69 lines
2.5 KiB
PHP
69 lines
2.5 KiB
PHP
<?php
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set_include_path(get_include_path().PATH_SEPARATOR.dirname(__FILE__).DIRECTORY_SEPARATOR.'libpy2php');
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require_once 'libpy2php.php';
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require_once 'AES.class.php';
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class crypt
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{
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public function ige_encrypt($message, $key, $iv)
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{
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return _ige($message, $key, $iv, 'encrypt');
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}
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public function ige_decrypt($message, $key, $iv)
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{
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return _ige($message, $key, $iv, 'decrypt');
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}
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/**
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* Given a key, given an iv, and message
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* do whatever operation asked in the operation field.
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* Operation will be checked for: "decrypt" and "encrypt" strings.
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* Returns the message encrypted/decrypted.
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* message must be a multiple by 16 bytes (for division in 16 byte blocks)
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* key must be 32 byte
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* iv must be 32 byte (it's not internally used in AES 256 ECB, but it's
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* needed for IGE).
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*/
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public function _ige($message, $key, $iv, $operation = 'decrypt')
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{
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$message = str_split($message);
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if ((len($key) != 32)) {
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throw new Exception('key must be 32 bytes long (was '.len($key).' bytes)');
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}
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if ((len($iv) != 32)) {
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throw new Exception('iv must be 32 bytes long (was '.len($iv).' bytes)');
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}
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$cipher = new AES($key);
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$cipher = $cipher->encrypt($iv);
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$blocksize = $cipher->block_size;
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if ((len($message) % $blocksize) != 0) {
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throw new Exception('message must be a multiple of 16 bytes (try adding '.(16 - (count($message) % 16)).' bytes of padding)');
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}
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$ivp = substr($iv, 0, $blocksize - 0);
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$ivp2 = substr($iv, $blocksize, null);
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$ciphered = null;
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foreach (pyjslib_range(0, len($message), $blocksize) as $i) {
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$indata = substr($message, $i, ($i + $blocksize) - $i);
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if (($operation == 'decrypt')) {
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$xored = strxor($indata, $ivp2);
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$decrypt_xored = $cipher->decrypt($xored);
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$outdata = strxor($decrypt_xored, $ivp);
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$ivp = $indata;
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$ivp2 = $outdata;
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} elseif (($operation == 'encrypt')) {
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$xored = strxor($indata, $ivp);
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$encrypt_xored = $cipher->encrypt($xored);
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$outdata = strxor($encrypt_xored, $ivp2);
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$ivp = $outdata;
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$ivp2 = $indata;
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} else {
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throw new Exception('operation must be either \'decrypt\' or \'encrypt\'');
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}
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$ciphered .= $outdata;
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}
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return $ciphered;
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}
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}
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