b9ebee1490cc10286780c824a2bfac6bbb961cee fix a couple things to make Elements 22's linter happy (Andrew Poelstra)
Pull request description:
In Elements 22 the linter looks for executable files that don't have a properly-formed shebang. For some reason it wants `/usr/bin/env bash` rather than `/bin/bash`, and also one of our source files was erroneously 755.
ACKs for top commit:
real-or-random:
ACK b9ebee1490cc10286780c824a2bfac6bbb961cee
Tree-SHA512: 00da8fefd67c1882c6cec39dc81ce67ae3f52f902ddf72545e902b8f5bc7cd7c1249bf71027c530245c403a99c86ffbb61a89bc18c27c5ec975f6f653200766c
72713872a8597884918bcf1edbc12f5c969ca680 Add missing static to secp256k1_schnorrsig_sign_internal (Elichai Turkel)
Pull request description:
This function isn't used outside of this module so it should be declared static
ACKs for top commit:
real-or-random:
ACK 72713872a8597884918bcf1edbc12f5c969ca680
jonasnick:
ACK 72713872a8597884918bcf1edbc12f5c969ca680
Tree-SHA512: 6107a2c84c3e11ffd68de22a5288d989a3c71c2ec1ee4827c88f6165fc27ef8339d0f6740928540e8ccd03aff49a2a96149bf698ccebe6d6d8ad6e23e38e8838
adec5a16383f1704d80d7c767b2a65d9221cee08 Add missing null check for ctx and input keys in the public API (Elichai Turkel)
f4edfc758142d6e100ca5d086126bf532b8a7020 Improve consistency for NULL arguments in the public interface (Elichai Turkel)
Pull request description:
I went over the public API and added missing explanations on when a pointer can be null and when it cannot,
and added some missing checks for null ctx and null pubkey pointers.
Open questions IMHO:
1. Can `secp256k1_context_create` return NULL? right now it could return null if you replaced the callbacks at compile time to ones that do return(unlike the default ones which never return).
2. Related to the first, should we document that the callbacks should never return? (in the tests we use returning callbacks but we can violate our own API) right now we say the following:
> After this callback returns, anything may happen, including crashing.
Is this enough to document answer `no` for the first question and just saying that if the callback returned then you violated the API so `secp256k1_context_create` can return NULL even though it is promised not to?
Right now we AFAICT we never check if it returns null
Another nit I'm not sure about is wording `(does nothing if NULL)`/`(ignored if NULL)`/`(can be NULL)`
More missing docs:
1. Documenting the `data` argument to the default nonce functions
ACKs for top commit:
ariard:
ACK adec5a16
jonasnick:
ACK adec5a16383f1704d80d7c767b2a65d9221cee08
Tree-SHA512: 6fe785776b7e451e9e8cae944987f927b1eb2e2d404dfcb1b0ceb0a30bda4ce16469708920269417e5ada09739723a430e270dea1868fe7d12ccd5699dde5976
8f093be374da794b835302bfb81a72e2bdd51d26 musig: use tagged hash for the list of pubkeys to aggregate (Jonas Nick)
a6a768a4bf3a243609e508c492307cb0fe754bda musig: make key agg test vector more precise (Jonas Nick)
Pull request description:
Top commit has no ACKs.
Tree-SHA512: 5369dc5b4039dd4cda2c50282db2882c088b96e1daa5801240f92be1832ed8f29317fdbfc3cab211707155c284a68dc593967f3141703e2544f6b8dc1553e44d
Also add a specific test that fails adaptor sig deserialization because with the
correct size buffer that's not guaranteed anymore with the existing test.
Previously the ECDSA signature had an overflowing s value, which after the sync
with upstream results in a failing VERIFY_CHECK in the inversion function.
However, normally parsed signatures shouldn't contain overflowing s values.
unsigned char foo[4] = "abcd" is not valid C++ because the string
literal "abcd" does not fit into foo due to the terminating NUL
character. This is valid in C, it will just omit the NUL character.
Fixes#962.
Varlen message support for the default sign function comes from recommending
tagged_sha256. sign_custom on the other hand gets the ability to directly sign
message of any length. This also implies signing and verification support for
the empty message (NULL) with msglen 0.
Tests for variable lengths follow in a later commit.
This makes the default sign function easier to use while allowing more granular
control through sign_custom.
Tests for sign_custom follow in a later commit.
This commit adds test coverage including Cirrus scripts, Valgrind
constant time tests for secret data, API tests, nonce function tests,
and test vectors from the spec.
This commit adds the ECDSA adaptor signature APIs:
- Encrypted Signing
Creates an adaptor signature, which includes a proof to verify the adaptor
signature.
- Encryption Verification
Verifies that the adaptor decryption key can be extracted from the adaptor
signature and the completed ECDSA signature.
- Signature Decryption
Derives an ECDSA signature from an adaptor signature and an adaptor decryption
key.
- Key Recovery
Extracts the adaptor decryption key from the complete signature and the adaptor
signature.
This commit adds proving and verification functions for discrete
logarithm equality.
From the spec (https://github.com/discreetlogcontracts/dlcspecs/pull/114):
"As part of the ECDSA adaptor signature a proof of discrete logarithm
equality must be provided. This is a proof that the discrete logarithm of
some X to the standard base G is the same as the discrete logarithm of
some Z to the base Y. This proof can be constructed by using equality
composition on two Sigma protocols proving knowledge of the discrete
logarithm between both pairs of points. In other words the prover proves
knowledge of a such that X = a * G and b such that Z = b * Y and that
a = b. We make the resulting Sigma protocol non-interactive by applying
the Fiat-Shamir transformation with SHA256 as the challenge hash."
This commit adds a nonce function that will be used by default
for ECDSA adaptor signatures.
This nonce function is similar to secp256k1_nonce_function_hardened
except it uses the compressed 33-byte encoding for the pubkey argument.
We need 33 bytes instead of 32 because, unlike with BIP-340, an ECDSA
X-coordinate alone is not sufficient to disambiguate the Y-coordinate.
This will fix the following compile error on macOS
In file included from src/num.h:17,
from src/num_impl.h:14,
from src/bench_whitelist.c:14:
src/num_gmp.h:10:10: fatal error: gmp.h: No such file or directory
