This commit also explicitly initializes shortpubkey. For some reason, removing
surrounding, unrelated lines results in gcc warnings when configured with
--enable-ctime-tests=no --with-valgrind=no.
d23da6d557 use secp256k1_scalar_verify checks (stratospher)
c7d0454932 add verification for scalars (stratospher)
ad152151b0 update max scalar in scalar_cmov_test and fix schnorrsig_verify exhaustive test (stratospher)
Pull request description:
From #1360. This PR:
1. adds `secp256k1_scalar_verify` to make sure scalars are reduced mod the group order in VERIFY mode
2. uses `secp256k1_scalar_verify` in all the scalar functions except `secp256k1_scalar_clear`, `secp256k1_scalar_reduce_512`, `secp256k1_scalar_mul_512` and `secp256k1_scalar_*_var` functions in `scalar_low_impl.h`
ACKs for top commit:
real-or-random:
utACK d23da6d557
theStack:
Code-review ACK d23da6d557
Tree-SHA512: a371b319d948198c4038d35c9ea58f4b94de4dc312215e2b78a323c2acd4ae1355d97935c558b388774832d6d0058b97ff8ca50c3aab40b9ede5307760d0a505
The first byte provided to secp256k1_bppp_parse_one_of_points is allowed to be
0, 1, 2, or 3 since it encodes the Y coordinate of two points. In a previous fix
we wrongly assumed it can only be 2 or 3.
The test is supposed to create an invalid sign byte. Before this PR,
the generated sign byte could in fact be valid due to an overflow.
Co-authored-by: Jonas Nick <jonasd.nick@gmail.com>
- `secp256k1_scalar_set_int` in scalar_low uses input mod EXHAUSTIVE_TEST_ORDER
- directly store s in sig64 without reducing it mod the group order for testing
When configured with `--disable-module-ecdh --enable-module-recovery`, then
`./tests 64 81af32fd7ab8c9cbc2e62a689f642106` fails with
```
src/modules/ellswift/tests_impl.h:396: test condition failed: secp256k1_memcmp_var(share32_bad, share32a, 32) != 0
```
This tests verifies that changing the `party` bit of the
`secp256k1_ellswift_xdh` function results in a different share. However, that's
not the case when the secret keys of both parties are the same and this is
actually what happens in the observed test failure. The keys can be equal in
this test case because they are created by the `random_scalar_order_test`
function whose output is not uniformly random (it's biased towards 0).
This commit restores the assummption that the secret keys differ.
The scheme implemented is described below, and largely follows the paper
"SwiftEC: Shallue–van de Woestijne Indifferentiable Function To Elliptic Curves",
by Chavez-Saab, Rodriguez-Henriquez, and Tibouchi
(https://eprint.iacr.org/2022/759).
A new 64-byte public key format is introduced, with the property that *every*
64-byte array is an encoding for a non-infinite curve point. Each curve point
has roughly 2^256 distinct encodings. This permits disguising public keys as
uniformly random bytes.
The new API functions:
* secp256k1_ellswift_encode: convert a normal public key to an ellswift 64-byte
public key, using additional entropy to pick among the many possible
encodings.
* secp256k1_ellswift_decode: convert an ellswift 64-byte public key to a normal
public key.
* secp256k1_ellswift_create: a faster and safer equivalent to calling
secp256k1_ec_pubkey_create + secp256k1_ellswift_encode.
* secp256k1_ellswift_xdh: x-only ECDH directly on ellswift 64-byte public keys,
where the key encodings are fed to the hash function.
The scheme itself is documented in secp256k1_ellswift.h.
f3126fdfec norm arg: remove prove edge tests which are now covered by vectors (Jonas Nick)
847ed9ecb2 norm arg: add verification to prove vectors (Jonas Nick)
cf797ed2a4 norm arg: add prove test vectors (Jonas Nick)
095c1e749c norm arg: add prove_const to tests (Jonas Nick)
bf7bf8a64f norm arg: split norm_arg_zero into prove_edge and verify_zero_len (Jonas Nick)
a70c4d4a8a norm arg: add test vector for |n| = 0 (Jonas Nick)
f5e4b16f0f norm arg: add test vector for sign bit malleability (Jonas Nick)
c0de361fc5 norm arg: allow X and R to be the point at infinity (Jonas Nick)
f22834f202 norm arg: add verify vector for n = [0], l = [0] (Jonas Nick)
d8e7f3763b musig: move ge_{serialize,parse}_ext to module-independent file (Jonas Nick)
Pull request description:
ACKs for top commit:
Liam-Eagen:
ACK f3126fd
Tree-SHA512: 1aad86521fce74435beabe7690c7fcc38ad9ae7a884ddcab69ef825b573433f700723a7672d29df1b4465bc33d5957b6a46f657f988cfd2cc73fa94a3472357d
8e142ca410 Move `SECP256K1_INLINE` macro definition out from `include/secp256k1.h` (Hennadii Stepanov)
77445898a5 Remove `SECP256K1_INLINE` usage from examples (Hennadii Stepanov)
Pull request description:
From [IRC](https://gnusha.org/secp256k1/2023-01-31.log):
> 06:29 \< hebasto\> What are reasons to define the `SECP256K1_INLINE` macro in user's `include/secp256k1.h` header, while it is used internally only?
> 06:32 \< hebasto\> I mean, any other (or a new dedicated) header in `src` looks more appropriate, no?
> 06:35 \< sipa\> I think it may just predate any "utility" internal headers.
> 06:42 \< sipa\> I think it makes sense to move it to util.h
Pros:
- it is a step in direction to better organized headers (in context of #924, #1039)
Cons:
- code duplication for `SECP256K1_GNUC_PREREQ` macro
ACKs for top commit:
sipa:
utACK 8e142ca410
real-or-random:
utACK 8e142ca410
Tree-SHA512: 180e0ba7c2ef242b765f20698b67d06c492b7b70866c21db27c18d8b2e85c3e11f86c6cb99ffa88bbd23891ce3ee8a24bc528f2c91167ec2fddc167463f78eac
