PureBasic

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.

PureBasic

IncludeFile "CkCrypt2.pb"

Procedure ChilkatExample()

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

    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

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

    strToHash.s = "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:
    CkCrypt2::setCkCharset(crypt, "us-ascii")
    ; The EncodingMode property defines the binary encoding (hex, base64, etc.) of the hash returned as an encoded string.
    CkCrypt2::setCkEncodingMode(crypt, "hex")
    CkCrypt2::setCkHashAlgorithm(crypt, "sha256")

    hashValue.s = CkCrypt2::ckHashStringENC(crypt,strToHash)
    Debug CkCrypt2::ckLastErrorText(crypt)
    Debug "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.
    CkCrypt2::setCkCharset(crypt, "hex")
    ; The EncodingMode and HashAlgorithm remain the same..
    hashValue = CkCrypt2::ckHashStringENC(crypt,strToHash)
    Debug CkCrypt2::ckLastErrorText(crypt)
    Debug "hash of 6 hex bytes: " + hashValue

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


    CkCrypt2::ckDispose(crypt)


    ProcedureReturn
EndProcedure