Add the public participant-facing ChillDKG API to
include/secp256k1_chilldkg.h and the CertEq sub-protocol, completing
the participant side of the protocol (bip-frost-dkg v0.3.0-dev,
reference pinned at a91896883f85b159415ecf298d5e844879af112d).
New module files:
- certeq.h / certeq_impl.h: CertEq sub-protocol. Participants sign
pad33("BIP DKG/certeq message") || u32be(i) || eq_input with plain
BIP0340-tagged Schnorr signatures under their host key
(certeq_participant_step); verification is per-index against the
x-only hostpubkeys[i][1:33] exactly as the reference
(certeq_verify). The coordinator side reuses certeq_verify in
Phase 4.
Public API (all no-malloc, caller-allocated buffers, outputs zeroed on
failure, secret paths cleared):
- secp256k1_chilldkg_hostpubkey_gen: plain compressed host pubkey
generation; rejects zero / >= group order seckeys.
- secp256k1_chilldkg_params_hash: validates session params (participant
and threshold ranges, strictly compressed non-infinity pubkeys, no
duplicates) and computes TH("BIP DKG/params_hash", u32be(t) ||
hostpubkeys).
- Message-length helpers so callers can size buffers:
participant_msg1_len (33t+32n+97), coordinator_msg1_len
(162n+33(t-1)), participant_msg2_len (64), coordinator_msg2_len
(64n), recovery_data_len (4+33t+162n).
- secp256k1_chilldkg_participant_step1: full EncPedPop step1 with
seed=deckey=hostseckey; rejects zero randomness and hostseckeys not
matching the claimed hostpubkey (input errors, not protocol faults).
- secp256k1_chilldkg_participant_step2: parses and verifies cmsg1 via
the Phase 2 encpedpop/simplpedpop participant path, computes the
tweaked secshare/pubshares/threshold pubkey, appends enc_secshares
to eq_input (matching the reference for recovery consistency), and
emits the 64-byte CertEq signature.
- secp256k1_chilldkg_participant_finalize: re-verifies all n CertEq
signatures in the certificate, then outputs the 32-byte secshare,
33-byte threshold pubkey, n pubshares and the self-delimiting
recovery data (eq_input || cert).
Blame reporting without exceptions: public enum
secp256k1_chilldkg_fault (OK / FAULTY_COORDINATOR /
FAULTY_PARTICIPANT / FAULTY_PARTICIPANT_OR_COORDINATOR /
UNKNOWN_FAULTY_PARTICIPANT_OR_COORDINATOR / INVALID_INPUT) plus an out
fault_index, mapping the reference's exception taxonomy:
- hostseckey invalid/mismatch -> INVALID_INPUT (HostSeckeyError),
- cmsg1 scalar overflow/parse -> FAULTY_COORDINATOR (MsgParseError),
- pubnonce/commitment/PoP faults -> FAULTY_PARTICIPANT_OR_COORDINATOR(i),
- share-vs-pubshare mismatch -> UNKNOWN with fault_index = UINT32_MAX,
- certificate signature failure -> FAULTY_COORDINATOR (documented
deviation: fault_index carries the failing signature index as
diagnostic info; the reference discards it).
Enum-returning functions use a local CHILLDKG_ARG_CHECK that fires the
illegal-argument callback and returns INVALID_INPUT (ARG_CHECK would
return 0 = OK).
Opaque state objects with magic-validated save/load (frost idiom):
participant_state1 (4306 bytes, no secrets) and participant_state2
(21073 bytes, contains the secshare; documented keep-secret/no-copy).
Fixed-size at SECP256K1_CHILLDKG_MAX_PARTICIPANTS = 128.
Also fixes a noverify-build bug: state1_load ran point_load inside
VERIFY_CHECK, which compiles out in noverify builds and left the
commitment uninitialized; now called unconditionally.
tests_impl.h: participant_api_test with full-session reference vectors
(n=3, t=2; coordinator aggregation simulated through the internal
Phase 2 coordinator step and verified byte-identical to the
reference's coordinator_step1): msglen helpers, hostpubkey_gen and
params_hash vectors incl. duplicate/invalid/infinity rejection,
byte-exact pmsg1/cmsg1/CertEq sigs/secshare/thresh_pk/pubshares/
recovery, blame cases (tampered enc_secshare -> UNKNOWN, invalid
pubnonce -> FAULTY_PARTICIPANT_OR_COORDINATOR(1), overflowing
enc_secshare -> FAULTY_COORDINATOR, corrupted cert sig ->
FAULTY_COORDINATOR with fault_index and zeroed outputs), NULL-arg
misuse and bad-magic state rejection.
Verified: make check 3/3 (incl. noverify); CMake ctest 363/363;
make distdir includes all new files.
