e82144edfb7673d9a5eeb2b556d08be5223835ac Fixup skew before global Z fixup (Peter Dettman)
40b624c90bff7a40aa28c4d942b0382c300386b8 Add tests for _gej_cmov (Peter Dettman)
8c13a9bfe16c426c082b8df401098c02db53c9a0 ECDH skews by 0 or 1 (Peter Dettman)
15150994333c872a20a1902aa01e1a60dbb1393d Simpler and faster ecdh skew fixup (Peter Dettman)
Pull request description:
This PR adds a `_gej_cmov` method, with accompanying tests, and uses it to simplify the skew fixup at the end of `_ecmult_const`.
In the existing code, `_wnaf_const` chooses a skew of either 1 or 2, and `_ecmult_const` needs a call to `_ge_set_gej` (which does an expensive field inversion internally) and some overly-complicated conversions to/from `_ge_storage` so that `_ge_storage_cmov` can be used to select what value to add for the fixup.
This PR uses a simpler scheme where `_wnaf_const` chooses a skew of 0 or 1 and no longer needs special handling for scalars with value negative one. A new `_gej_cmov` method is used at the end of `_ecmult_const` for const-time optional addition to adjust the final result for the skew. Finally, the skew fixup is moved to before the global-Z adjustment, and the precomputed table entries (for 1P, λ(1P)) are used for the skew fixup, saving a field multiply and ensuring the fixup is done on the same isomorphism as the ladder.
The resulting `_wnaf_const` and `_ecmult_const` are shorter and simpler, and the ECDH benchmark is around 5% faster (64bit, i7).
Edit: Updated description once the final scope was clear.
ACKs for top commit:
apoelstra:
ACK e82144ed
sipa:
ACK e82144edfb7673d9a5eeb2b556d08be5223835ac
real-or-random:
ACK e82144edfb7673d9a5eeb2b556d08be5223835ac
Tree-SHA512: 10d6770f4ef4f8d0c78abbf58d643f25f5daef68896643af0a3f7f877414e23356724b6f20af2027316a4353a35b8cb0a7851e057a3f6483897df02bf033a8a2
3d7cbafb5fd7f152fc47dc907af5df03150accc0 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 6173839c90553385171d560be8a17cbe167e3bef using
"search and replace".
ACKs for top commit:
robot-dreams:
ACK 3d7cbafb5fd7f152fc47dc907af5df03150accc0
sipa:
utACK 3d7cbafb5fd7f152fc47dc907af5df03150accc0
Tree-SHA512: f8bb643d4915e9ce9c4fe45b48a2878f6cf1f29e654be1c150cdf65c6959cf65f8491928cf098da5a01f1d488ba475914905ca96b232abed499eb6ed65e53fb8
77a19750b46916b93bb6a08837c26f585bd940fa Use xoshiro256++ PRNG instead of RFC6979 in tests (Pieter Wuille)
5f2efe684ecca8f767f98ee0ace813103cc88ade 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 77a19750b46916b93bb6a08837c26f585bd940fa
real-or-random:
utACK 77a19750b46916b93bb6a08837c26f585bd940fa
Tree-SHA512: 2706f37689e037e84b5df25c98af924c0756e6d59f5f822b23aec5ba381b2d536e0848f134026e2568396427218f1c770f1bb07613d702efb23a84015dc9271d
3ed0d02bf7690c68ba3ba74da765614809352049 doc: add CHANGELOG template (Jonas Nick)
6f42dc16c8483ff4c5f34cfc3aeae794ca2c660d doc: add release_process.md (Jonas Nick)
0bd3e4243caa3c000e6afe3ea5533b97565557c4 build: set library version to 0.0.0 explicitly (Jonas Nick)
b4b02fd8c4276779f115af5985508f54ef9e51be build: change libsecp version from 0.1 to 0.1.0-pre (Jonas Nick)
Pull request description:
This is an attempt at a simple release process. Fixes#856. To keep it simple, there is no concept of release candidates for now.
The release version is determined by semantic versioning of the API. Since it does not seem to be a lot of work, it is proper to also version the ABI with the libtool versioning system. This versioning scheme (semver API, libtool versioning ABI) follows the suggestion in the [autotools mythbusters](https://autotools.io/libtool/version.html).
Experimental modules are a bit of a headache, as expected. This release process suggests to treat any change in experimental modules as backwards compatible. That way, users of stable modules are not bothered by frequent non-backwards compatible releases. But a downside is that one must not use experimental modules in shared libraries (which should be mentioned in the README?). It would be nice if we could make the schnorrsig module stable in the not too distant future (see also #817).
