Make defer-decryption default

[th4s]

This PR makes defer-decryption default and introduces the necessary config changes.

[themighty1]

LGTM!

As agreed, I pushed a commit with clarifying comments and a name change with the goal of:

• Emphasize that deferred decryption is toggleable.
• I tried to avoid leaking the concept of "deferred" into the Transcript-related type.
  From Transcripts pov there is only data written to it in the online and in the offline phases. I hope this abstraction is correct and I'm not overlooking sth.

[th4s]

lgtm, thank you! Having the inner transcript not know about the concept of deferred decryption makes sense to me.

Seems like some test doesn't like the changes, or randomly fails.

[th4s]

Seems like some test doesn't like the changes, or randomly fails.

Opened an issue for this.

[yuroitaki]

great stuff! just one nit

[sinui0]

I feel we should just remove the defaults entirely. It would be an error to not set one of the recv sizes. It's not much burden on the user to make sure they think about how much data will be communicated.

[sinui0]

Suggested change

#[builder(default = "DEFAULT_MAX_SENT_LIMIT")]

[sinui0]

Suggested change

#[builder(default = "self.default_max_deferred_size()")]

[th4s]

I am not sure. Users will have to dive into our ProtocolConfig. You can no longer just create a ProverConfig with a default ProtocolConfig. Now you have to think about all these traffic sizes and understand what it is and what deferred decryption is. No simple "just-do-the-thing" mode anymore.

What is the advantage of having no defaults?

[sinui0]

Users will have to understand this particular configuration anyhow, unless we find an abstraction in higher level tooling. I recall several people running into transcript limit issues. The defaults we have right now are arbitrary.

The solution to hiding deferred decryption complexity is to change our approach slightly. It's the default, so we can invert the naming:

1. max_sent: Sent data length
2. max_recv: Received data length
3. max_recv_online: The amount of data that needs to be decrypted online.

Assert max_recv_online <= max_recv, the difference is what we decrypt offline.

[th4s]

That sounds good. But then max_recv_online will get a default of 0 and the other two will have no default so that they have to be set by the user, right?

[sinui0]

1 change