Recently, one of my clients got a letter from Bendigo bank mentioning that bank would no longer support MD5 and we need to change from MD5 to SHA-256
Changing MD5 to SHA-256 is not difficult the only tricky part is how to use secure secret key to generate hash.
To generate secure hash we need to Hex Decode the Secure Secret and use it in HMACSHA256 hasher. Hex decoding is independent of the character encoding.
This the proven way that bank needs it.