I tried to obtain Checksum from hash string using CSHA256.cls class.
for example:
hash = "238dbd3bd53ee4c53c505ca2b56e1756e622aa0c"
duoblSHA256 = SHA256Hash.SHA256(SHA256Hash.SHA256(hash)
checksum = Mid$(duoblSHA256, 1, 4) Take the first 4 bytes
checksum data =727a41f1