Squashed 'src/secp256k1/' changes from 2f2ccc46954..0cdc758a563

0cdc758a563 Merge bitcoin-core/secp256k1#1631: release: prepare for 0.6.0
39d5dfd542a release: prepare for 0.6.0
df2eceb2790 build: add ellswift.md and musig.md to release tarball
a306bb7e903 tools: fix check-abi.sh after cmake out locations were changed
145868a84d2 Do not export `secp256k1_musig_nonce_gen_internal`
b161bffb8bf Merge bitcoin-core/secp256k1#1579: Clear sensitive memory without getting optimized out (revival of bitcoin#636)
a38d879a1a6 Merge bitcoin-core/secp256k1#1628: Name public API structs
7d48f5ed02e Merge bitcoin-core/secp256k1#1581: test, ci: Lower default iteration count to 16
694342fdb71 Name public API structs
0f73caf7c62 test, ci: Lower default iteration count to 16
9a8db52f4e9 Merge bitcoin-core/secp256k1#1582: cmake, test: Add `secp256k1_` prefix to test names
765ef53335a Clear _gej instances after point multiplication to avoid potential leaks
349e6ab916b Introduce separate _clear functions for hash module
99cc9fd6d01 Don't rely on memset to set signed integers to 0
97c57f42ba8 Implement various _clear() functions with secp256k1_memclear()
9bb368d1466 Use secp256k1_memclear() to clear stack memory instead of memset()
e3497bbf001 Separate between clearing memory and setting to zero in tests
d79a6ccd43a Separate secp256k1_fe_set_int( . , 0 ) from secp256k1_fe_clear()
1c081262227 Add secp256k1_memclear() for clearing secret data
1464f15c812 Merge bitcoin-core/secp256k1#1625: util: Remove unused (u)int64_t formatting macros
980c08df80a util: Remove unused (u)int64_t formatting macros
9b7c59cbb90 Merge bitcoin-core/secp256k1#1624: ci: Update macOS image
096e3e23f63 ci: Update macOS image
e7d384488e8 Don't clear secrets in pippenger implementation
68b55209f1b Merge bitcoin-core/secp256k1#1619: musig: ctimetests: fix _declassify range for generated nonce points
f0868a9b3d8 Merge bitcoin-core/secp256k1#1595: build: 45839th attempt to fix symbol visibility on Windows
1fae76f50c0 Merge bitcoin-core/secp256k1#1620: Remove unused scratch space from API
8be3839fb2e Remove unused scratch space from API
57eda3ba300 musig: ctimetests: fix _declassify range for generated nonce points
87384f5c0f2 cmake, test: Add `secp256k1_` prefix to test names
e59158b6eb7 Merge bitcoin-core/secp256k1#1553: cmake: Set top-level target output locations
18f9b967c25 Merge bitcoin-core/secp256k1#1616: examples: do not retry generating seckey randomness in musig
5bab8f6d3c4 examples: make key generation doc consistent
e8908221a45 examples: do not retry generating seckey randomness in musig
70b6be1834e extrakeys: improve doc of keypair_create (don't suggest retry)
01b5893389e Merge bitcoin-core/secp256k1#1599: bitcoin#1570 improve examples: remove key generation loop
cd4f84f3ba8 Improve examples/documentation: remove key generation loops
a88aa935063 Merge bitcoin-core/secp256k1#1603: f can never equal -m
3660fe5e2a9 Merge bitcoin-core/secp256k1#1479: Add module "musig" that implements MuSig2 multi-signatures (BIP 327)
168c92011f5 build: allow enabling the musig module in cmake
f411841a46b Add module "musig" that implements MuSig2 multi-signatures (BIP 327)
0be79660f38 util: add constant-time is_zero_array function
c8fbdb1b972 group: add ge_to_bytes_ext and ge_from_bytes_ext
ef7ff03407f f can never equal -m
c232486d84e Revert "cmake: Set `ENVIRONMENT` property for examples on Windows"
26e4a7c2146 cmake: Set top-level target output locations
4c57c7a5a95 Merge bitcoin-core/secp256k1#1554: cmake: Clean up testing code
447334cb06d include: Avoid visibility("default") on Windows
472faaa8ee6 Merge bitcoin-core/secp256k1#1604: doc: fix typos in `secp256k1_ecdsa_{recoverable_,}signature` API description
292310fbb24 doc: fix typos in `secp256k1_ecdsa_{recoverable_,}signature` API description
85e224dd97f group: add ge_to_bytes and ge_from_bytes
7c987ec89e6 cmake: Call `enable_testing()` unconditionally
6aa576515ef cmake: Delete `CTest` module

git-subtree-dir: src/secp256k1
git-subtree-split: 0cdc758a56360bf58a851fe91085a327ec97685a

