sets the key. + * + * Keys can be of any length. DES, itself, uses 64-bit keys (eg. strlen($key) == 8), however, we + * only use the first eight, if $key has more then eight characters in it, and pad $key with the + * null byte if it is less then eight characters long. + * + * DES also requires that every eighth bit be a parity bit, however, we'll ignore that. + * + * If the key is not explicitly set, it'll be assumed to be all zero's. + * + * @access public + * @param String $key + */ + function set_key($key) + { + $this->keys = ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) ? substr($key, 0, 8) : $this->_prepare_key($key); + } + + /** + * Sets the initialization vector. (optional) + * + * SetIV is not required when CRYPT_DES_MODE_ECB is being used. If not explictly set, it'll be assumed + * to be all zero's. + * + * @access public + * @param String $iv + */ + function set_iv($iv) + { + $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0));; + } + + /** + * Sets MCrypt parameters. (optional) + * + * If MCrypt is being used, empty strings will be used, unless otherwise specified. + * + * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open + * @access public + * @param optional Integer $algorithm_directory + * @param optional Integer $mode_directory + */ + function set_mcrypt($algorithm_directory = '', $mode_directory = '') + { + $this->mcrypt = array($algorithm_directory, $mode_directory); + } + + /** + * Encrypts a message. + * + * $plaintext will be padded with up to 8 additional bytes. Other DES implementations may or may not pad in the + * same manner. Other common approaches to padding and the reasons why it's necessary are discussed in the following + * URL: + * + * {@link http://www.di-mgt.com.au/cryptopad.html http://www.di-mgt.com.au/cryptopad.html} + * + * An alternative to padding is to, separately, send the length of the file. This is what SSH, in fact, does. + * strlen($plaintext) will still need to be a multiple of 8, however, arbitrary values can be added to make it that + * length. + * + * @see des::decrypt() + * @access public + * @param String $plaintext + */ + function encrypt($plaintext) + { + $plaintext = $this->_pad($plaintext); + + if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) + { + $td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]); + mcrypt_generic_init($td, $this->keys, $this->encryptIV); + + $ciphertext = mcrypt_generic($td, $plaintext); + + mcrypt_generic_deinit($td); + mcrypt_module_close($td); + + if ($this->continuousBuffer) + { + $this->encryptIV = substr($ciphertext, -8); + } + + return $ciphertext; + } + + if (!is_array($this->keys)) + { + $this->keys = $this->_prepare_key("\0\0\0\0\0\0\0\0"); + } + + $ciphertext = ''; + switch ($this->mode) + { + case CRYPT_DES_MODE_ECB: + for ($i = 0; $i < strlen($plaintext); $i+=8) + { + $ciphertext.= $this->_process_block(substr($plaintext, $i, 8), CRYPT_DES_ENCRYPT); + } + break; + case CRYPT_DES_MODE_CBC: + $xor = $this->encryptIV; + for ($i = 0; $i < strlen($plaintext); $i+=8) + { + $block = substr($plaintext, $i, 8); + $block = $this->_process_block($block ^ $xor, CRYPT_DES_ENCRYPT); + $xor = $block; + $ciphertext.= $block; + } + if ($this->continuousBuffer) + { + $this->encryptIV = $xor; + } + } + + return $ciphertext; + } + + /** + * Decrypts a message. + * + * If strlen($ciphertext) is not a multiple of 8, null bytes will be added to the end of the string until it is. + * + * @see des::encrypt() + * @access public + * @param String $ciphertext + */ + function decrypt($ciphertext) + { + // we pad with chr(0) since that's what mcrypt_generic does. to quote from http://php.net/function.mcrypt-generic : + // "The data is padded with "\0" to make sure the length of the data is n * blocksize." + $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0)); + + if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) + { + $td = mcrypt_module_open(MCRYPT_DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]); + mcrypt_generic_init($td, $this->keys, $this->decryptIV); + + $plaintext = mdecrypt_generic($td, $ciphertext); + + mcrypt_generic_deinit($td); + mcrypt_module_close($td); + + if ($this->continuousBuffer) + { + $this->decryptIV = substr($ciphertext, -8); + } + + return $this->_unpad($plaintext); + } + + if (!is_array($this->keys)) + { + $this->keys = $this->_prepare_key("\0\0\0\0\0\0\0\0"); + } + + $plaintext = ''; + switch ($this->mode) + { + case CRYPT_DES_MODE_ECB: + for ($i = 0; $i < strlen($ciphertext); $i+=8) + { + $plaintext.