note 43696 added to function.md5

Below is MD5-based block cypher (MDC-like), which works in 128bit CFB mode. It is very useful to encrypt secret data before transfer it over the network. $iv_len - initialization vector's length. 0 <= $iv_len <= 512 <?php function get_rnd_iv($iv_len) { $iv = ''; while ($iv_len-- > 0) { $iv .= chr(mt_rand() & 0xff); } return $iv; } function md5_encrypt($plain_text, $password, $iv_len = 16) { $plain_text .= "\x13"; $n = strlen($plain_text); if ($n % 16) $plain_text .= str_repeat("\0", 16 - ($n % 16)); $i = 0; $enc_text = get_rnd_iv($iv_len); $iv = substr($password ^ $enc_text, 0, 512); while ($i < $n) { $block = substr($plain_text, $i, 16) ^ pack('H*', md5($iv)); $enc_text .= $block; $iv = substr($block . $iv, 0, 512) ^ $password; $i += 16; } return base64_encode($enc_text); } function md5_decrypt($enc_text, $password, $iv_len = 16) { $enc_text = base64_decode($enc_text); $n = strlen($enc_text); $i = $iv_len; $plain_text = ''; $iv = substr($password ^ substr($enc_text, 0, $iv_len), 0, 512); while ($i < $n) { $block = substr($enc_text, $i, 16); $plain_text .= $block ^ pack('H*', md5($iv)); $iv = substr($block . $iv, 0, 512) ^ $password; $i += 16; } return preg_replace('/\\x13\\x00*$/', '', $plain_text); } /******************************************/ $plain_text = 'very secret string'; $password = 'very secret password'; echo "plain text is: [${plain_text}]<br />\n"; echo "password is: [${password}]<br />\n"; $enc_text = md5_encrypt($plain_text, $password); echo "encrypted text is: [${enc_text}]<br />\n"; $plain_text2 = md5_decrypt($enc_text, $password); echo "decrypted text is: [${plain_text2}]<br />\n"; ?> ---- Manual Page -- http://www.php.net/manual/en/function.md5.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+43696 Delete -- http://master.php.net/manage/user-notes.php?action=delete+43696&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+43696&report=yes Search -- http://master.php.net/manage/user-notes.php