Port the experimental Iceberg module from the benchmark-iceberg tree
(github.com/furszy/benchmark-iceberg, sources/secp256k1-kmp/native/
secp256k1) into this repo.
Iceberg is a threshold scheme that lets a group of parties stand in
for a single MuSig2 (BIP 327) participant: the group produces one
ordinary MuSig2 public nonce and one ordinary MuSig2 partial
signature, so cosigners cannot tell a group is involved and need no
changes. Nonces are derived from a caller-chosen per-session label
(sid32) rather than stored, so no signer holds a secret nonce between
rounds; labels are public but must never be reused. A quorum of 2t-1
members (of whom up to t-1 may be corrupt) is needed in each round,
so the threshold is at most half the group rounded up; combined with
the scheme's other constraints the smallest usable group is 2-of-4.
See doc/iceberg.md and the module header for the full usage notes.
Module layout (src/modules/iceberg/, layered bottom-up, each layer
may only use the ones above it -- that ordering is also the
constant-time story):
- scalar_poly.{h,_impl.h}: secret-carrying polynomial arithmetic,
keeping secrets away from inversions (documented in the header).
- rss.{h,_impl.h}: replicated secret sharing evaluation.
- vpss.{h,_impl.h}: verifiable public shares; variable-time by
design, sees only participant indices and published points.
- keygen_impl.h: distributed key generation producing one share per
member.
- session_impl.h: nonce_gen/nonce_agg and partial_sign/
partial_sig_agg producing plain MuSig2 objects.
- tests_impl.h: 28 tests including the shipped vectors.h vector
suite and dealer known-answer tests.
- bench_impl.h: benchmark definitions (wired in a follow-up commit).
Public headers: include/secp256k1_iceberg.h (installed) and
include/secp256k1_iceberg_dealer.h (in-tree only: a trusted dealer is
not part of the shipped API, but tests, benchmarks and the example
need to deal shares).
Content adaptations relative to the source tree (the only changes to
the ported code): three secp256k1_musig_nonce_process call sites in
tests_impl.h gained a NULL adaptor argument, because this repo's
musig is the zkp variant whose public nonce_process takes an optional
adaptor point. All musig internals the module uses (ge_parse_ext,
ge_serialize_ext, keyaggcoef, aggnonce_load, pubnonce_save,
partial_sig_save, nonce_process_internal) are identical in both
trees, as are all core headers the module touches; nothing else
needed adaptation.
Build wiring mirrors the chilldkg module:
- configure.ac: --enable-module-iceberg (default no, experimental
gate), hard dependency on the musig module with a configure error
if musig is explicitly disabled (musig itself pulls in schnorrsig),
AM_CONDITIONAL(ENABLE_MODULE_ICEBERG), summary line.
- Makefile.am: include src/modules/iceberg/Makefile.am.include under
the conditional.
- src/secp256k1.c: guarded include of modules/iceberg/main_impl.h
after the chilldkg block (musig is included earlier, so its
internals are in scope).
- src/tests.c: module test registration via MAKE_TEST_MODULE(iceberg).
- CMakeLists.txt / src/CMakeLists.txt: SECP256K1_ENABLE_MODULE_ICEBERG
option (OFF) with a dependency check on SECP256K1_ENABLE_MODULE_MUSIG
(placed before the musig block so the force-enable takes effect),
ENABLE_MODULE_ICEBERG=1 compile definition, public header export,
summary line.
Verified: ./configure --enable-experimental --enable-module-iceberg
&& make check passes; ./tests --target=iceberg runs the full module
suite (28/28); CMake build + ctest pass; the musig dependency error
fires correctly in both build systems.
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 module for ChillDKG, distributed key generation for FROST (bip-frost-dkg draft).
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