= $this->_process_block(substr($ciphertext, $i, 8), CRYPT_DES_DECRYPT); + } + break; + case CRYPT_DES_MODE_CBC: + $xor = $this->decryptIV; + for ($i = 0; $i < strlen($ciphertext); $i+=8) + { + $block = substr($ciphertext, $i, 8); + $plaintext.= $this->_process_block($block, CRYPT_DES_DECRYPT) ^ $xor; + $xor = $block; + } + if ($this->continuousBuffer) + { + $this->decryptIV = $xor; + } + } + + return $this->_unpad($plaintext); + } + + /** + * Treat consecutive "packets" as if they are a continuous buffer. + * + * Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets + * will yield different outputs: + * + * + * echo $des->encrypt(substr($plaintext, 0, 8)); + * echo $des->encrypt(substr($plaintext, 8, 8)); + * + * + * echo $des->encrypt($plaintext); + * + * + * The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates + * another, as demonstrated with the following: + * + * + * $des->encrypt(substr($plaintext, 0, 8)); + * echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); + * + * + * echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); + * + * + * With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different + * outputs. The reason is due to the fact that the initialization vector's change after every encryption / + * decryption round when the continuous buffer is enabled. When it's disabled, they remain constant. + * + * Put another way, when the continuous buffer is enabled, the state of the des() object changes after each + * encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that + * continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them), + * however, they are also less intuitive and more likely to cause you problems. + * + * @see des::disableContinuousBuffer() + * @access public + */ + function enable_continuous_buffer() + { + $this->continuousBuffer = true; + } + + /** + * Treat consecutive packets as if they are a discontinuous buffer. + * + * The default behavior. + * + * @see des::enableContinuousBuffer() + * @access public + */ + function disable_continuous_buffer() + { + $this->continuousBuffer = false; + $this->encryptIV = $this->iv; + $this->decryptIV = $this->iv; + } + + /** + * Pad "packets". + * + * DES works by encrypting eight bytes at a time. If you ever need to encrypt or decrypt something that's not + * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight. + * + * Padding is enabled by default. Sometimes, however, it is undesirable to pad strings. Such is the case in SSH1, + * where "packets" are padded with random bytes before being encrypted. Unpad these packets and you risk stripping + * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is + * transmitted separately) + * + * @see des::disablePadding() + * @access public + */ + function enable_padding() + { + $this->padding = true; + } + + /** + * Do not pad packets. + * + * @see des::enablePadding() + * @access public + */ + function disable_padding() + { + $this->padding = false; + } + + /** + * Pads a string + * + * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8). + * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7) + * + * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless + * and padding will, hence forth, be enabled. + * + * @see des::_unpad() + * @access private + */ + function _pad($text) + { + $length = strlen($text); + + if (!$this->padding) + { + if (($length & 7) == 0) + { + return $text; + } + else + { + $this->padding = true; + } + } + + $pad = 8 - ($length & 7); + return str_pad($text, $length + $pad, chr($pad)); + } + + /** + * Unpads a string + * + * If padding is enabled and the reported padding length exceeds the block size, padding will be, hence forth, disabled. + * + * @see des::_pad() + * @access private + */ + function _unpad($text) + { + if (!$this->padding) + { + return $text; + } + + $length = ord($text[strlen($text) - 1]); + + if ($length > 8) + { + $this->padding = false; + return $text; + } + + return substr($text, 0, -$length); + } + + /** + * Encrypts or decrypts a 64-bit block + * + * $mode should be either CRYPT_DES_ENCRYPT or CRYPT_DES_DECRYPT. See + * {@link http://en.wikipedia.org/wiki/Image:Feistel.png Feistel.png} to get a general + * idea of what this function does. + * + * @access private + * @param String $block + * @param Integer $mode + * @return String + */ + function _process_block($block, $mode) + { + // s-boxes. in the official DES docs, they're described as being matrices that + // one accesses by using the first and last bits to determine the row and the + // middle four