.cirrus.yml

@@ -22,9 +22,10 @@ env:
   RECOVERY: no
   EXTRAKEYS: no
   SCHNORRSIG: no
+  MUSIG: no
   ELLSWIFT: no
   ### test options
-  SECP256K1_TEST_ITERS:
+  SECP256K1_TEST_ITERS: 64
   BENCH: yes
   SECP256K1_BENCH_ITERS: 2
   CTIMETESTS: yes
@@ -69,6 +70,7 @@ task:
     RECOVERY: yes
     EXTRAKEYS: yes
     SCHNORRSIG: yes
+    MUSIG: yes
     ELLSWIFT: yes
   matrix:
      # Currently only gcc-snapshot, the other compilers are tested on GHA with QEMU
@@ -86,6 +88,7 @@ task:
     RECOVERY: yes
     EXTRAKEYS: yes
     SCHNORRSIG: yes
+    MUSIG: yes
     ELLSWIFT: yes
     WRAPPER_CMD: 'valgrind --error-exitcode=42'
     SECP256K1_TEST_ITERS: 2

.github/workflows/ci.yml

@@ -33,9 +33,10 @@ env:
   RECOVERY: 'no'
   EXTRAKEYS: 'no'
   SCHNORRSIG: 'no'
+  MUSIG: 'no'
   ELLSWIFT: 'no'
   ### test options
-  SECP256K1_TEST_ITERS:
+  SECP256K1_TEST_ITERS: 64
   BENCH: 'yes'
   SECP256K1_BENCH_ITERS: 2
   CTIMETESTS: 'yes'
@@ -72,18 +73,18 @@ jobs:
       matrix:
         configuration:
           - env_vars: { WIDEMUL: 'int64',  RECOVERY: 'yes' }
-          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
           - env_vars: { WIDEMUL: 'int128' }
           - env_vars: { WIDEMUL: 'int128_struct',                                                             ELLSWIFT: 'yes' }
-          - env_vars: { WIDEMUL: 'int128', RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
-          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes' }
+          - env_vars: { WIDEMUL: 'int128', RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes' }
           - env_vars: { WIDEMUL: 'int128', ASM: 'x86_64',                                                     ELLSWIFT: 'yes' }
-          - env_vars: {                    RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes' }
-          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', CPPFLAGS: '-DVERIFY' }
+          - env_vars: {                    RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes' }
+          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', CPPFLAGS: '-DVERIFY' }
           - env_vars: { BUILD: 'distcheck', WITH_VALGRIND: 'no', CTIMETESTS: 'no', BENCH: 'no' }
           - env_vars: { CPPFLAGS: '-DDETERMINISTIC' }
           - env_vars: { CFLAGS: '-O0', CTIMETESTS: 'no' }
-          - env_vars: { CFLAGS: '-O1',     RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { CFLAGS: '-O1',     RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
           - env_vars: { ECMULTGENKB: 2, ECMULTWINDOW: 2 }
           - env_vars: { ECMULTGENKB: 86, ECMULTWINDOW: 4 }
         cc:
@@ -142,6 +143,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CC: ${{ matrix.cc }}
 
@@ -187,6 +189,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
 
@@ -239,6 +242,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
 
@@ -285,6 +289,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
 
@@ -341,6 +346,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
 
@@ -394,6 +400,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
       SECP256K1_TEST_ITERS: 2
@@ -446,6 +453,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
       CFLAGS: '-fsanitize=undefined,address -g'
@@ -511,6 +519,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CC: 'clang'
       SECP256K1_TEST_ITERS: 32
@@ -558,6 +567,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
       CTIMETESTS: 'no'
 
