Expose CPA primitives about kyber

[mberry]

Hi, I've look through your repo and can't tell what primitives you are needing, which module/s in particular?

Regardless, I'm fine with this, but would put it behind a hazmat feature gate with some usage warning to expose internals.

[tbrezot]

Hey, thank your answer.

I would need the primitives of IND-CPA Kyber that are in reference::indcpa. Namely, indcpa_keypair, indcpa_enc and indcpa_dec.

Sure I agree this should not be exposed by default.

I forked your repo waiting for this change to be made upstream. I would propose a MR but it seems your editor leaves trailing spaces at the end of lines (while mine removes them on save) and that you are not using rustfmt so it is a bit tedious to get clean diffs...

Would you consider sticking to the rustfmt format or indicating how to format your code the way you do (I couldn't find it in your readme)?

Apart from exposing these primitives, I think I have spotted deprecated documentations which refer to KYBER_INDCPA_MSGBYTES when no constant is declared with this name in the crate. As I understood, it should be replaced by KYBER_SYMBYTES.

[tbrezot]

I have exposed the primitives in #36

[tbrezot]

Solved in #36