Java

Hash a Hex String

See more Encryption Examples

Demonstrates common pitfalls in hashing a hex string..

Note: This example requires Chilkat v9.5.0.70 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example assumes the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        Crypt2 crypt = new Crypt2();

        // We have a hex string to be SHA-256 hashed:  "b08538d832bf"
        // The result we expect to receive is "8a9f04cb1adfbd7f59c5918635f92f6c847e5b15f9828519d2fdbd6ead0918fc"

        String strToHash = "b08538d832bf";

        // How do we get this result?

        // The 1st question to be answered is:  What bytes are getting hashed?
        // There are two possibilities:
        // 1) Hash 12 bytes, namely the us-ascii values for 'b', '0', '8', '5', .... 'b', 'f'
        // or
        // 2) Hash 6 bytes:  0xb0, 0x85, ... 0xbf
        //

        // This is how to hash the 12 us-ascii byte values:
        // The Charset property defines the byte representation of the string passed to the hash algorithm:
        crypt.setCharset("us-ascii");
        // The EncodingMode property defines the binary encoding (hex, base64, etc.) of the hash returned as an encoded string.
        crypt.setEncodingMode("hex");
        crypt.setHashAlgorithm("sha256");

        String hashValue = crypt.hashStringENC(strToHash);
        System.out.println(crypt.getLastErrorText());
        System.out.println("hash of 12 us-ascii bytes: " + hashValue);

        // The result is:  327F2B33A0F0580D09840B0D7CEE54514CA33E9A  (not what we were hoping).

        // -------------------------------------------
        // This is how to hash the 6 bytes
        //
        // "hex" is not an actual character encoding.  It's a special value to be used to tell Chilkat to hex decode
        // the string and pass the decoded bytes to the hash algorithm...
        // Note: This example requires Chilkat v9.5.0.70 or greater for the "hex" Charset to work properly.
        crypt.setCharset("hex");
        // The EncodingMode and HashAlgorithm remain the same..
        hashValue = crypt.hashStringENC(strToHash);
        System.out.println(crypt.getLastErrorText());
        System.out.println("hash of 6 hex bytes: " + hashValue);

        // The result is 8A9F04CB1ADFBD7F59C5918635F92F6C847E5B15F9828519D2FDBD6EAD0918FC (which equals the hash we were expecting)
    }
}