69b392f3cb musig: move explanation for aggnonce=inf to spec (Jonas Nick)
4824220bb7 musig-spec: describe NonceGen, NonceAgg, Sign,PartialSig{Verify,Agg} (Jonas Nick)
3c122d0780 musig-spec: improve definition of lift_x (Jonas Nick)
e0bb2d7009 musig-spec: improve KeyAgg description (Jonas Nick)
b8f4e75d89 musig-spec: move to doc directory (Jonas Nick)
Pull request description:
Will wait before adding tweaking until #151 is merged.
ACKs for top commit:
robot-dreams:
ACK 69b392f3cb based on:
real-or-random:
ACK 69b392f3cb I haven't looked at every detail but it's certainly ready to be merged as draft spec
Tree-SHA512: e3aa0265a9d7a7648e03ca42575397100edd5af43f0224937af51aa5c77efc451d7938149bdc711f69e24fb9291438453b8cd762affaa1a2e7bcc89f121485df
8088eddc53 musig: add test vector for ordinary (non xonly) tweaking (Elliott Jin)
57a17929fc musig: add ordinary and xonly tweaking to the example (Jonas Nick)
37107361a0 musig: allow ordinary, non-xonly tweaking (Jonas Nick)
c519b46879 musig: add pubkey_get to obtain a full pubkey from a keyagg_cache (Jonas Nick)
Pull request description:
In short, `musig_pubkey_tweak_add` now allows for xonly _and_ "ordinary" tweaking. Also, in order to allow using `ec_pubkey_tweak_add` on the non-xonly aggregate public key, there's a new function `musig_pubkey_get` that allows obtaining it from the `keyagg_cache`.
One alternative would be that instead of adding `musig_pubkey_get`, we could change `pubkey_agg` to output an ordinary (non-xonly) pubkey. Then users of the API who do not need ordinary (BIP32) tweaking would be forced to call `xonly_pubkey_from_pubkey`. And we'd probably want to change the spec. And it would be a bit weird to output a pubkey that can't be directly schnorrsig_verify'd.
Based on #131
ACKs for top commit:
robot-dreams:
ACK 8088eddc53 based on https://github.com/ElementsProject/secp256k1-zkp/pull/151#issuecomment-1005198409 and the following `range-diff`:
Tree-SHA512: a4a0100f0470c870f88a8da27dbcc4684fcc2caabb368d4340e962e08d5ee04634e6289bafa3448dbfd0b5793a3e70de5bd6ddca7a619cc3220ff762d518a8fe
3d7cbafb5f tests: Fix test whose result is implementation-defined (Tim Ruffing)
Pull request description:
A compiler may add struct padding and fe_cmov is not guaranteed to
preserve it.
On the way, we restore the name of the function. It was mistakenly
renamed in 6173839c90 using
"search and replace".
ACKs for top commit:
robot-dreams:
ACK 3d7cbafb5f
sipa:
utACK 3d7cbafb5f
Tree-SHA512: f8bb643d4915e9ce9c4fe45b48a2878f6cf1f29e654be1c150cdf65c6959cf65f8491928cf098da5a01f1d488ba475914905ca96b232abed499eb6ed65e53fb8
77a19750b4 Use xoshiro256++ PRNG instead of RFC6979 in tests (Pieter Wuille)
5f2efe684e secp256k1_testrand_int(2**N) -> secp256k1_testrand_bits(N) (Pieter Wuille)
Pull request description:
Just some easy low-hanging fruit. It's complete overkill to use the RFC6979 RNG for our test randomness. Replace it with a modern non-cryptographic RNG with good properties. It's a few % speedup for me.
Given the internal naming of all these functions to be "testrand", I'm not concerned about the risk of someone using this for something that needs actual cryptographic randomness.
ACKs for top commit:
robot-dreams:
ACK 77a19750b4
real-or-random:
utACK 77a19750b4
Tree-SHA512: 2706f37689e037e84b5df25c98af924c0756e6d59f5f822b23aec5ba381b2d536e0848f134026e2568396427218f1c770f1bb07613d702efb23a84015dc9271d
A compiler may add struct padding and fe_cmov is not guaranteed to
preserve it.
