Java

Duplicate .NET's Rfc2898DeriveBytes Functionality

See more Encryption Examples

Demonstrates how to duplicate the results produced by .NET's System.Security.Cryptography.Rfc2898DeriveBytes class. Chilkat2 Java

import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // 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)
        //
        //

        Crypt2 crypt = new Crypt2();

        String 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..
        String saltHex = crypt.encodeString(salt, "utf-8", "hex");

        // Duplicate the test vector as shown above.
        String dkHex = crypt.pbkdf2("passwordPASSWORDpassword", "utf-8", "sha1", saltHex, 4096, 25 * 8, "hex");
        System.out.println(dkHex);
    }
}