@@ -602,9 +612,9 @@ jobs:
         if: ${{ always() }}
 
   x86_64-macos-native:
-    name: "x86_64: macOS Monterey, Valgrind"
+    name: "x86_64: macOS Ventura, Valgrind"
     # See: https://github.com/actions/runner-images#available-images.
-    runs-on: macos-12
+    runs-on: macos-13
 
     env:
       CC: 'clang'
@@ -615,15 +625,15 @@ jobs:
       fail-fast: false
       matrix:
         env_vars:
-          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
           - { WIDEMUL: 'int128_struct', ECMULTGENKB: 2, ECMULTWINDOW: 4 }
-          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
           - { WIDEMUL: 'int128', RECOVERY: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CPPFLAGS: '-DVERIFY', CTIMETESTS: 'no' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CPPFLAGS: '-DVERIFY', CTIMETESTS: 'no' }
           - BUILD: 'distcheck'
 
     steps:
@@ -751,14 +761,14 @@ jobs:
         # Use the bash shell included with Git for Windows.
         shell: bash
         run: |
-          cd build/src/RelWithDebInfo && file *tests.exe bench*.exe libsecp256k1-*.dll || true
+          cd build/bin/RelWithDebInfo && file *tests.exe bench*.exe libsecp256k1-*.dll || true
 
       - name: Check
         run: |
           ctest -C RelWithDebInfo --test-dir build -j ([int]$env:NUMBER_OF_PROCESSORS + 1)
-          build\src\RelWithDebInfo\bench_ecmult.exe
-          build\src\RelWithDebInfo\bench_internal.exe
-          build\src\RelWithDebInfo\bench.exe
+          build\bin\RelWithDebInfo\bench_ecmult.exe
+          build\bin\RelWithDebInfo\bench_internal.exe
+          build\bin\RelWithDebInfo\bench.exe
 
   win64-native-headers:
     name: "x64 (MSVC): C++ (public headers)"
@@ -790,6 +800,7 @@ jobs:
       RECOVERY: 'yes'
       EXTRAKEYS: 'yes'
       SCHNORRSIG: 'yes'
+      MUSIG: 'yes'
       ELLSWIFT: 'yes'
 
     steps:

.gitignore

@@ -11,6 +11,7 @@ ecdh_example
 ecdsa_example
 schnorr_example
 ellswift_example
+musig_example
 *.exe
 *.so
 *.a

CHANGELOG.md

@@ -5,7 +5,26 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.6.0] - 2024-11-04
+
+#### Added
+ - New module `musig` implements the MuSig2 multisignature scheme according to the [BIP 327 specification](https://github.com/bitcoin/bips/blob/master/bip-0327.mediawiki). See:
+   - Header file `include/secp256k1_musig.h` which defines the new API.
+   - Document `doc/musig.md` for further notes on API usage.
+   - Usage example `examples/musig.c`.
+ - New CMake variable `SECP256K1_APPEND_LDFLAGS` for appending linker flags to the build command.
+
+#### Changed
+ - API functions now use a significantly more robust method to clear secrets from the stack before returning. However, secret clearing remains a best-effort security measure and cannot guarantee complete removal.
+ - Any type `secp256k1_foo` can now be forward-declared using `typedef struct secp256k1_foo secp256k1_foo;` (or also `struct secp256k1_foo;` in C++).
+ - Organized CMake build artifacts into dedicated directories (`bin/` for executables, `lib/` for libraries) to improve build output structure and Windows shared library compatibility.
+
+#### Removed
+ - Removed the `secp256k1_scratch_space` struct and its associated functions `secp256k1_scratch_space_create` and `secp256k1_scratch_space_destroy` because the scratch space was unused in the API.
+
+#### ABI Compatibility
+The symbols `secp256k1_scratch_space_create` and `secp256k1_scratch_space_destroy` were removed.
+Otherwise, the library maintains backward compatibility with versions 0.3.x through 0.5.x.
 
 ## [0.5.1] - 2024-08-01
 
@@ -143,7 +162,7 @@ This version was in fact never released.
 The number was given by the build system since the introduction of autotools in Jan 2014 (ea0fe5a5bf0c04f9cc955b2966b614f5f378c6f6).
 Therefore, this version number does not uniquely identify a set of source files.
 
