Key Refresh protocol

[naure]

This is the first version of the Key Refresh protocol.

---

• Init keyrefresh module

• Add MessageType and BroadcastTag for keyrefresh.

• Fix test

• keyrefresh: protocol description

• keyrefresh: Remove rid

• keyrefresh: generate key updates for all participants.

• keyrefresh: key updates sum to 0. Store updates.

• keyrefresh: generate, broadcast, and verify proofs. Remove keygen variant.

• keyrefresh: aggregate updates

• keyrefresh: send and receive private updates

• keyrefresh: pass inputs from keygen and auxinfo

• keyrefresh: encrypt and decrypt the private updates

• keyrefresh: verify_with_precommit

• keyrefresh: all checks for KeyrefreshDecommit

[gatoWololo]

It looks like the CI is failing due to formatting differences. You can always run cargo make ci to test this locally! (Assumes you have cargo make installed).

[naure]

Also fixed all linter errors.

I just figured out that the usual warnings from cargo and rust-analyzer don’t work with the specified rust version. I used this command to make it work again:

rustup override set nightly

[naure]

Overall, the code looks good. I just have some minor comments. I will say that I don't think the original paper updated rid with rho for key refresh, but updating rid with rho should not be problematic from a replay standpoint.

Indeed you're right. Should it just keep the old rid instead?

[naure]

The output now keeps the existing rid instead of the new one.