1605b02f cd49c57e 453949ab 57315a69 97de5120 c5da3bde 99ab4a10 d071aa56 1d146ac3 322d0a43 c7a7f732 ac561601 dfe042fe 3019186a 95e68158 10f546a2 c0a2aba0 ' into temp-merge-1811
c8206b1c b6c2a3cd e7f7083b be5e4f02 5c751833 540fec8a aa2a39c1 8d445730 f9a944ff 2d9137ce 4721e077 471e3a13 ebb35882 1a53f496 c7a52400 ' into temp-merge-1809
c8206b1c b6c2a3cd e7f7083b be5e4f02 5c751833 540fec8a aa2a39c1 8d445730 f9a944ff 2d9137ce 4721e077 471e3a13 ebb35882 1a53f496 c7a52400 ' into temp-merge-1809
libsecp256k1-zkp
A fork of libsecp256k1 with support for advanced and experimental features
Added features:
- Experimental module for ECDSA adaptor signatures.
- Experimental module for ECDSA sign-to-contract.
- Experimental modules for Confidential Assets (Pedersen commitments, range proofs, and surjection proofs).
- Experimental module for address whitelisting.
- Experimental module for Schnorr signature half-aggregation.
- Experimental module for FROST (BIP 445).
Experimental features are made available for testing and review by the community. The APIs of these features should not be considered stable.
Build steps
Obtaining and verifying
The git tag for each release (e.g. v0.6.0) is GPG-signed by one of the maintainers.
For a fully verified build of this project, it is recommended to obtain this repository
via git, obtain the GPG keys of the signing maintainer(s), and then verify the release
tag's signature using git.
This can be done with the following steps:
- Obtain the GPG keys listed in SECURITY.md.
- If possible, cross-reference these key IDs with another source controlled by its owner (e.g. social media, personal website). This is to mitigate the unlikely case that incorrect content is being presented by this repository.
- Clone the repository:
git clone https://github.com/bitcoin-core/secp256k1 - Check out the latest release tag, e.g.
git checkout v0.7.1 - Use git to verify the GPG signature:
% git tag -v v0.7.1 | grep -C 3 'Good signature' gpg: Signature made Mon 26 Jan 2026 07:42:46 PM UTC gpg: using RSA key 2840EAABF4BC9F0FFD716AFAFBAFCC46DE2D3FE2 gpg: Good signature from "Pieter Wuille <pieter@wuille.net>" [unknown] gpg: aka "Pieter Wuille <pieter.wuille@gmail.com>" [full] gpg: aka "[jpeg image of size 5996]" [undefined] gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: 133E AC17 9436 F14A 5CF1 B794 860F EB80 4E66 9320 Subkey fingerprint: 2840 EAAB F4BC 9F0F FD71 6AFA FBAF CC46 DE2D 3FE2
Building with Autotools
$ ./autogen.sh # Generate a ./configure script
$ ./configure # Generate a build system
$ make # Run the actual build process
$ make check # Run the test suite
$ sudo make install # Install the library into the system (optional)
To compile optional modules (such as Schnorr signatures), you need to run ./configure with additional flags (such as --enable-module-schnorrsig). Run ./configure --help to see the full list of available flags. For experimental modules, you will also need --enable-experimental as well as a flag for each individual module, e.g. --enable-module-rangeproof.
Building with CMake
To maintain a pristine source tree, CMake encourages to perform an out-of-source build by using a separate dedicated build tree.
Building on POSIX systems
$ cmake -B build # Generate a build system in subdirectory "build"
$ cmake --build build # Run the actual build process
$ ctest --test-dir build # Run the test suite
$ sudo cmake --install build # Install the library into the system (optional)
To compile optional modules (such as Schnorr signatures), you need to run cmake with additional flags (such as -DSECP256K1_ENABLE_MODULE_SCHNORRSIG=ON). Run cmake -B build -LH or ccmake -B build to see the full list of available flags.
Cross compiling
To alleviate issues with cross compiling, preconfigured toolchain files are available in the cmake directory.
For example, to cross compile for Windows:
$ cmake -B build -DCMAKE_TOOLCHAIN_FILE=cmake/x86_64-w64-mingw32.toolchain.cmake
To cross compile for Android with NDK (using NDK's toolchain file, and assuming the ANDROID_NDK_ROOT environment variable has been set):
$ cmake -B build -DCMAKE_TOOLCHAIN_FILE="${ANDROID_NDK_ROOT}/build/cmake/android.toolchain.cmake" -DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=28
Building on Windows
The following example assumes Visual Studio 2022. Using clang-cl is recommended.
In "Developer Command Prompt for VS 2022":
>cmake -B build -T ClangCL
>cmake --build build --config RelWithDebInfo
Usage examples
Usage examples can be found in the examples directory. To compile them you need to configure with --enable-examples.
- ECDSA example
- Schnorr signatures example
- Deriving a shared secret (ECDH) example
- ElligatorSwift key exchange example
- MuSig2 Schnorr multi-signatures example
To compile the examples, make sure the corresponding modules are enabled.
Benchmark
If configured with --enable-benchmark (which is the default), binaries for benchmarking the libsecp256k1-zkp functions will be present in the root directory after the build.
To print the benchmark result to the command line:
$ ./bench_name
To create a CSV file for the benchmark result :
$ ./bench_name | sed '2d;s/ \{1,\}//g' > bench_name.csv
Reporting a vulnerability
See SECURITY.md
Contributing to libsecp256k1
See CONTRIBUTING.md