Online PHP editor | rfc for nRfCI

<?php $data = "wpdPVWejqNRYqDTeUJ2Iw06/rnfHAoy5jtgTojiilD0="; $pwd = "ICS2015"; $salt = "7"; $dec = Decrypt($data, $pwd, $salt); // Remove the padding echo "Dec: " . $dec . "\r\n"; function Decrypt($ciphertext, $password, $salt) { $ciphertext = base64_decode($ciphertext); $key = PBKDF1($password, $salt, 100, 32); $iv = PBKDF1($password, $salt, 100, 16); // NB: Need 128 not 256 and CBC mode to be compatible $decpad = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $ciphertext, MCRYPT_MODE_CBC, $iv); $pad = ord($decpad[($len = strlen($decpad)) - 1]); $dec = substr($decpad, 0, strlen($decpad) - $pad); return $dec; } function Encrypt($encrypt, $password) { $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND); $passcrypt = trim(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $password, trim($encrypt), MCRYPT_MODE_ECB, $iv)); $encode = base64_encode($passcrypt); return $encode; } function PBKDF1($pass, $salt, $count, $cb) { // This is very approximately the way that the Microsoft version of // PasswordDeriveBytes works. /// /// !!!WARNING!!! /// // This is a BAD function! // Irrespective of the fact that the use of PBKDF1 is not recommended anyway. // // This really should be put into a class with a constructor taking the // $pass, $salt and $count. // Then there should be a Reset() method to start from scratch each time a new pwd/salt is used. // And there should be a GetBytes(int) method to get the required info. // But for the sake of simplicity we are assuming the same pwd and salt for each call to // this function. This will not stand up to any scrutiny! static $base; static $extra; static $extracount= 0; static $hashno; static $state = 0; if ($state == 0) { $hashno = 0; $state = 1; $key = $pass . $salt; $base = sha1($key, true); for($i = 2; $i < $count; $i++) { $base = sha1($base, true); } } $result = ""; // Check if we have any bytes left over from a previous iteration. // This is the way MS appears to do it. To me it looks very badly wrong // in the line: "$result = substr($extra, $rlen, $rlen);" // I'm sure it should be more like "$result = substr($extra, $extracount, $rlen);" // Mono have provided what looks like a fixed version at // https://github.com/mono/mono/blob/master/mcs/class/corlib/System.Security.Cryptography/PasswordDeriveBytes.cs // But I'm no cryptographer so I might be wrong. // But this seems to work for low values of $hashno and seems to work // with C# implementations. if ($extracount > 0) { $rlen = strlen($extra) - $extracount; if ($rlen >= $cb) { $result = substr($extra, $extracount, $cb); if ($rlen > $cb) { $extracount += $cb; } else { $extra = null; $extracount = 0; } return $result; } $result = substr($extra, $rlen, $rlen); } $current = ""; $clen = 0; $remain = $cb - strlen($result); while ($remain > $clen) { if ($hashno == 0) { $current = sha1($base, true); } else if ($hashno < 1000) { $n = sprintf("%d", $hashno); $tmp = $n . $base; $current .= sha1($tmp, true); } $hashno++; $clen = strlen($current); } // $current now holds at least as many bytes as we need $result .= substr($current, 0, $remain); // Save any left over bytes for any future requests if ($clen > $remain) { $extra = $current; $extracount = $remain; } return $result; } ?>

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