Monocypher Documentation

You can build Monocypher as a library and link against it.

1. Run make to build the library.
2. Use the header src/monocypher.h and either lib/libmonocypher.a (static) or lib/libmonocypher.so (shared).

Default compiler settings are gcc -std=c99 with flags -pedantic -Wall -Wextra -O3 -march=native. To use a different compiler or flags, pass them to make:

$ make CC="clang -std=c11" CFLAGS="-O2"

To install Monocypher system-wide (defaults to /usr/local), run make followed by make install as root. You can customize the installation path using PREFIX or DESTDIR.

$ make install PREFIX="/opt"

After installation, use pkg-config to compile and link your programs:

$ gcc program.c $(pkg-config monocypher --cflags) -c
$ gcc program.o $(pkg-config monocypher --libs) -o program

If you want to perform a partial installation, use these sub-targets:

• install-lib: Installs only the library.
• install-doc: Installs only the documentation.
• install-pc: Installs only the pkg-config file.

The simplest way to integrate Monocypher into your project is to include the source files directly. This method supports C (C99 and later) and C++ (C++98 and later).

Include the following files:

• src/monocypher.h
• src/monocypher.c

If you require optional support for SHA-512 or Ed25519, you must also include:

• src/optional/monocypher-ed25519.h
• src/optional/monocypher-ed25519.c

/* Include these in your project build */
#include "src/monocypher.h"
#include "src/monocypher.c"

It is highly recommended to run the test suite at least once after installation to ensure correctness. A successful run will end with All tests OK!.

$ make test

For deeper verification, you can run the tests under Clang sanitizers or Valgrind using the provided scripts:

$ tests/test.sh
$ tests/coverage.sh

Monocypher provides several preprocessor flags for customization:

Performance Tuning

• -DBLAKE2_NO_UNROLLING: By default, the BLAKE2b inner loop is unrolled for speed (approx. 25% faster). On some embedded platforms, unrolling may be slower or consume too much code space. Enabling this flag reduces the binary size by ~5KB and may improve performance on constrained devices.

C++ Integration

• MONOCYPHER_CPP_NAMESPACE: When defined, Monocypher will be wrapped in a C++ namespace. If undefined (default), the library uses extern "C" automatically when the header is detected in C++ code.

Function Prefixing

To avoid name collisions with other libraries, you can rename all crypto_ functions to a custom prefix using the provided script:

./change-prefix.sh foobar

(This replaces crypto_ with foobar_)