ACKs for top commit:
apoelstra:
utACK 3ed0d02bf7690c68ba3ba74da765614809352049
elichai:
ACK 3ed0d02bf7690c68ba3ba74da765614809352049
sipa:
ACK 3ed0d02bf7690c68ba3ba74da765614809352049
real-or-random:
ACK 3ed0d02bf7690c68ba3ba74da765614809352049
Tree-SHA512: 25a04335a9579e16de48d378b93a9c6a248529f67f7c436680fa2d495192132743ce016c547aa9718cdcc7fe932de31dd7594f49052e8bd85572a84264f2dbee
05e049b73c69002f498c3c9c21555fd91f95ccac ecmult: move `_ecmult_odd_multiples_table_globalz_windowa` (siv2r)
Pull request description:
Fixes#1035
**Changes:**
- move `secp256k1_ecmult_odd_multiples_table_globalz_windowa` function from ecmult to ecmult_const
- remove outdated comment
ACKs for top commit:
robot-dreams:
utACK 05e049b73c69002f498c3c9c21555fd91f95ccac (`diff` between removed and added lines is exactly as expected)
real-or-random:
utACK 05e049b73c69002f498c3c9c21555fd91f95ccac
Tree-SHA512: 3fad4e93c641b642e84f4bbafcb8083d3e63b0523009fe0edcb2c1ebe1571d822320451289c651403ed1dc033ec6a7a3e8c3c56ad93d81bb1590cf9ff15a3b34
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.
b4ac1a1d5f4d51b9836ac310b78bc9d4256580c2 ci: Run valgrind/memcheck tasks with 2 CPUs (Tim Ruffing)
e70acab601aecf3c5a8affb5a4dce5612b298964 ci: Use Cirrus "greedy" flag to use idle CPU time when available (Tim Ruffing)
d07e30176e084334081fa53be81e75c064375f36 ci: Update brew on macOS (Tim Ruffing)
22382f0ea0e234242e248720b9d1d171cb2de0f8 ci: Test different ecmult window sizes (Tim Ruffing)
26a022a3a0e3fceb1cd2e882e1476c950cabc2e8 ci: Remove STATICPRECOMPUTATION (Tim Ruffing)
10461d8bd3ce3ee8ca443ccad20915217ee74397 precompute_ecmult: Always compute all tables up to default WINDOW_G (Tim Ruffing)
Pull request description:
ACKs for top commit:
elichai:
utACK b4ac1a1d5f4d51b9836ac310b78bc9d4256580c2
jonasnick:
ACK b4ac1a1d5f4d51b9836ac310b78bc9d4256580c2
Tree-SHA512: b283d7b1c72cf87484de1fe98318298698fe9982dc33389eaca62e92318ab0074c183b9799add274f46358032491fee875e5ffb2a76a47f3b07520b850f4c85e
1287786c7a97eff520ffbd6b0d8b2f99dbfc6371 doc: Add comment to top of field_10x26_impl.h (Elliott Jin)
58da5bd589f61b0e0e9b58388ee3e0da8a2c3c3a 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 1287786c7a97eff520ffbd6b0d8b2f99dbfc6371
Tree-SHA512: 4b7dadc92451ab1ceb5a547a3101ff37f3ffd0645490563f1f3442ea8d6219f100ed914289d22435c4172d190fa1ff52e37e4464132bb3f9bbcc338488227f7b
22d25c8e0ab1d24f0f4a80fe016cbd71cd889866 Add another ecmult_multi test (Pieter Wuille)
Pull request description:
ACKs for top commit:
jonasnick:
ACK 22d25c8e0ab1d24f0f4a80fe016cbd71cd889866
Tree-SHA512: e1394fa1708e65a66d4b324cca60dd49c67e37b23b7da2a3ff0db7a2a25c23976cb03b96a8c8584ee81aaec559feb84fb113dff2e2ebf89110ed466a4a6b158b
The preinstalled brew is very old and tries to download prebuilt bottles
from a server which is no longer available. Because that will fail, brew
falls back to building our dependencies (e.g., autotools) from source,
which takes very long.
This commit makes sure that brew is updated before we start the build.
We also need to remove the `--shallow` argument from `brew tap`. It
doesn't exist in recent brew versions.
