Merge bitcoin-core/secp256k1#1266: release: Prepare for 0.3.1

898e1c6 release: Prepare for 0.3.1 (Tim Ruffing)
1d9a13f changelog: Remove inconsistent newlines (Tim Ruffing)
0e09166 changelog: Catch up in preparation of 0.3.1 (Tim Ruffing)

Pull request description:

ACKs for top commit:
  sipa:
    ACK 898e1c6
  jonasnick:
    ACK 898e1c6

Tree-SHA512: 941b1524f8b34ca803a2ede55a7baf54d2faa69a4c5e47254297e96cc4ac2121094ed90e7cd64a708f3e9af830b0de0ef3c755dfee1b01ce958cc998fc1a1311

CHANGELOG.md

@@ -5,7 +5,20 @@ 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]
+## [0.3.1] - 2023-04-10
+We strongly recommend updating to 0.3.1 if you use or plan to use Clang >=14 to compile libsecp256k1, e.g., Xcode >=14 on macOS has Clang >=14. When in doubt, check the Clang version using `clang -v`.
+
+#### Security
+ - Fix "constant-timeness" issue with Clang >=14 that could leave applications using libsecp256k1 vulnerable to a timing side-channel attack. The fix avoids secret-dependent control flow and secret-dependent memory accesses in conditional moves of memory objects when libsecp256k1 is compiled with Clang >=14.
+
+#### Added
+  - Added tests against [Project Wycheproof's](https://github.com/google/wycheproof/) set of ECDSA test vectors (Bitcoin "low-S" variant), a fixed set of test cases designed to trigger various edge cases.
+
+#### Changed
+ - Increased minimum required CMake version to 3.13. CMake builds remain experimental.
+
+#### ABI Compatibility
+The ABI is compatible with version 0.3.0.
 
 ## [0.3.0] - 2023-03-08
 
@@ -25,7 +38,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  - Removed the configuration header `src/libsecp256k1-config.h`. We recommend passing flags to `./configure` or `cmake` to set configuration options (see `./configure --help` or `cmake -LH`). If you cannot or do not want to use one of the supported build systems, pass configuration flags such as `-DSECP256K1_ENABLE_MODULE_SCHNORRSIG` manually to the compiler (see the file `configure.ac` for supported flags).
 
 #### ABI Compatibility
-
 Due to changes in the API regarding `secp256k1_context_static` described above, the ABI is *not* compatible with previous versions.
 
 ## [0.2.0] - 2022-12-12
@@ -45,7 +57,6 @@ Due to changes in the API regarding `secp256k1_context_static` described above,
  - Module `schnorrsig`: renamed `secp256k1_schnorrsig_sign` to `secp256k1_schnorrsig_sign32`.
 
 #### ABI Compatibility
-
 Since this is the first release, we do not compare application binary interfaces.
 However, there are earlier unreleased versions of libsecp256k1 that are *not* ABI compatible with this version.
 

configure.ac

@@ -6,7 +6,7 @@ AC_PREREQ([2.60])
 define(_PKG_VERSION_MAJOR, 0)
 define(_PKG_VERSION_MINOR, 3)
 define(_PKG_VERSION_PATCH, 1)
-define(_PKG_VERSION_IS_RELEASE, false)
+define(_PKG_VERSION_IS_RELEASE, true)
 
 # The library version is based on libtool versioning of the ABI. The set of
 # rules for updating the version can be found here: