This is a backwards-compatible API change: Before this commit, a context
initialized for signing was required to call functions that rely on
ecmult_gen. After this commit, this is no longer necessary because the
static ecmult_gen table is always present. In practice this means that
the corresponding functions will just work instead of calling the
illegal callback when given a context which is not (officially)
initialized for signing.
This is in line with 6815761, which made the analogous change with
respect to ecmult and contexts initialized for signing. But as opposed
to 681571, which removed the ecmult context entirely, we cannot remove
the ecmult_gen context entirely because it is still used for random
blinding. Moreover, since the secp256k1_context_no_precomp context is
const and cannot meaningfully support random blinding, we refrain (for
now) from changing its API, i.e., the illegal callback will still be
called when trying to use ecmult_gen operations with the static
secp256k1_context_no_precomp context.
adec5a1638 Add missing null check for ctx and input keys in the public API (Elichai Turkel)
f4edfc7581 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 adec5a1638
Tree-SHA512: 6fe785776b7e451e9e8cae944987f927b1eb2e2d404dfcb1b0ceb0a30bda4ce16469708920269417e5ada09739723a430e270dea1868fe7d12ccd5699dde5976
1f4dd03838 Typedef (u)int128_t only when they're not provided by the compiler (Tim Ruffing)
e89278f211 Don't use reserved identifiers memczero and benchmark_verify_t (Tim Ruffing)
Pull request description:
As identified in #829 and #833. Fixes#829.
Since we touch this anyway, this commit additionally makes the
identifiers in the benchmark files a little bit more consistent.
This is necessary before we can merge #833. I preferred a separate PR because it makes it easier to see the results of Travis in #833.
ACKs for top commit:
sipa:
utACK 1f4dd03838
jonasnick:
ACK 1f4dd03838
Tree-SHA512: c0ec92798f3c94f3ef6ac69b3f0f39a39257a32be9d9a068832cece1ebe64c89848b70e44652fc397004b8b240883ac4bc0c8f95abbe4ba4b028de120e6734bf
1. using xonly_pubkeys in MuSig for input public keys and the combined
pk. For that to work we need to store whether the MuSig aggregated point
has an even y in the session, may need to negate each signers secret
key and may need to negate each signers public key in
musig_partial_sig_verify.
2. using a tagged hash for the message hash.
3. use !fe_is_odd in place of fe_is_quad_var
If the user passes invalid flags to _context_create, and the default
illegal callback does not abort the program (which is possible), then we
work with the result of malloc(0), which may be undefined behavior. This
violates the promise that a library function won't crash after the
illegal callback has been called.
This commit fixes this issue by returning NULL early in _context_create
in that case.
As identified in #829 and #833. Fixes#829.
Since we touch this anyway, this commit additionally makes the
identifiers in the benchmark files a little bit more consistent.
f431b3f28a valgrind_ctime_test: Add schnorrsig_sign (Jonas Nick)
16ffa9d97c schnorrsig: Add taproot test case (Jonas Nick)
8dfd53ee3f schnorrsig: Add benchmark for sign and verify (Jonas Nick)
4e43520026 schnorrsig: Add BIP-340 compatible signing and verification (Jonas Nick)
7332d2db6b schnorrsig: Add BIP-340 nonce function (Jonas Nick)
7a703fd97d schnorrsig: Init empty experimental module (Jonas Nick)
eabd9bc46a Allow initializing tagged sha256 (Jonas Nick)
6fcb5b845d extrakeys: Add keypair_xonly_tweak_add (Jonas Nick)
58254463f9 extrakeys: Add keypair struct with create, pub and pub_xonly (Jonas Nick)
f0010349b8 Separate helper functions for pubkey_create and seckey_tweak_add (Jonas Nick)
910d9c284c extrakeys: Add xonly_pubkey_tweak_add & xonly_pubkey_tweak_add_test (Jonas Nick)
176bfb1110 Separate helper function for ec_pubkey_tweak_add (Jonas Nick)
4cd2ee474d extrakeys: Add xonly_pubkey with serialize, parse and from_pubkey (Jonas Nick)
47e6618e11 extrakeys: Init empty experimental module (Jonas Nick)
3e08b02e2a Make the secp256k1_declassify argument constant (Jonas Nick)
Pull request description:
This PR implements signing, verification and batch verification as described in [BIP-340](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki) in an experimental module named `schnorrsig`. It includes the test vectors and a benchmarking tool.
This PR also adds a module `extrakeys` that allows [BIP-341](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki)-style key tweaking.
(Adding ChaCha20 as a CSPRNG and batch verification was moved to PR #760).
In order to enable the module run `./configure` with `--enable-experimental --enable-module-schnorrsig`.
Based on apoelstra's work.
ACKs for top commit:
gmaxwell:
ACK f431b3f28a (exactly matches the previous post-fixup version which I have already reviewed and tested)
sipa:
ACK f431b3f28a
real-or-random:
ACK f431b3f28a careful code review
Tree-SHA512: e15e849c7bb65cdc5d7b1d6874678e275a71e4514de9d5432ec1700de3ba92aa9f381915813f4729057af152d90eea26aabb976ed297019c5767e59cf0bbc693
8bc6aeffa9 Add SHA256 selftest (Pieter Wuille)
5e5fb28b4a Use additional system macros to figure out endianness (Pieter Wuille)
Pull request description:
These are all the architecture macros I could find with known endianness. Use those as a fallback when __BYTE_ORDER__ isn't available.
See https://github.com/bitcoin-core/secp256k1/pull/787#issuecomment-673764652
It also adds a SHA256 selftest, so that improperly overriding the endianness detection will be detected at runtime.
ACKs for top commit:
real-or-random:
ACK 8bc6aeffa9 I read the diff, and tested that the self-test passes/fails with/without the correct endianness setting
gmaxwell:
ACK 8bc6aeffa9 looks good and I also ran the tests on MIPS-BE and verified that forcing it to LE makes the runtime test fail.
Tree-SHA512: aca4cebcd0715dcf5b58f5763cb4283af238987f43bd83a650e38e127f348131692b2eed7ae5b2ae96046d9b971fc77c6ab44467689399fe470a605c3458ecc5