bits to determine the column. in this implementation, they've + // been converted to vectors + static $sbox = array( + array( + 14, 0, 4, 15, 13, 7, 1, 4, 2, 14, 15, 2, 11, 13, 8, 1, + 3, 10 ,10, 6, 6, 12, 12, 11, 5, 9, 9, 5, 0, 3, 7, 8, + 4, 15, 1, 12, 14, 8, 8, 2, 13, 4, 6, 9, 2, 1, 11, 7, + 15, 5, 12, 11, 9, 3, 7, 14, 3, 10, 10, 0, 5, 6, 0, 13 + ), + array( + 15, 3, 1, 13, 8, 4, 14, 7, 6, 15, 11, 2, 3, 8, 4, 14, + 9, 12, 7, 0, 2, 1, 13, 10, 12, 6, 0, 9, 5, 11, 10, 5, + 0, 13, 14, 8, 7, 10, 11, 1, 10, 3, 4, 15, 13, 4, 1, 2, + 5, 11, 8, 6, 12, 7, 6, 12, 9, 0, 3, 5, 2, 14, 15, 9 + ), + array( + 10, 13, 0, 7, 9, 0, 14, 9, 6, 3, 3, 4, 15, 6, 5, 10, + 1, 2, 13, 8, 12, 5, 7, 14, 11, 12, 4, 11, 2, 15, 8, 1, + 13, 1, 6, 10, 4, 13, 9, 0, 8, 6, 15, 9, 3, 8, 0, 7, + 11, 4, 1, 15, 2, 14, 12, 3, 5, 11, 10, 5, 14, 2, 7, 12 + ), + array( + 7, 13, 13, 8, 14, 11, 3, 5, 0, 6, 6, 15, 9, 0, 10, 3, + 1, 4, 2, 7, 8, 2, 5, 12, 11, 1, 12, 10, 4, 14, 15, 9, + 10, 3, 6, 15, 9, 0, 0, 6, 12, 10, 11, 1, 7, 13, 13, 8, + 15, 9, 1, 4, 3, 5, 14, 11, 5, 12, 2, 7, 8, 2, 4, 14 + ), + array( + 2, 14, 12, 11, 4, 2, 1, 12, 7, 4, 10, 7, 11, 13, 6, 1, + 8, 5, 5, 0, 3, 15, 15, 10, 13, 3, 0, 9, 14, 8, 9, 6, + 4, 11, 2, 8, 1, 12, 11, 7, 10, 1, 13, 14, 7, 2, 8, 13, + 15, 6, 9, 15, 12, 0, 5, 9, 6, 10, 3, 4, 0, 5, 14, 3 + ), + array( + 12, 10, 1, 15, 10, 4, 15, 2, 9, 7, 2, 12, 6, 9, 8, 5, + 0, 6, 13, 1, 3, 13, 4, 14, 14, 0, 7, 11, 5, 3, 11, 8, + 9, 4, 14, 3, 15, 2, 5, 12, 2, 9, 8, 5, 12, 15, 3, 10, + 7, 11, 0, 14, 4, 1, 10, 7, 1, 6, 13, 0, 11, 8, 6, 13 + ), + array( + 4, 13, 11, 0, 2, 11, 14, 7, 15, 4, 0, 9, 8, 1, 13, 10, + 3, 14, 12, 3, 9, 5, 7, 12, 5, 2, 10, 15, 6, 8, 1, 6, + 1, 6, 4, 11, 11, 13, 13, 8, 12, 1, 3, 4, 7, 10, 14, 7, + 10, 9, 15, 5, 6, 0, 8, 15, 0, 14, 5, 2, 9, 3, 2, 12 + ), + array( + 13, 1, 2, 15, 8, 13, 4, 8, 6, 10, 15, 3, 11, 7, 1, 4, + 10, 12, 9, 5, 3, 6, 14, 11, 5, 0, 0, 14, 12, 9, 7, 2, + 7, 2, 11, 1, 4, 14, 1, 7, 9, 4, 12, 10, 14, 8, 2, 13, + 0, 15, 6, 12, 10, 9, 13, 0, 15, 3, 3, 5, 5, 6, 8, 11 + ) + ); + + $temp = unpack('Na/Nb', $block); + $block = array($temp['a'], $temp['b']); + + // because php does arithmetic right shifts, if the most significant bits are set, right + // shifting those into the correct position will add 1's - not 0's. this will intefere + // with the | operation unless a second & is done. so we isolate these bits and left shift + // them into place. we then & each block with 0x7FFFFFFF to prevennt 1's from being added + // for any other shifts. + $msb = array( + ($block[0] >> 31) & 1, + ($block[1] >> 31) & 1 + ); + $block[0] &= 0x7FFFFFFF; + $block[1] &= 0x7FFFFFFF; + + // we isolate the appropriate bit in the appropriate integer and shift as appropriate. in + // some cases, there are going to be multiple bits in the same integer that need to be shifted + // in the same way. we combine those into one shift operation. + $block = array( + (($block[1] & 0x00000040) << 25) | (($block[1] & 0x00004000) << 16) | + (($block[1] & 0x00400001) << 7) | (($block[1] & 0x40000100) >> 2) | + (($block[0] & 0x00000040) << 21) | (($block[0] & 0x00004000) << 12) | + (($block[0] & 0x00400001) << 3) | (($block[0] & 0x40000100) >> 6) | + (($block[1] & 0x00000010) << 19) | (($block[1] & 0x00001000) << 10) | + (($block[1] & 0x00100000) << 1) | (($block[1] & 0x10000000) >> 8) | + (($block[0] & 0x00000010) << 15) | (($block[0] & 0x00001000) << 6) | + (($block[0] & 0x00100000) >> 3) | (($block[0] & 0x10000000) >> 12) | + (($block[1] & 0x00000004) << 13) | (($block[1] & 0x00000400) << 4) | + (($block[1] & 0x00040000) >> 5) | (($block[1] & 0x04000000) >> 14) | + (($block[0] & 0x00000004) << 9) | ( $block[0] & 0x00000400 ) | + (($block[0] & 0x00040000) >> 9) | (($block[0] & 0x04000000) >> 18) | + (($block[1] & 0x00010000) >> 11) | (($block[1] & 0x01000000) >> 20) | + (($block[0] & 0x00010000) >> 15) | (($block[0] & 0x01000000) >> 24) + , + (($block[1] & 0x00000080) << 24) | (($block[1] & 0x00008000) << 15) | + (($block[1] & 0x00800002) << 6) | (($block[0] & 0x00000080) << 20) | + (($block[0] & 0x00008000) << 11) | (($block[0] & 0x00800002) << 2) | + (($block[1] & 0x00000020) << 18) | (($block[1] & 0x00002000) << 9) | + ( $block[1] & 0x00200000 ) | (($block[1] & 0x20000000) >> 9) | + (($block[0] & 0x00000020) << 14) | (($block[0] & 0x00002000) << 5) | + (($block[0] & 0x00200000) >> 4) | (($block[0] & 0x20000000) >> 13) | + (($block[1] & 0x00000008) << 12) | (($block[1] & 0x00000800) << 3) | + (($block[1] & 0x00080000) >> 6) | (($block[1] & 0x08000000) >> 15) | + (($block[0] & 