Xbase++

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.

Xbase++

LOCAL oCrypt
LOCAL cStrToHash
LOCAL cHashValue

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

oCrypt := CreateObject("Chilkat.Crypt2")

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

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

cHashValue := oCrypt:HashStringENC(cStrToHash)
? oCrypt:LastErrorText
? "hash of 12 us-ascii bytes: " + cHashValue

//  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.
oCrypt:Charset := "hex"
//  The EncodingMode and HashAlgorithm remain the same..
cHashValue := oCrypt:HashStringENC(cStrToHash)
? oCrypt:LastErrorText
? "hash of 6 hex bytes: " + cHashValue

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

oCrypt:destroy()