Node.js

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.

Node.js

NODEJS_PRELUDE

function chilkatExample() {

    //  This example assumes the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    var crypt = new chilkat.Crypt2();

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

    var 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.Charset = "us-ascii";
    //  The EncodingMode property defines the binary encoding (hex, base64, etc.) of the hash returned as an encoded string.
    crypt.EncodingMode = "hex";
    crypt.HashAlgorithm = "sha256";

    var hashValue = crypt.HashStringENC(strToHash);
    console.log(crypt.LastErrorText);
    console.log("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.Charset = "hex";
    //  The EncodingMode and HashAlgorithm remain the same..
    hashValue = crypt.HashStringENC(strToHash);
    console.log(crypt.LastErrorText);
    console.log("hash of 6 hex bytes: " + hashValue);

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

}

chilkatExample();