0x00000008) << 8) | (($block[0] & 0x00000800) >> 1) | + (($block[0] & 0x00080000) >> 10) | (($block[0] & 0x08000000) >> 19) | + (($block[1] & 0x00000200) >> 3) | (($block[0] & 0x00000200) >> 7) | + (($block[1] & 0x00020000) >> 12) | (($block[1] & 0x02000000) >> 21) | + (($block[0] & 0x00020000) >> 16) | (($block[0] & 0x02000000) >> 25) | + ($msb[1] << 28) | ($msb[0] << 24) + ); + + for ($i = 0; $i < 16; $i++) + { + // start of "the Feistel (F) function" - see the following URL: + // http://en.wikipedia.org/wiki/Image:Data_Encryption_Standard_InfoBox_Diagram.png + $temp = (($sbox[0][((($block[1] >> 27) & 0x1F) | (($block[1] & 1) << 5)) ^ $this->keys[$mode][$i][0]]) << 28) + | (($sbox[1][(($block[1] & 0x1F800000) >> 23) ^ $this->keys[$mode][$i][1]]) << 24) + | (($sbox[2][(($block[1] & 0x01F80000) >> 19) ^ $this->keys[$mode][$i][2]]) << 20) + | (($sbox[3][(($block[1] & 0x001F8000) >> 15) ^ $this->keys[$mode][$i][3]]) << 16) + | (($sbox[4][(($block[1] & 0x0001F800) >> 11) ^ $this->keys[$mode][$i][4]]) << 12) + | (($sbox[5][(($block[1] & 0x00001F80) >> 7) ^ $this->keys[$mode][$i][5]]) << 8) + | (($sbox[6][(($block[1] & 0x000001F8) >> 3) ^ $this->keys[$mode][$i][6]]) << 4) + | ( $sbox[7][((($block[1] & 0x1F) << 1) | (($block[1] >> 31) & 1)) ^ $this->keys[$mode][$i][7]]); + + $msb = ($temp >> 31) & 1; + $temp &= 0x7FFFFFFF; + $newBlock = (($temp & 0x00010000) << 15) | (($temp & 0x02020120) << 5) + | (($temp & 0x00001800) << 17) | (($temp & 0x01000000) >> 10) + | (($temp & 0x00000008) << 24) | (($temp & 0x00100000) << 6) + | (($temp & 0x00000010) << 21) | (($temp & 0x00008000) << 9) + | (($temp & 0x00000200) << 12) | (($temp & 0x10000000) >> 27) + | (($temp & 0x00000040) << 14) | (($temp & 0x08000000) >> 8) + | (($temp & 0x00004000) << 4) | (($temp & 0x00000002) << 16) + | (($temp & 0x00442000) >> 6) | (($temp & 0x40800000) >> 15) + | (($temp & 0x00000001) << 11) | (($temp & 0x20000000) >> 20) + | (($temp & 0x00080000) >> 13) | (($temp & 0x00000004) << 3) + | (($temp & 0x04000000) >> 22) | (($temp & 0x00000480) >> 7) + | (($temp & 0x00200000) >> 19) | ($msb << 23); + // end of "the Feistel (F) function" - $newBlock is F's output + + $temp = $block[1]; + $block[1] = $block[0] ^ $newBlock; + $block[0] = $temp; + } + + $msb = array( + ($block[0] >> 31) & 1, + ($block[1] >> 31) & 1 + ); + $block[0] &= 0x7FFFFFFF; + $block[1] &= 0x7FFFFFFF; + + $block = array( + (($block[0] & 0x01000004) << 7) | (($block[1] & 0x01000004) << 6) | + (($block[0] & 0x00010000) << 13) | (($block[1] & 0x00010000) << 12) | + (($block[0] & 0x00000100) << 19) | (($block[1] & 0x00000100) << 18) | + (($block[0] & 0x00000001) << 25) | (($block[1] & 0x00000001) << 24) | + (($block[0] & 0x02000008) >> 2) | (($block[1] & 0x02000008) >> 3) | + (($block[0] & 0x00020000) << 4) | (($block[1] & 0x00020000) << 3) | + (($block[0] & 0x00000200) << 10) | (($block[1] & 0x00000200) << 9) | + (($block[0] & 0x00000002) << 16) | (($block[1] & 0x00000002) << 15) | + (($block[0] & 0x04000000) >> 11) | (($block[1] & 0x04000000) >> 12) | + (($block[0] & 0x00040000) >> 5) | (($block[1] & 0x00040000) >> 6) | + (($block[0] & 0x00000400) << 1) | ( $block[1] & 0x00000400 ) | + (($block[0] & 0x08000000) >> 20) | (($block[1] & 0x08000000) >> 21) | + (($block[0] & 0x00080000) >> 14) | (($block[1] & 0x00080000) >> 15) | + (($block[0] & 0x00000800) >> 8) | (($block[1] & 0x00000800) >> 9) + , + (($block[0] & 0x10000040) << 3) | (($block[1] & 0x10000040) << 2) | + (($block[0] & 0x00100000) << 9) | (($block[1] & 0x00100000) << 8) | + (($block[0] & 0x00001000) << 15) | (($block[1] & 0x00001000) << 14) | + (($block[0] & 0x00000010) << 21) | (($block[1] & 0x00000010) << 20) | + (($block[0] & 0x20000080) >> 6) | (($block[1] & 0x20000080) >> 7) | + ( $block[0] & 0x00200000 ) | (($block[1] & 0x00200000) >> 1) | + (($block[0] & 0x00002000) << 6) | (($block[1] & 0x00002000) << 5) | + (($block[0] & 0x00000020) << 12) | (($block[1] & 0x00000020) << 11) | + (($block[0] & 0x40000000) >> 15) | (($block[1] & 0x40000000) >> 16) | + (($block[0] & 0x00400000) >> 9) | (($block[1] & 0x00400000) >> 10) | + (($block[0] & 0x00004000) >> 3) | (($block[1] & 0x00004000) >> 4) | + (($block[0] & 0x00800000) >> 18) | (($block[1] & 0x00800000) >> 19) | + (($block[0] & 0x00008000) >> 12) | (($block[1] & 0x00008000) >> 13) | + ($msb[0] << 7) | ($msb[1] << 6) + ); + + return pack('NN', $block[0], $block[1]); + } + + /** + * Creates the key schedule. + * + * @access private + * @param String $key + * @return Array + */ + function _prepare_key($key) + { + static $shifts = array( // number of key bits shifted per round + 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 + ); + + // pad the key and remove extra characters as appropriate. + $key = str_pad(substr($key, 0, 8), 8, chr(0)); + + $temp = unpack('Na/Nb', $key); + $key = array($temp['a'], $temp['b']); + $msb = array( + ($key[0] >> 31) & 1, + ($key[1] >> 31) & 1 + ); + $key[0] &= 0x7FFFFFFF; + $key[1] &= 0x7FFFFFFF; + + $key = array( + (($key[1] & 0x00000002) << 26) | (($key[1] & 0x00000204) << 17) | + (($key[1] & 0x00020408) << 8) | (($key[1] & 0x02040800) >> 1) | + (($key[0] & 0x00000002) << 22) | (($key[0] & 0x00000204) << 13) | + (($key[0] & 0x00020408) << 4) | (($key[0] & 0x02040800) >> 5) | + (($key[1] & 0x04080000) >> 10) | (($key[0] & 0x04080000) >> 14) | + (($key[1] & 0x08000000) >> 19) | (($key[0] & 0x08000000) >> 23) | + (($key[0] & 0x00000010) >> 1) | (($key[0] & 0x00001000) >> 10) | + (($key[0] & 0x00100000) >> 19) | (($key[0] & 0x10000000) >> 28) + , + (($key[1] & 0x00000080) << 20) | (($key[1] & 0x00008000) << 11) | + (($key[1] & 0x00800000) << 2) | (($key[0] & 0x00000080) << 16) | + (($key[0] & 0x00008000) << 7) | (($key[0] & 0x00800000) >> 2) | + (($key[1] & 0x00000040) << 13) | (($key[1] & 0x00004000) << 4) | + (($key[1] & 0x00400000) >> 5) | (($key[1] & 0x40000000) >> 14) | + (($key[0] & 0x00000040) << 9) | ( $key[0] & 0x00004000 ) | + (($key[0] & 0x00400000) >> 9) | (($key[0] & 0x40000000) >> 18) | + (($key[1] & 0x00000020) << 6) | (($key[1] & 0x00002000) >> 3) | + (($key[1] & 0x00200000) >> 12) | (($key[1] & 0x20000000) >> 21) | + (($key[0] & 0x00000020) << 2) | (($key[0] & 0x00002000) >> 7) | + (($key[0] & 0x00200000) >> 16) | (($key[0] & 0x20000000) >> 25) | + (($key[1] & 0x00000010) >> 1) | (($key[1] & 0x00001000) >> 10) | + (($key[1] & 0x00100000) >> 19) | (($key[1] & 0x10000000) >> 28) | + ($msb[1] << 24) | ($msb[0] << 20) + ); + + $keys = array(); + for ($i = 0; $i < 16; $i++) + { + $key[0] <<= $shifts[$i]; + $temp = ($key[0] & 0xF0000000) >> 28; + $key[0] = ($key[0] | $temp) & 0x0FFFFFFF; + + $key[1] <<= $shifts[$i]; + $temp = ($key[1] & 0xF0000000) >> 28; + $key[1] = ($key[1] | $temp) & 0x0FFFFFFF; + + $temp = array( + (($key[1] & 0x00004000) >> 9) | (($key[1] & 0x00000800) >> 7) | + (($key[1] & 0x00020000) >> 14) | (($key[1] & 0x00000010) >> 2) | + (($key[1] & 0x08000000) >> 26) | (($key[1] & 0x00800000) >> 23) + , + (($key[1] & 0x02400000) >> 20) | (($key[1] & 0x00000001) << 4) | + (($key[1] & 0x00002000) >> 10) | (($key[1] & 0x00040000) >> 18) | + (($key[1] & 0x00000080) >> 6) + , + ( $key[1] & 0x00000020 ) | (($key[1] & 0x00000200) >> 5) | + (($key[1] & 0x00010000) >> 13) | (($key[1] & 0x01000000) >> 22) | + (($key[1] & 0x00000004) >> 1) | (($key[1] & 0x00100000) >> 20) + , + (($key[1] & 0x00001000) >> 7) | (($key[1] & 0x00200000) >> 17) | + (($key[1] & 0x00000002) << 2) | (($key[1] & 0x00000100) >> 6) | + (($key[1] & 0x00008000) >> 14) | (($key[1] & 0x04000000) >> 26) + , + (($key[0] & 0x00008000) >> 10) | ( $key[0] & 0x00000010 ) | + (($key[0] & 0x02000000) >> 22) | (($key[0] & 0x00080000) >> 17) | + (($key[0] & 0x00000200) >> 8) | (($key[0] & 0x00000002) >> 1) + , + (($key[0] & 0x04000000) >> 21) | (($key[0] & 0x00010000) >> 12) | + (($key[0] & 0x00000020) >> 2) | (($key[0] & 0x00000800) >> 9) | + (($key[0] & 0x00800000) >> 22) | (($key[0] & 0x00000100) >> 8) + , + (($key[0] & 0x00001000) >> 7) | (($key[0] & 0x00000088) >> 3) | + (($key[0] & 0x00020000) >> 14) | (($key[0] & 0x00000001) << 2) | + (($key[0] & 0x00400000) >> 21) + , + (($key[0] & 0x00000400) >> 5) | (($key[0] & 0x00004000) >> 10) | + (($key[0] & 0x00000040) >> 3) | (($key[0] & 0x00100000) >> 18) | + (($key[0] & 0x08000000) >> 26) | (($key[0] & 0x01000000) >> 24) + ); + + $keys[] = $temp; + } + + $temp = array( + CRYPT_DES_ENCRYPT => $keys, + CRYPT_DES_DECRYPT => array_reverse($keys) + ); + + return $temp; + } +} + + + +/** + * Pure-PHP implementation of Triple DES. + * + * @author Jim Wigginton + * @version 0.1.0 + * @access public + * @package Crypt_TerraDES + */ +class tripledes +{ + /** + * The Three Keys + * + * @see tripledes::setKey() + * @var String + * @access private + */ + var $key = "\0\0\0\0\0\0\0\0"; + + /** + * The Encryption Mode + * + * @see tripledes::tripledes() + * @var Integer + * @access private + */ + var $mode = CRYPT_DES_MODE_CBC; + + /** + * Continuous Buffer status + * + * @see tripledes::enableContinuousBuffer() + * @var Boolean + * @access private + */ + var $continuousBuffer = false; + + /** + * Padding status + * + * @see