kyber Cross-platform compatibility

This PR resolves #494 and resolves #492

I tested the code on a 32-bit Ubuntu VM and tests run smoothly now. It also adds a new step on the CI to run the tests on Alpine Linux x86.

Mar 16 '24 18:03 matteosz

🔒 Could not start CI tests due to missing safe PR label. Please contact a DEDIS maintainer.

Mar 16 '24 18:03 github-actions[bot]

What did you decide regarding putting this only in a v4, like discussed in the PRs you cite? Did you suppose that, because it panics anyway on a 32-bit architecture, it doesn't matter? Please comment this at least in this PR.

I also strongly suggest to start a CHANGELOG.md. I try to put mine in the following format:

https://keepachangelog.com/en/1.1.0/

For all the very nice PRs you're currently doing on kyber, there should be at least one line in the CHANGELOG.md

PS: For small projects, I put the CHANGELOG in the README.md. But for projects like kyber, it deserves its own file.

Mar 18 '24 07:03 ineiti

Overall, it doesn't make sense that "just using explicitly int64 instead of int" should solve the 32-bit issue unless we're actually doing something that is assuming a int64 somewhere on a int. It'd be more interesting to bissect on these changes to find the exact culprit and fix it there rather than just use int64 everywhere.

From what I understand, protobuf is complaining that detected a 32bit machine, please use either int64 or int32. So, yes, changing everything to int32 or int64 will actually solve this problem :)

The other problem it solves, for which there is not est, is hashing an int: once as int32 on 32-bit machines, and once as int64 on 64-bit machines, which would give two different results in the hash.