-[unreleased]: https://github.com/bitcoin-core/secp256k1/compare/v0.5.1...HEAD
+[0.6.0]: https://github.com/bitcoin-core/secp256k1/compare/v0.5.1...v0.6.0
 [0.5.1]: https://github.com/bitcoin-core/secp256k1/compare/v0.5.0...v0.5.1
 [0.5.0]: https://github.com/bitcoin-core/secp256k1/compare/v0.4.1...v0.5.0
 [0.4.1]: https://github.com/bitcoin-core/secp256k1/compare/v0.4.0...v0.4.1

CMakeLists.txt

@@ -1,14 +1,19 @@
 cmake_minimum_required(VERSION 3.16)
 
+#=============================
+# Project / Package metadata
+#=============================
 project(libsecp256k1
   # The package (a.k.a. release) version is based on semantic versioning 2.0.0 of
   # the API. All changes in experimental modules are treated as
   # backwards-compatible and therefore at most increase the minor version.
-  VERSION 0.5.2
+  VERSION 0.6.0
   DESCRIPTION "Optimized C library for ECDSA signatures and secret/public key operations on curve secp256k1."
   HOMEPAGE_URL "https://github.com/bitcoin-core/secp256k1"
   LANGUAGES C
 )
+enable_testing()
+list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
 if(CMAKE_VERSION VERSION_LESS 3.21)
   # Emulates CMake 3.21+ behavior.
@@ -26,15 +31,19 @@ endif()
 # https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html
 # All changes in experimental modules are treated as if they don't affect the
 # interface and therefore only increase the revision.
-set(${PROJECT_NAME}_LIB_VERSION_CURRENT 4)
-set(${PROJECT_NAME}_LIB_VERSION_REVISION 2)
-set(${PROJECT_NAME}_LIB_VERSION_AGE 2)
+set(${PROJECT_NAME}_LIB_VERSION_CURRENT 5)
+set(${PROJECT_NAME}_LIB_VERSION_REVISION 0)
+set(${PROJECT_NAME}_LIB_VERSION_AGE 0)
 
+#=============================
+# Language setup
+#=============================
 set(CMAKE_C_STANDARD 90)
 set(CMAKE_C_EXTENSIONS OFF)
 
-list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
-
+#=============================
+# Configurable options
+#=============================
 option(BUILD_SHARED_LIBS "Build shared libraries." ON)
 option(SECP256K1_DISABLE_SHARED "Disable shared library. Overrides BUILD_SHARED_LIBS." OFF)
 if(SECP256K1_DISABLE_SHARED)
@@ -51,6 +60,7 @@ option(SECP256K1_ENABLE_MODULE_ECDH "Enable ECDH module." ON)
 option(SECP256K1_ENABLE_MODULE_RECOVERY "Enable ECDSA pubkey recovery module." OFF)
 option(SECP256K1_ENABLE_MODULE_EXTRAKEYS "Enable extrakeys module." ON)
 option(SECP256K1_ENABLE_MODULE_SCHNORRSIG "Enable schnorrsig module." ON)
+option(SECP256K1_ENABLE_MODULE_MUSIG "Enable musig module." ON)
 option(SECP256K1_ENABLE_MODULE_ELLSWIFT "Enable ElligatorSwift module." ON)
 
 # Processing must be done in a topological sorting of the dependency graph
@@ -59,6 +69,14 @@ if(SECP256K1_ENABLE_MODULE_ELLSWIFT)
   add_compile_definitions(ENABLE_MODULE_ELLSWIFT=1)
 endif()
 
+if(SECP256K1_ENABLE_MODULE_MUSIG)
+  if(DEFINED SECP256K1_ENABLE_MODULE_SCHNORRSIG AND NOT SECP256K1_ENABLE_MODULE_SCHNORRSIG)
+    message(FATAL_ERROR "Module dependency error: You have disabled the schnorrsig module explicitly, but it is required by the musig module.")
+  endif()
+  set(SECP256K1_ENABLE_MODULE_SCHNORRSIG ON)
+  add_compile_definitions(ENABLE_MODULE_MUSIG=1)
+endif()
+
 if(SECP256K1_ENABLE_MODULE_SCHNORRSIG)
   if(DEFINED SECP256K1_ENABLE_MODULE_EXTRAKEYS AND NOT SECP256K1_ENABLE_MODULE_EXTRAKEYS)
     message(FATAL_ERROR "Module dependency error: You have disabled the extrakeys module explicitly, but it is required by the schnorrsig module.")
@@ -262,13 +280,6 @@ if(SECP256K1_BUILD_CTIME_TESTS)
   unset(msan_enabled)
 endif()
 