tripledes::enablePadding() + * @var Boolean + * @access private + */ + var $padding = true; + + /** + * The Initialization Vector + * + * @see tripledes::setIV() + * @var String + * @access private + */ + var $iv = "\0\0\0\0\0\0\0\0"; + + /** + * A "sliding" Initialization Vector + * + * @see tripledes::enableContinuousBuffer() + * @var String + * @access private + */ + var $encryptIV = "\0\0\0\0\0\0\0\0"; + + /** + * A "sliding" Initialization Vector + * + * @see tripledes::enableContinuousBuffer() + * @var String + * @access private + */ + var $decryptIV = "\0\0\0\0\0\0\0\0"; + + /** + * MCrypt parameters + * + * @see tripledes::setMCrypt() + * @var Array + * @access private + */ + var $mcrypt = array('', ''); + + /** + * The des objects + * + * @var Array + * @access private + */ + var $des; + + /** + * Default Constructor. + * + * Determines whether or not the mcrypt extension should be used. $mode should only, at present, be + * CRYPT_DES_MODE_ECB or CRYPT_DES_MODE_CBC. If not explictly set, CRYPT_DES_MODE_CBC will be used. + * + * @param optional Integer $mode + * @return tripledes + * @access public + */ + function __construct($mode = CRYPT_DES_MODE_CBC) + { + if ( !defined('CRYPT_DES_MODE') ) + { + switch (true) + { + case extension_loaded('mcrypt'): + // i'd check to see if des was supported, by doing in_array('des', mcrypt_list_algorithms('')), + // but since that can be changed after the object has been created, there doesn't seem to be + // a lot of point... + define('CRYPT_DES_MODE', CRYPT_DES_MODE_MCRYPT); + break; + default: + define('CRYPT_DES_MODE', CRYPT_DES_MODE_INTERNAL); + } + } + + if ( $mode == CRYPT_DES_MODE_3CBC ) + { + $this->mode = CRYPT_DES_MODE_3CBC; + $this->des = array( + new des(CRYPT_DES_MODE_CBC), + new des(CRYPT_DES_MODE_CBC), + new des(CRYPT_DES_MODE_CBC) + ); + + // we're going to be doing the padding, ourselves, so disable it in the des objects + $this->des[0]->disable_padding(); + $this->des[1]->disable_padding(); + $this->des[2]->disable_padding(); + + return; + } + + switch ( CRYPT_DES_MODE ) + { + case CRYPT_DES_MODE_MCRYPT: + switch ($mode) + { + case CRYPT_DES_MODE_ECB: + $this->mode = MCRYPT_MODE_ECB; break; + case CRYPT_DES_MODE_CBC: + default: + $this->mode = MCRYPT_MODE_CBC; + } + + break; + default: + $this->des = array( + new des(CRYPT_DES_MODE_ECB), + new des(CRYPT_DES_MODE_ECB), + new des(CRYPT_DES_MODE_ECB) + ); + + // we're going to be doing the padding, ourselves, so disable it in the des objects + $this->des[0]->disable_padding(); + $this->des[1]->disable_padding(); + $this->des[2]->disable_padding(); + + switch ($mode) + { + case CRYPT_DES_MODE_ECB: + case CRYPT_DES_MODE_CBC: + $this->mode = $mode; + break; + default: + $this->mode = CRYPT_DES_MODE_CBC; + } + } + } + + /** + * Sets the key. + * + * Keys can be of any length. Triple DES, itself, can use 128-bit (eg. strlen($key) == 16) or + * 192-bit (eg. strlen($key) == 24) keys. This function pads and truncates $key as appropriate. + * + * DES also requires that every eighth bit be a parity bit, however, we'll ignore that. + * + * If the key is not explicitly set, it'll be assumed to be all zero's. + * + * @access public + * @param String $key + */ + function set_key($key) + { + $length = strlen($key); + if ($length > 8) + { + $key = str_pad($key, 24, chr(0)); + // if $key is between 64 and 128-bits, use the first 64-bits as the last, per this: + // http://php.net/function.mcrypt-encrypt#47973 + $key = $length <= 16 ? substr_replace($key, substr($key, 0, 8), 16) : substr($key, 0, 24); + } + $this->key = $key; + switch (true) + { + case CRYPT_DES_MODE == CRYPT_DES_MODE_INTERNAL: + case $this->mode == CRYPT_DES_MODE_3CBC: + $this->des[0]->set_key(substr($key, 0, 8)); + $this->des[1]->set_key(substr($key, 8, 8)); + $this->des[2]->set_key(substr($key, 16, 8)); + } + } + + /** + * Sets the initialization vector. (optional) + * + * SetIV is not required when CRYPT_DES_MODE_ECB is being used. If not explictly set, it'll be assumed + * to be all zero's. + * + * @access public + * @param String $iv + */ + function set_iv($iv) + { + $this->encryptIV = $this->decryptIV = $this->iv = str_pad(substr($iv, 0, 8), 8, chr(0)); + if ($this->mode == CRYPT_DES_MODE_3CBC) + { + $this->des[0]->set_iv($iv); + $this->des[1]->set_iv($iv); + $this->des[2]->set_iv($iv); + } + } + + /** + * Sets MCrypt parameters. (optional) + * + * If MCrypt is being used, empty strings will be used, unless otherwise specified. + * + * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open + * @access public + * @param optional Integer $algorithm_directory + * @param optional Integer $mode_directory + */ + function set_mcrypt($algorithm_directory = '', $mode_directory = '') + { + $this->mcrypt = array($algorithm_directory, $mode_directory); + if ( $this->mode == CRYPT_DES_MODE_3CBC ) + { + $this->des[0]->set_mcrypt($algorithm_directory, $mode_directory); + $this->des[1]->set_mcrypt($algorithm_directory, $mode_directory); + $this->des[2]->set_mcrypt($algorithm_directory, $mode_directory); + } + } + + /** + * Encrypts a message. + * + * @access public + * @param String $plaintext + */ + function encrypt($plaintext) + { + $plaintext = $this->_pad($plaintext); + + // if the key is smaller then 8, do what we'd normally do + if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) + { + $ciphertext = $this->des[2]->encrypt($this->des[1]->decrypt($this->des[0]->encrypt($plaintext))); + + return $ciphertext; + } + + if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) + { + $td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]); + mcrypt_generic_init($td, $this->key, $this->encryptIV); + + $ciphertext = mcrypt_generic($td, $plaintext); + + mcrypt_generic_deinit($td); + mcrypt_module_close($td); + + if ($this->continuousBuffer) + { + $this->encryptIV = substr($ciphertext, -8); + } + + return $ciphertext; + } + + if (strlen($this->key) <= 8) + { + $this->des[0]->mode = $this->mode; + + return $this->des[0]->encrypt($plaintext); + } + + // we pad with chr(0) since that's what mcrypt_generic does. to quote from http://php.net/function.mcrypt-generic : + // "The data is padded with "\0" to make sure the length of the data is n * blocksize." + $plaintext = str_pad($plaintext, ceil(strlen($plaintext) / 8) * 8, chr(0)); + + $ciphertext = ''; + switch ($this->mode) + { + case CRYPT_DES_MODE_ECB: + for ($i = 0; $i < strlen($plaintext); $i+=8) + { + $block = substr($plaintext, $i, 8); + $block = $this->des[0]->_process_block($block, CRYPT_DES_ENCRYPT); + $block = $this->des[1]->_process_block($block, CRYPT_DES_DECRYPT); + $block = $this->des[2]->_process_block($block, CRYPT_DES_ENCRYPT); + $ciphertext.= $block; + } + break; + case CRYPT_DES_MODE_CBC: + $xor = $this->encryptIV; + for ($i = 0; $i < strlen($plaintext); $i+=8) + { + $block = substr($plaintext, $i, 8) ^ $xor; + $block = $this->des[0]->_process_block($block, CRYPT_DES_ENCRYPT); + $block = $this->des[1]->_process_block($block, CRYPT_DES_DECRYPT); + $block = $this->des[2]->_process_block($block, CRYPT_DES_ENCRYPT); + $xor = $block; + $ciphertext.= $block; + } + if ($this->continuousBuffer) + { + $this->encryptIV = $xor; + } + } + + return $ciphertext; + } + + /** + * Decrypts a message. + * + * @access public + * @param String $ciphertext + */ + function decrypt($ciphertext) + { + if ($this->mode == CRYPT_DES_MODE_3CBC && strlen($this->key) > 8) + { + $plaintext = $this->des[0]->decrypt($this->des[1]->encrypt($this->des[2]->decrypt($ciphertext))); + + return $this->_unpad($plaintext); + } + + // we pad with chr(0) since that's what mcrypt_generic does. to quote from http://php.net/function.mcrypt-generic : + // "The data is padded with "\0" to make sure the length of the data is n * blocksize." + $ciphertext = str_pad($ciphertext, (strlen($ciphertext) + 7) & 0xFFFFFFF8, chr(0)); + + if ( CRYPT_DES_MODE == CRYPT_DES_MODE_MCRYPT ) + { + $td = mcrypt_module_open(MCRYPT_3DES, $this->mcrypt[0], $this->mode, $this->mcrypt[1]); + mcrypt_generic_init($td, $this->key, $this->decryptIV); + + $plaintext = mdecrypt_generic($td, $ciphertext); + + mcrypt_generic_deinit($td); + mcrypt_module_close($td); + + if ($this->continuousBuffer) + { + $this->decryptIV = substr($ciphertext, -8); + } + + return $this->_unpad($plaintext); + } + + if (strlen($this->key) <= 8) + { + $this->des[0]->mode = $this->mode; + + return $this->_unpad($this->des[0]->decrypt($plaintext)); + } + + $plaintext = ''; + switch ($this->mode) + { + case CRYPT_DES_MODE_ECB: + for ($i = 0; $i < strlen($ciphertext); $i+=8) + { + $block = substr($ciphertext, $i, 8); + $block = $this->des[2]->_process_block($block, CRYPT_DES_DECRYPT); + $block = $this->des[1]->_process_block($block, CRYPT_DES_ENCRYPT); + $block = $this->des[0]->_process_block($block, CRYPT_DES_DECRYPT); + $plaintext.= $block; + } + break; + case CRYPT_DES_MODE_CBC: + $xor = $this->decryptIV; + for ($i = 0; $i < strlen($ciphertext); $i+=8) + { + $orig = $block = substr($ciphertext, $i, 8); + $block = $this->des[2]->_process_block($block, CRYPT_DES_DECRYPT); + $block = $this->des[1]->_process_block($block, CRYPT_DES_ENCRYPT); + $block = $this->des[0]->_process_block($block, CRYPT_DES_DECRYPT); + $plaintext.