PHP Extension

Duplicate .NET's Rfc2898DeriveBytes Functionality

See more Encryption Examples

Demonstrates how to duplicate the results produced by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class. PHP Extension

<?php

include("chilkat.php");

// This example assumes Chilkat Crypt2 to have been previously unlocked.
// See Unlock Crypt2 for sample code.

// This example demonstrates how to duplicate the results produced
// by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class.

// For example, here is C# code that transforms a password string into
// bytes that can be used as a secret key for symmetric encryption (such as AES, blowfish, 3DES, etc.)
// 
//     Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes("secret", System.Text.Encoding.UTF8.GetBytes("saltsalt123"), numIterations);
//     byte[] secretKeyBytes = deriveBytes.GetBytes(numBytes);

// (The Rfc2898DeriveBytes computation is really just the PBKDF2 algorithm with SHA-1 hashing.)
// In Chilkat, this is what we do to match...

// First, let's get a test vector with known results.  Both Chilkat AND Microsoft should produce
// the same results.  RFC 6070 has some PBKDF2 HMAC-SHA1 Test Vectors.  Here is one of them:

//      Input:
//        P = "passwordPASSWORDpassword" (24 octets)
//        S = "saltSALTsaltSALTsaltSALTsaltSALTsalt" (36 octets)
//        c = 4096
//        dkLen = 25
// 
//      Output:
//        DK = 3d 2e ec 4f e4 1c 84 9b
//             80 c8 d8 36 62 c0 e4 4a
//             8b 29 1a 96 4c f2 f0 70
//             38                      (25 octets)
// 
// 

$crypt = new CkCrypt2();

$salt = 'saltSALTsaltSALTsaltSALTsaltSALTsalt';
// Given that the salt is really binary data (can be any random bunch of bytes),
// we must pass the exact hex string representation of the salt bytes.
// In this case, we're getting the utf-8 byte representation of our salt string,
// which is identical to the us-ascii byte representation because there are no 8bit chars..
$saltHex = $crypt->encodeString($salt,'utf-8','hex');

// Duplicate the test vector as shown above.
$dkHex = $crypt->pbkdf2('passwordPASSWORDpassword','utf-8','sha1',$saltHex,4096,25 * 8,'hex');
print $dkHex . "\n";

?>