On the way, we improve the identity check such that it covers the
VERIFY struct members.
b4ac1a1d5f ci: Run valgrind/memcheck tasks with 2 CPUs (Tim Ruffing)
e70acab601 ci: Use Cirrus "greedy" flag to use idle CPU time when available (Tim Ruffing)
d07e30176e ci: Update brew on macOS (Tim Ruffing)
22382f0ea0 ci: Test different ecmult window sizes (Tim Ruffing)
26a022a3a0 ci: Remove STATICPRECOMPUTATION (Tim Ruffing)
10461d8bd3 precompute_ecmult: Always compute all tables up to default WINDOW_G (Tim Ruffing)
Pull request description:
ACKs for top commit:
elichai:
utACK b4ac1a1d5f
jonasnick:
ACK b4ac1a1d5f
Tree-SHA512: b283d7b1c72cf87484de1fe98318298698fe9982dc33389eaca62e92318ab0074c183b9799add274f46358032491fee875e5ffb2a76a47f3b07520b850f4c85e
1287786c7a doc: Add comment to top of field_10x26_impl.h (Elliott Jin)
58da5bd589 doc: Fix upper bounds + cleanup in field_5x52_impl.h comment (Elliott Jin)
Pull request description:
When reviewing #816 I noticed the upper bounds in the comment at the top of `field_5x52_impl.h` were off by 1 (see `fe_verify`). This PR fixes the upper bounds and also cleans up the comment along the way.
ACKs for top commit:
real-or-random:
ACK 1287786c7a
Tree-SHA512: 4b7dadc92451ab1ceb5a547a3101ff37f3ffd0645490563f1f3442ea8d6219f100ed914289d22435c4172d190fa1ff52e37e4464132bb3f9bbcc338488227f7b
22d25c8e0a Add another ecmult_multi test (Pieter Wuille)
Pull request description:
ACKs for top commit:
jonasnick:
ACK 22d25c8e0a
Tree-SHA512: e1394fa1708e65a66d4b324cca60dd49c67e37b23b7da2a3ff0db7a2a25c23976cb03b96a8c8584ee81aaec559feb84fb113dff2e2ebf89110ed466a4a6b158b
ac1e36769d musig: turn off multiexponentiation for now (Jonas Nick)
3c79d97bd9 ci: increase timeout for macOS tasks (Jonas Nick)
22c88815c7 musig: replace MuSig(1) with MuSig2 (Jonas Nick)
Pull request description:
The main commit comprises `905 insertions(+), 1253 deletions(-)`. The diff isn't as small as I had hoped, but that's mostly because it was possible to simplify the API quite substantially which required rewriting large parts. Sorry, almost all of the changes are in one big commit which makes the diff very hard to read. Perhaps best to re-review most parts from scratch.
A few key changes:
- Obviously no commitment round. No big session struct and no `verifier` sessions. No `signer` struct.
- There's a new `secnonce` struct that is the output of musig_nonce_gen and derived from a uniformly random session_id32. The derivation can be strengthened by adding whatever session parameters (combined_pk, msg) are available. The nonce function is my ad-hoc construction that allows for these optional inputs. Please have a look at that.
- The secnonce is made invalid after being used in partial_sign.
- Adaptor signatures basically work as before, according to https://github.com/ElementsProject/scriptless-scripts/pull/24 (with the exception that they operate on aggregate instead of partial sigs)
- To avoid making this PR overly complex I did not consider how this implementation interacts with nested-MuSig, sign-to-contract, and antiklepto.
- Testing should be close to complete. There's no reachable line or branch that isn't exercised by the tests.
- [x] ~In the current implementation when a signer sends an invalid nonce (i.e. some garbage that can't be mapped to a group element), it is ignored when combining nonces. Only after receiving the signers partial signature and running `partial_sig_verify` will we notice that the signer misbehaved. The reason for this is that 1) this makes the API simpler and 2) malicious peers don't gain any additional powers because they can always interrupt the protocol by refusing to sign. However, this is up for discussion.~ EDIT: this is not the case anymore since invalid nonces are rejected when they're parsed.
- [x] ~For every partial signature we verify we have to parse the pubnonce (two compressed points), despite having parsed it in `process_nonces` already. This is not great. `process_nonces` could optionally output the array of parsed pubnonces.~ EDIT: fixed by having a dedicated type for nonces.
- [x] ~I left `src/modules/musig/musig.md` unchanged for now. Perhaps we should merge it with the `musig-spec`~ EDIT: musig.md is updated
- [x] partial verification should use multiexp to compute `R1 + b*R2 + c*P`, but this can be done in a separate PR
- [x] renaming wishlist
- pre_session -> keyagg_cache (because there is no session anymore)
- pubkey_combine, nonce_combine, partial_sig_combine -> pubkey_agg, nonce_agg, partial_sig_agg (shorter, matches terminology in musig2)
- musig_session_init -> musig_start (shorter, simpler) or [musig_generate_nonce](https://github.com/ElementsProject/secp256k1-zkp/pull/131#discussion_r654190890) or musig_prepare
- musig_partial_signature to musig_partial_sig (shorter)
- [x] perhaps remove pubnonces and n_pubnonces argument from process_nonces (and then also add a opaque type for the combined nonce?)
- [x] write the `combined_pubkey` into the `pre_session` struct (as suggested [below](https://github.com/ElementsProject/secp256k1-zkp/pull/131#issuecomment-866904975): then 1) session_init and process_nonces don't need a combined_pk argument (and there can't be mix up between tweaked and untweaked keys) and 2) pubkey_tweak doesn't need an input_pubkey and the output_pubkey can be written directly into the pre_session (reducing frustration such as Replace MuSig(1) module with MuSig2 #131 (comment))
- [x] perhaps allow adapting both partial sigs (`partial_sig` struct) and aggregate partial sigs (64 raw bytes) as suggested [below](https://github.com/ElementsProject/secp256k1-zkp/pull/131#issuecomment-867281531).
Based on #120.
ACKs for top commit:
robot-dreams:
ACK ac1e36769d
real-or-random:
ACK ac1e36769d
Tree-SHA512: 916b42811aa5c00649cfb923d2002422c338106a6936a01253ba693015a242f21f7f7b4cce60d5ab5764a129926c6fd6676977c69c9e6e0aedc51b308ac6578d
7dfceceea6 build: Remove #undef hack for ASM in the precomputation programs (Tim Ruffing)
bb36fe9be0 ci: Test `make precomp` (Tim Ruffing)
d94a37a20c build: Remove CC_FOR_BUILD stuff (Tim Ruffing)
ad63bb4c29 build: Prebuild and distribute ecmult_gen table (Tim Ruffing)
ac49361ed0 prealloc: Get rid of manual memory management for prealloc contexts (Tim Ruffing)
6573c08f65 ecmult_gen: Tidy precomputed file and save space (Tim Ruffing)
5eba83f17c ecmult_gen: Precompute tables for all values of ECMULT_GEN_PREC_BITS (Tim Ruffing)
fdb33dd122 refactor: Make PREC_BITS a parameter of ecmult_gen_build_prec_table (Tim Ruffing)
a4875e30a6 refactor: Move default callbacks to util.h (Tim Ruffing)
4c94c55bce doc: Remove obsolete hint for valgrind stack size (Tim Ruffing)
5106226991 exhaustive_tests: Fix with ecmult_gen table with custom generator (Tim Ruffing)
e1a76530db refactor: Make generator a parameter of ecmult_gen_create_prec_table (Tim Ruffing)
9ad09f6911 refactor: Rename program that generates static ecmult_gen table (Tim Ruffing)
8ae18f1ab3 refactor: Rename file that contains static ecmult_gen table (Tim Ruffing)
00d2fa116e ecmult_gen: Make code consistent with comment (Tim Ruffing)
3b0c2185ea ecmult_gen: Simplify ecmult_gen context after making table static (Tim Ruffing)
e43ba02cfc refactor: Decouple table generation and ecmult_gen context (Tim Ruffing)
22dc2c0a0d ecmult_gen: Move table creation to new file and force static prec (Tim Ruffing)
Pull request description:
This resolves#893, resolves#692 (and also resolvesbitcoin/bitcoin#22854).
- [x] Extract table generation to separate function in separate file (to be used by generation script and exhaustive tests)
- [x] Tidy up
- [x] Remove code that deals with non-static tables
- [x] Make functions that need ecmult_gen not depend on signing context
- [x] Rename stuff to make it fit the new structure and consistent with how we hande verification tables (#956)
- [x] Fix exhaustive tests
- [x] Make table generation function take generator as input
- [x] Overwrite the static tables with a table with custom generator in exhaustive tests
- [x] Overhaul script that generates table files
- [x] Make table generation function take PREC_BITS as input (I have some code already, just not yet in this branch)
- [x] Change generation script to generate three tables (for all three values of ECMULT_GEN_PREC_BITS)
- [x] Ship pre-built tables
- [x] Add pregenerated table file to repo
- [x] Remove generation of table file from build process (like in #956)
- [x] Remove left-over stuff (e.g., detecting a compiler running on the build machine) from build system
- [x] Final cleanups (copyright headers, commit, messages, etc.)
- [ ] (separate PR:) Make sure link-time optimization remove corresponding static tables (and code) when no signing/verifcation function is called
- [ ] (separate PR:) Compile precomputation as a separate object file and link it (https://github.com/bitcoin-core/secp256k1/pull/988#issuecomment-977813538)
- [ ] (separate PR:) Document the backwards-compatible API changes made in this PR and in #956.
- [ ] Maybe deprecate the static context
ACKs for top commit:
sipa:
ACK 7dfceceea6
robot-dreams:
ACK 7dfceceea6 (based on range-diff between 56284c7d44c0ed46e636588bfbf6c403b7dfa6c1 and 7dfceceea6)
Tree-SHA512: 6efb3f36f05efe3b79bbd877881fe1409f71fd6488d24c811b2e77d9f053bed78670dd1dcbb42ad780458a51c4ffa36de9cd6567271b22041dc7a122ceb677c5
This was necessary because we used to cross-compile the library but
compile the precomputation programs for the build host. Now it's no
longer necessary and we can cleanly link even the external ASM
(which was the intent of #935).
On the way, remove an obsolete "-I" parameter.
