Hope you are doing well and are happy! I'm always interested in Crypto! For the work that I'm doing, we don't use Crypto shipped inside Squeak instead we use the Cryptographic modules available from the OS to do the work. This has a number of really good benefits. First, it eliminates the needed to ship cryptography and comply with the US restrictions and second, it helps to ensure that the modules are as current as possible (they are updated by the OS Provider (Microsoft, Windows, and Linux Provider). This is mainly the reason that I stopped working on the Squeak code. That being said the
www.squeaksource.com repository is registered with the US Government as an opensource repository for holding restricted code. I don't see any reason to not update the code. (Please be advised that I'm not a lawyer and if you or anyone contributes to the repository or uses the code and especially ships a product containing cryptographic code you are responsible to understand and follow the laws that apply in your country).
I might be interested in implementing SHA512. I did the SHA256. What did you have in mind? Is there some way that I can help coordinate our efforts?