Teradata RDBMS: Generating HMAC SHA256, MD5 and SHA1 Hashes

I’ve come across Teradata User-Defined-Functions (UDF) for generating non key-based hashes (such as MD5 & SHA256) but have yet to come across Teradata HMAC equivalents of these (yet).

That was a good enough reason to work on developing a C/C++ UDF to cover HMAC MD5/SHA256/SHA1 hashing.

Why the Need for Hashing?