Further changes after making tables static

real-or-random commented at 6:13 pm on January 17, 2022: contributor

More things to improve after #988:

Compile precomputation as a separate object file and link it (solved by #1042)
Speed up secp256k1_ecmult_gen_context_build at context creation. It currently computes fixed values which could be made static (open PR: #1120)
Document (or set by default) build options to remove unused static tables (and code) when no signing/verification function is called (something like --disable-shared CFLAGS="-fdata-sections -ffunction-sections -O2 -g" LDFLAGS="-Wl,--gc-sections")
Document the backwards-compatible API changes made in #988 and in #956: All contexts except the no_precomp context are now effectively signing contexts. The no_precomp context is effectively a verification context., and name is misleading as no context uses dynamic precompuation now. The reason why no_precomp is different is that it’s impossible to re-randomize it.
Decide what to do with the no_precomp context: Possibilities include: renaming it, deprecating it (its main user rust-secp256k1 won’t like this), and/or promote it a full signing context, maybe with a verbose name such as “global-context-less-secure” in the spirit of what rust-secp256k1 is doing.

real-or-random cross-referenced this on Jan 19, 2022 from issue Add serde impl for KeyPair by elsirion

real-or-random cross-referenced this on Feb 1, 2022 from issue Context randomization tracking issue by apoelstra

real-or-random commented at 12:14 pm on February 2, 2022: contributor

* [ ]  Decide what to do with the `no_precomp` context: Possibilities include: renaming it, deprecating it (its main user rust-secp256k1 won't like this), and/or promote it a full signing context, maybe with a verbose name such as "global-context-less-secure" in the spirit of what rust-secp256k1 is doing.

I suggest we

rename _no_precomp to _builtin (or similar)
keep a deprecated alias _no_precomp
expose the self-tests in the public API

We should get rid of the “signing”/“verification” terminology. But there’s potential for bikeshedding. We could also just call it secp256k1_context_builtin, or secp256k1_context_static, or secp256k1_context_basic which is generic enough that we’ll never have to rename it again, even if we add cpuid/whatever in the future (see #780). A more verbose version will be _no_secret_ops. But ECDH is a secret op but we don’t have blinding… And I don’t mind that people are forced to at least have a glimpse at the docs.

Does this sound good?

As a next step, if desired, we could introduce a variant builtin_secret_ops_less_secure (or similar) which is a “signing” context that cannot be randomized… Not sure if we want this.

real-or-random renamed this:
~~Futher changes after making tables static~~
Further changes after making tables static
on Feb 8, 2022

jonasnick commented at 3:01 pm on February 22, 2022: contributor

I suggest we

rename _no_precomp to _builtin (or similar)

keep a deprecated alias _no_precomp

expose the self-tests in the public API

Concept ACK

I’m not aware of the full scope of the context redesign discussions, but it seems like people find the no_precomp context useful. You mentioned the name secp256k1_context_static in PM, which I prefer over the mentioned alternatives.

real-or-random cross-referenced this on Jul 5, 2022 from issue ecmult_gen: Skip RNG when creating blinding if no seed is available by real-or-random

real-or-random referenced this in commit 63a3565e97 on Jul 7, 2022

real-or-random added the label documentation on Jan 5, 2023

real-or-random added the label build on Jan 5, 2023

real-or-random added this to the milestone 0.3.1 (or 0.4.0) on Mar 8, 2023

real-or-random removed this from the milestone 0.3.1 (or 0.4.0) on Mar 8, 2023

real-or-random added this to the milestone stable release (1.0.0-rc.1) on Mar 8, 2023

Further changes after making tables static #1065