Cryptographic hash functions play a critical role in computer security providing a one-way transformation of sensitive data. Many information-security applications benefit from using hash functions, specifically digital signatures, message authentication codes, and other forms of authentication. The calculation of hash functions such as SHA512, SHA256, MD5 etc is a potential playground for Custom Compute. This is where the ISA flexibility enabled by RISC-V and empowered by the Zk extension, as well as the ability to merge inherently sequential bit manipulations in custom instructions help to improve the performance.