[[alloc] init] C++ Cryptography Suite

Crypto3 is a modular, header-only C++ cryptography suite. It provides generic, STL-style interfaces for cryptographic primitives and the algebraic and mathematical structures used to build them.

Initially developed by =nil; Crypto3, the project is now maintained by [[alloc] init]. Guides are available under docs/manual.

Continuous integration currently covers Ubuntu x86-64 and macOS. Other operating systems and architectures are not continuously tested.

Repository Structure

Crypto3 is maintained as a monorepo. The source trees under libs are regular directories in this repository; cmake/modules is the only Git submodule.

root
|-- cmake
|   `-- modules              BoostCMake helper submodule
|-- docs                     Doxygen configuration and guides
`-- libs
    |-- algebra              Finite fields, curves, and pairings
    |-- benchmark_tools      Shared benchmark utilities
    |-- block                Block ciphers
    |-- codec                Encoding and decoding algorithms
    |-- containers           Merkle trees and related containers
    |-- hash                 Hash functions
    |-- kdf                  Key derivation functions, including PBKDF2
    |-- mac                  Message authentication codes
    |-- marshalling          Algebra, container, math, and numeric marshalling
    |-- math                 Polynomial arithmetic and FFT algorithms
    |-- modes                Cipher mode headers and tests
    |-- multiprecision       Extended multiprecision types and utilities
    |-- pkpad                Public-key padding schemes
    |-- pubkey               Public-key schemes and secret sharing
    |-- random               Randomization primitives
    |-- stream               Stream ciphers
    `-- zk                   Zero-knowledge proof systems

Requirements

• CMake 3.22 or newer
• A C++23-capable C++ compiler
• Boost with the container, random, filesystem, log, log_setup, program_options, thread, unit_test_framework, and timer components
• Git
• Doxygen and Graphviz when building the API documentation

The build does not enforce a specific Boost version. CI currently builds on Ubuntu 26.04 with its distribution compiler and on macOS 26 with Homebrew LLVM.

Clone And Build

The submodule URL uses GitHub SSH. If you do not have GitHub SSH credentials, configure this checkout to fetch GitHub dependencies over HTTPS:

git clone https://github.com/alloc-init/crypto3.git
cd crypto3
git config url."https://github.com/".insteadOf [email protected]:
git submodule update --init --recursive

cmake -S . -B build -DBUILD_TESTS=ON
cmake --build build --target tests --parallel
ctest --test-dir build --output-on-failure

Useful CMake options include:

• BUILD_TESTS: configure tests; defaults to ON
• BUILD_BENCH_TESTS: configure performance benchmarks; defaults to OFF
• BUILD_DOCS: configure Doxygen documentation support; defaults to OFF
• BUILD_EXAMPLES: build component examples; defaults to OFF
• BUILD_WITH_TARGET_ARCHITECTURE: override automatic target architecture detection

Generate the API documentation under build/docs with:

cmake -S . -B build -DBUILD_DOCS=ON
cmake --build build --target docs

On Apple Silicon, install the dependencies with brew install boost llvm and select Homebrew Clang when configuring:

cmake -S . -B build \
  -DBUILD_TESTS=ON \
  -DCMAKE_CXX_COMPILER=/opt/homebrew/opt/llvm/bin/clang++

Usage

Crypto3 components are header-only CMake INTERFACE libraries. In a CMake project that includes Crypto3, link only the components you use:

add_subdirectory(path/to/crypto3)
target_link_libraries(my_target PRIVATE crypto3::hash crypto3::algebra)

Component dependencies are expressed by their CMake targets. Buildable examples are located in component-specific libs/*/example directories. See the quickstart for an in-tree example.

Contributing

See the contribution guidelines.

Support

• Email: [email protected]
• Telegram: @alloc-init
• GitHub issues
• GitHub Discussions

License

The software is provided under the MIT License.