-include(CTest)
-# We do not use CTest's BUILD_TESTING because a single toggle for all tests is too coarse for our needs.
-mark_as_advanced(BUILD_TESTING)
-if(SECP256K1_BUILD_BENCHMARK OR SECP256K1_BUILD_TESTS OR SECP256K1_BUILD_EXHAUSTIVE_TESTS OR SECP256K1_BUILD_CTIME_TESTS OR SECP256K1_BUILD_EXAMPLES)
-  enable_testing()
-endif()
-
 set(SECP256K1_APPEND_CFLAGS "" CACHE STRING "Compiler flags that are appended to the command line after all other flags added by the build system. This variable is intended for debugging and special builds.")
 if(SECP256K1_APPEND_CFLAGS)
   # Appending to this low-level rule variable is the only way to
@@ -284,6 +295,15 @@ if(SECP256K1_APPEND_LDFLAGS)
   string(APPEND CMAKE_C_LINK_EXECUTABLE " ${SECP256K1_APPEND_LDFLAGS}")
 endif()
 
+if(NOT CMAKE_RUNTIME_OUTPUT_DIRECTORY)
+  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
+endif()
+if(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
+  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
+endif()
+if(NOT CMAKE_ARCHIVE_OUTPUT_DIRECTORY)
+  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
+endif()
 add_subdirectory(src)
 if(SECP256K1_BUILD_EXAMPLES)
   add_subdirectory(examples)
@@ -305,6 +325,7 @@ message("  ECDH ................................ ${SECP256K1_ENABLE_MODULE_ECDH}
 message("  ECDSA pubkey recovery ............... ${SECP256K1_ENABLE_MODULE_RECOVERY}")
 message("  extrakeys ........................... ${SECP256K1_ENABLE_MODULE_EXTRAKEYS}")
 message("  schnorrsig .......................... ${SECP256K1_ENABLE_MODULE_SCHNORRSIG}")
+message("  musig ............................... ${SECP256K1_ENABLE_MODULE_MUSIG}")
 message("  ElligatorSwift ...................... ${SECP256K1_ENABLE_MODULE_ELLSWIFT}")
 message("Parameters:")
 message("  ecmult window size .................. ${SECP256K1_ECMULT_WINDOW_SIZE}")

Makefile.am

@@ -195,6 +195,17 @@ ellswift_example_LDFLAGS += -lbcrypt
 endif
 TESTS += ellswift_example
 endif
+if ENABLE_MODULE_MUSIG
+noinst_PROGRAMS += musig_example
+musig_example_SOURCES = examples/musig.c
+musig_example_CPPFLAGS = -I$(top_srcdir)/include -DSECP256K1_STATIC
+musig_example_LDADD = libsecp256k1.la
+musig_example_LDFLAGS = -static
+if BUILD_WINDOWS
+musig_example_LDFLAGS += -lbcrypt
+endif
+TESTS += musig_example
+endif
 endif
 
 ### Precomputed tables
@@ -254,6 +265,7 @@ maintainer-clean-local: clean-testvectors
 ### Additional files to distribute
 EXTRA_DIST = autogen.sh CHANGELOG.md SECURITY.md
 EXTRA_DIST += doc/release-process.md doc/safegcd_implementation.md
+EXTRA_DIST += doc/ellswift.md doc/musig.md
 EXTRA_DIST += examples/EXAMPLES_COPYING
 EXTRA_DIST += sage/gen_exhaustive_groups.sage
 EXTRA_DIST += sage/gen_split_lambda_constants.sage
@@ -281,6 +293,10 @@ if ENABLE_MODULE_SCHNORRSIG
 include src/modules/schnorrsig/Makefile.am.include
 endif
 
+if ENABLE_MODULE_MUSIG
+include src/modules/musig/Makefile.am.include
+endif
+
 if ENABLE_MODULE_ELLSWIFT
 include src/modules/ellswift/Makefile.am.include
 endif

README.md

@@ -21,6 +21,7 @@ Features:
 * Optional module for ECDH key exchange.
 * Optional module for Schnorr signatures according to [BIP-340](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki).
 * Optional module for ElligatorSwift key exchange according to [BIP-324](https://github.com/bitcoin/bips/blob/master/bip-0324.mediawiki).
+* Optional module for MuSig2 Schnorr multi-signatures according to [BIP-327](https://github.com/bitcoin/bips/blob/master/bip-0327.mediawiki).
 
 Implementation details
 ----------------------