adding SHA256 so we can represent current ssb messages

[dominictarr]

I suggest adding sha256 format, so that current ssb messages are representable in binary using yamf-hash

[AljoschaMeyer]

Is it okay for you if we postpone this until we know whether ssb will actually need this?

[dominictarr]

okay. obviously I havn't convinced you yet, but I am quite sure that we do actually need this

[dominictarr]

btw, in the very first version, we did use blake2s ... we switched to sha256, because symmetric crypto is fast anyway, and sha256 is much more likely to be in standard libraries etc. Also, sha256 is fine. For a while, they were worried that sha256 was gonna weaken, like sha1 was, and held compettitions to find an heir (which sha3 won, and blake2 close but didn't get chosen) but after doing all that additional research, they understood sha256 better, and realized, actually it was okay.

[AljoschaMeyer]

No worries, I won't block this. I might however sneak in a breaking change and remove blake2, since nobody uses yamf-hash yet. In any case, this should wait until we decided on ssb's needs.

[dominictarr]

Okay, lets wait until we've described upgrade paths and "what is scuttlebutt"