= $block ^ $xor; + $xor = $orig; + } + if ($this->continuousBuffer) + { + $this->decryptIV = $xor; + } + } + + return $this->_unpad($plaintext); + } + + /** + * Treat consecutive "packets" as if they are a continuous buffer. + * + * Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets + * will yield different outputs: + * + * + * echo $des->encrypt(substr($plaintext, 0, 8)); + * echo $des->encrypt(substr($plaintext, 8, 8)); + * + * + * echo $des->encrypt($plaintext); + * + * + * The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates + * another, as demonstrated with the following: + * + * + * $des->encrypt(substr($plaintext, 0, 8)); + * echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); + * + * + * echo $des->decrypt($des->encrypt(substr($plaintext, 8, 8))); + * + * + * With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different + * outputs. The reason is due to the fact that the initialization vector's change after every encryption / + * decryption round when the continuous buffer is enabled. When it's disabled, they remain constant. + * + * Put another way, when the continuous buffer is enabled, the state of the des() object changes after each + * encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that + * continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them), + * however, they are also less intuitive and more likely to cause you problems. + * + * @see tripledes::disableContinuousBuffer() + * @access public + */ + function enable_continuous_buffer() + { + $this->continuousBuffer = true; + if ($this->mode == CRYPT_DES_MODE_3CBC) + { + $this->des[0]->enable_continuous_buffer(); + $this->des[1]->enable_continuous_buffer(); + $this->des[2]->enable_continuous_buffer(); + } + } + + /** + * Treat consecutive packets as if they are a discontinuous buffer. + * + * The default behavior. + * + * @see tripledes::enableContinuousBuffer() + * @access public + */ + function disable_continuous_buffer() + { + $this->continuousBuffer = false; + $this->encryptIV = $this->iv; + $this->decryptIV = $this->iv; + + if ($this->mode == CRYPT_DES_MODE_3CBC) + { + $this->des[0]->disable_continuous_buffer(); + $this->des[1]->disable_continuous_buffer(); + $this->des[2]->disable_continuous_buffer(); + } + } + + /** + * Pad "packets". + * + * DES works by encrypting eight bytes at a time. If you ever need to encrypt or decrypt something that's not + * a multiple of eight, it becomes necessary to pad the input so that it's length is a multiple of eight. + * + * Padding is enabled by default. Sometimes, however, it is undesirable to pad strings. Such is the case in SSH1, + * where "packets" are padded with random bytes before being encrypted. Unpad these packets and you risk stripping + * away characters that shouldn't be stripped away. (SSH knows how many bytes are added because the length is + * transmitted separately) + * + * @see tripledes::disable_padding() + * @access public + */ + function enable_padding() + { + $this->padding = true; + } + + /** + * Do not pad packets. + * + * @see tripledes::enablePadding() + * @access public + */ + function disable_padding() + { + $this->padding = false; + } + + /** + * Pads a string + * + * Pads a string using the RSA PKCS padding standards so that its length is a multiple of the blocksize (8). + * 8 - (strlen($text) & 7) bytes are added, each of which is equal to chr(8 - (strlen($text) & 7) + * + * If padding is disabled and $text is not a multiple of the blocksize, the string will be padded regardless + * and padding will, hence forth, be enabled. + * + * @see tripledes::_unpad() + * @access private + */ + function _pad($text) + { + $length = strlen($text); + + if (!$this->padding) + { + if (($length & 7) == 0) + { + return $text; + } + else + { + $this->padding = true; + } + } + + $pad = 8 - ($length & 7); + return str_pad($text, $length + $pad, chr($pad)); + } + + /** + * Unpads a string + * + * If padding is enabled and the reported padding length exceeds the block size, padding will be, hence forth, disabled. + * + * @see tripledes::_pad() + * @access private + */ + function _unpad($text) + { + if (!$this->padding) + { + return $text; + } + + $length = ord($text[strlen($text) - 1]); + + if ($length > 8) + { + $this->padding = false; + return $text; + } + + return substr($text, 0, -$length); + } +} + +?> \ No newline at end of file -- cgit v1.2.1