(DataFlex) Hash a Hex String

Demonstrates common pitfalls in hashing a hex string..

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoCrypt
    String sStrToHash
    String sHashValue
    String sTemp1

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

    Get Create (RefClass(cComChilkatCrypt2)) To hoCrypt
    If (Not(IsComObjectCreated(hoCrypt))) Begin
        Send CreateComObject of hoCrypt
    End

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

    Move "b08538d832bf" To sStrToHash

    // 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:
    Set ComCharset Of hoCrypt To "us-ascii"
    // The EncodingMode property defines the binary encoding (hex, base64, etc.) of the hash returned as an encoded string.
    Set ComEncodingMode Of hoCrypt To "hex"
    Set ComHashAlgorithm Of hoCrypt To "sha256"

    Get ComHashStringENC Of hoCrypt sStrToHash To sHashValue
    Get ComLastErrorText Of hoCrypt To sTemp1
    Showln sTemp1
    Showln "hash of 12 us-ascii bytes: " sHashValue

    // 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.
    Set ComCharset Of hoCrypt To "hex"
    // The EncodingMode and HashAlgorithm remain the same..
    Get ComHashStringENC Of hoCrypt sStrToHash To sHashValue
    Get ComLastErrorText Of hoCrypt To sTemp1
    Showln sTemp1
    Showln "hash of 6 hex bytes: " sHashValue

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


End_Procedure