# Official Python wrapper for OpenFHE

## Table of Contents

- [Running from Docker](#running-from-docker)
- [Building from Source](#building-from-source)
  - [Prerequisites](#requirements)
  - [Linux Install](#linux)
    - [Installing directly on your system](#system-level-installation)
    - [Using Conda environments](#conda)
- [Running Examples](#code-examples)
- [OpenFHE Python Wrapper Documentation](#openfhe-python-wrapper-documentation)
- [Contributing Guide](#contributing-guide)

## Running from Docker

Please see [Instructions for the Docker setup](docker/README.md)

## Building from Source

### Requirements

Before building, make sure you have the following dependencies installed:

- [OpenFHE 1.1.3+](https://github.com/openfheorg/openfhe-development) by following the instructions in [OpenFHE Documentation](https://openfhe-development.readthedocs.io/en/latest/sphinx_rsts/intro/installation/installation.html)
- [Python 3.6+](https://www.python.org/)
- [pybind11](https://pybind11.readthedocs.io/en/stable/installing.html)

We recommend following OpenFHE C++ installation instructions first (which covers Linux, Windows and MacOS) and then getting back to this repo. See notes on installing `pybind11` below

### Linux

#### System-level installation

To install OpenFHE-python directly to your system, ensure the dependencies are set up. Then clone the repository, open a terminal in the repo folder and run the following commands:

```bash
pip install "pybind11[global]" 
mkdir build
cd build
cmake ..  # Alternatively, cmake .. -DOpenFHE_DIR=/path/to/installed/openfhe if you installed OpenFHE elsewhere
make
make install  # You may have to run sudo make install
```

At this point the `.so` file has been built. Your exact installation process will depend on your virtual environment.
Cmake will automatically find the python installation path, if unwanted, you can specify the python path by adding `-DPYTHON_EXECUTABLE_PATH=/path/to/python` to the cmake command.

If you see an error saying that one of OpenFHE .so files cannot be found when running a Python example (occurs only for some environments), 
add the path where the .so files reside to the `PYTHONPATH` environment variable:

```
export PYTHONPATH=(path_to_OpenFHE_so_files):$PYTHONPATH
```

In some environments (this happens rarely), it may also be necessary to add the OpenFHE libraries path to `LD_LIBRARY_PATH`.

#### Conda

Alternatively you can install the library and handle the linking via Conda. Clone the repository, open a terminal in the repo folder and run the following commands:

```bash
conda create -n ${ENV_NAME} python=3.{X} anaconda
```

where `${ENV_NAME}` should be replaced with the name of your environment, and `{X}` should be replaced with your desired python version. For example you might have `
conda create -n openfhe_python python=3.9 anaconda`. Now, you would install `pybind11` either via:

`pip install "pybind11[global]"` or via `conda install -c conda-forge pybind11`, but for now we recommend using the first method, with pip. Some users have reported issues when using the conda pybind11

Now, you would clone the repository, and run the following commands to install :

```bash
mkdir build
cd build
cmake .. # Add in -DOpenFHE_DIR=/path/to/installed/openfhe if you installed OpenFHE elsewhere
make
make install  # You may have to run sudo make install
```

Then, you can develop the library to link

```
cd ..
mkdir lib
mv *.so lib
conda develop lib
```

which creates a lib folder, moves the built `.so` file into that lib folder, and tells conda where to look for external libraries.

**Note** You may wish to copy the `.so` file to any projects of your own, or add it to your system path to source from.

## Code Examples

To get familiar with the OpenFHE Python API, check out the examples:

- FHE for arithmetic over integers (BFV):
  - [Simple Code Example](examples/pke/simple-integers.py)
  <!-- - [Simple Code Example with Serialization](examples/pke/simple-integers-serial.py) -->
- FHE for arithmetic over integers (BGV):
  - [Simple Code Example](examples/pke/simple-integers-bgvrns.py)
  <!-- - [Simple Code Example with Serialization](examples/pke/simple-integers-serial-bgvrns.py) -->
- FHE for arithmetic over real numbers (CKKS):
  - [Simple Code Example](examples/pke/simple-real-numbers.py)
  - [Advanced Code Example](examples/pke/advanced-real-numbers.py)
  - [Advanced Code Example for High-Precision CKKS](examples/pke/advanced-real-numbers-128.py)
  - [Arbitrary Smooth Function Evaluation](examples/pke/function-evaluation.py)
  - [Simple CKKS Bootstrapping Example](examples/pke/simple-ckks-bootstrapping.py)
  - [Advanced CKKS Bootstrapping Example](examples/pke/advanced-ckks-bootstrapping.cpp)
  - [Double-Precision (Iterative) Bootstrapping Example](examples/pke/iterative-ckks-bootstrapping.py)
- FHE for Boolean circuits and larger plaintext spaces (FHEW/TFHE):
  - [Simple Code Example with Symmetric Encryption](examples/binfhe/boolean.py)
  - [Truth Table Example](examples/binfhe/boolean-truth-table.py)
- Scheme Switching:
  - [Examples with Scheme Switching between CKKS and FHEW/TFHE](examples/pke/scheme-switching.py)
  <!-- - [Code with JSON serialization](examples/binfhe/boolean-serial-json.py) -->
  <!-- - [Code with Binary Serialization](examples/binfhe/boolean-serial-binary.py) -->
  <!-- - [Large-Precision Comparison](examples/binfhe/eval-sign.py) -->
  <!-- - [Small-Precison Arbitrary Function Evaluation](examples/binfhe/eval-function.py) -->
- Threshold FHE: 
  - [Code Example for BGV, BFV, and CKKS](examples/pke/threshold-fhe.py)
  - [Simple Interactive Bootstrapping Example](examples/pke/tckks-interactive-mp-bootstrapping.py)
  - [Interactive Bootstrapping after Chebyshev Approximation](examples/pke/tckks-interactive-mp-bootstrapping-Chebyschev.py)
  - [Code Example for BFV with 5 parties](examples/pke/threshold-fhe-5p.py)

## OpenFHE Python Wrapper Documentation

[OpenFHE Python Wrapper API Reference](https://openfheorg.github.io/openfhe-python/html/index.html)

## Contributing Guide

[OpenFHE Development - Contributing Guide](https://openfhe-development.readthedocs.io/en/latest/sphinx_rsts/contributing/contributing_workflow.html)