515e7953cab4eb3be063fa3991e4e0663d3f04ae Improve checks at top of _fe_negate methods (Peter Dettman)
Pull request description:
In theory we could have a single static assertion that would ensure all of these are always true (for any magnitude up to the limit), but I think this small redundancy is clearer.
ACKs for top commit:
sipa:
utACK 515e7953cab4eb3be063fa3991e4e0663d3f04ae
real-or-random:
ACK 515e7953cab4eb3be063fa3991e4e0663d3f04ae bounds hold by inspection and by robot-dreams's script
Tree-SHA512: c33e47e186b37ca0b4e8d23712f8e5ab0c113024a0229fc6ce63b8cbad21bddbecc0c50029721a1fb3376b2d1da678c1ddb69c5ae971d84ddb7993c755867da4
ac1e36769dda3964f7294319ecb06fb5c414938d musig: turn off multiexponentiation for now (Jonas Nick)
3c79d97bd92ec22cc204ff5a08c9b0e5adda12e6 ci: increase timeout for macOS tasks (Jonas Nick)
22c88815c76e6edb23baf9401f820e1a944c3ecf 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 ac1e36769dda3964f7294319ecb06fb5c414938d
real-or-random:
ACK ac1e36769dda3964f7294319ecb06fb5c414938d
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e05da9e480de34129a170510a311abb204eefeb3 Fix c++ build (Pieter Wuille)
c45386d994b48f44009c139c7351a521261e8363 Cleanup preprocessor indentation in precompute{,d}_ecmult{,_gen} (Pieter Wuille)
19d96e15f9b657483c42258568eb70874179d835 Split off .c file from precomputed_ecmult.h (Pieter Wuille)
1a6691adaead20ed55b5400fd4d36f91eb5a3686 Split off .c file from precomputed_ecmult_gen.h (Pieter Wuille)
bb36331412ed68999ac73c871d402e3b03f65700 Simplify precompute_ecmult_print_* (Pieter Wuille)
38cd84a0cb56e031fe43b47e9bdf60349ac9c0a7 Compute ecmult tables at runtime for tests_exhaustive (Pieter Wuille)
e458ec26d61619eafa9fc2b466c1a7b51f794b1f Move ecmult table computation code to separate file (Pieter Wuille)
fc1bf9f15fbe93cb0223c05ee8592ec9bc3070dd Split ecmult table computation and printing (Pieter Wuille)
31feab053b72bfd7ab05347ef7df81b381c92261 Rename function secp256k1_ecmult_gen_{create_prec -> compute}_table (Pieter Wuille)
725370c3f21ad1327b76127784734ffab1f21f97 Rename ecmult_gen_prec -> ecmult_gen_compute_table (Pieter Wuille)
075252c1b7948522455c907ddc97b26f861288eb Rename ecmult_static_pre_g -> precomputed_ecmult (Pieter Wuille)
7cf47f72bc3c2f99e9ac6b050c78b0155a826f74 Rename ecmult_gen_static_prec_table -> precomputed_ecmult_gen (Pieter Wuille)
f95b8106d02f8dd4088609a38647033de217bb5a Rename gen_ecmult_static_pre_g -> precompute_ecmult (Pieter Wuille)
bae77685ebc3ae695e3a50e1c4dbe7aa936ae7a5 Rename gen_ecmult_gen_static_prec_table -> precompute_ecmult_gen (Pieter Wuille)
Pull request description:
This PR implements a number of changes to follow up after merging #988:
* Naming consistency:
* All precomputed table files now have name `precomputed_*.*`
* All source files related to the creation of the precomputed table files have name `precompute_*.*`.
* All source files related to the computation of tables (whether they go in precomputed files or not) have name `*_compute_table.*`.
* Make the tables for exhaustive tests be computed at runtime rather than compile time (this was already the case for ecmult_gen, but not ecmult). This is a preparation for the next point, as the alternative would be to have separate precomputed libraries for the exhaustive tests and other binaries.
* Moves the actual tables to separate `precomputed_*.c` files, which are compiled only once as part of a new `libsecp256k1_precomputed.la`, included where relevant. The corresponding `precomputed_*.h` file are normal source files.
Retry of #1041.
ACKs for top commit:
real-or-random:
ACK e05da9e480de34129a170510a311abb204eefeb3
jonasnick:
ACK e05da9e480de34129a170510a311abb204eefeb3
Tree-SHA512: 71eadd66e30e511b786e910755e0eda53330dfa163b37e33602c3392f7b893569f56d3ca9870e85cbb3de83880fc5aef61ac3d55d759d7395086a69023f13f03
