Concrete

The concrete ecosystem is a set of crates that implements Zama's variant of TFHE. In a nutshell, fully homomorphic encryption (FHE), allows you to perform computations over encrypted data, allowing you to implement Zero Trust services.

Concrete is based on the Learning With Errors (LWE) and the Ring Learning With Errors (RLWE) problems, which are well studied cryptographic hardness assumptions believed to be secure even against quantum computers.

Concrete crates

Concrete is implemented using the Rust Programming language, which allows very fast, yet very secure implementations.

The ecosystem is composed of several crates (packages in the Rust language):

concrete: A high-level library, useful to cryptographers that want to quickly implement homomorphic applications, without having to understand the details of the implementation.
concrete-core: A low-level library, useful to cryptographers who want the fastest implementation possible, with all the settings at their disposal.
concrete-boolean: A high-level library, implementing homomorphic Boolean gates, making it easy to run any kind of circuits over encrypted data.
concrete-npe: A noise propagation estimator, used in concrete to simulate the evolution of the noise in ciphertexts, through homomorphic operations.
concrete-csprng: A fast cryptographically secure pseudorandom number generator used in concrete-core.
concrete-commons: contains types and traits to manipulate objects in a consistent way throughout the ecosystem.

Installation

To use concrete, you will need the following things:

A Rust compiler
A C compiler & linker
make

The Rust compiler can be installed on Linux and macOS with the following command:

curl  --tlsv1.2 -sSf https://sh.rustup.rs | sh

Other rust installation methods are available on the rust website.

macOS

To have the required C compiler and linker you'll either need to install the full XCode IDE (that you can install from the AppleStore) or install the Xcode Command Line Tools by typing the following command:

xcode-select --install

Apple Silicon

Concrete currently only supports the x86_64 architecture. You can however, use it on Apple Silicon chip thanks to Rosetta at the expense of slower execution times.

To do so, you need to compile concrete for the x86_64 architecture and let Rosetta2 handle the conversion, we do that by using the x86_64 toolchain.

First install the needed rust toolchain:

# Install the macOS x86_64 toolchain (you only need to do this once)
rustup toolchain install --force-non-host stable-x86_64-apple-darwin

Then you can either:

Manually specify the toolchain to use in each of the cargo commands:

For example:

cargo +stable-x86_64-apple-darwin build
cargo +stable-x86_64-apple-darwin test

Or override the toolchain to use:

rustup override set stable-x86_64-apple-darwin
# cargo will use the `stable-x86_64-apple-darwin` toolchain.
cargo build

Linux

On linux, installing the required components depends on your distribution. But for the typical Debian-based/Ubuntu-based distributions, running the following command will install the needed packages:

sudo apt install build-essential

Windows

Concrete is not currently supported on Windows.

Contributing

There are two ways to contribute to Concrete:

you can open issues to report bugs or typos and to suggest new ideas
you can ask to become an official contributor by emailing hello@zama.ai. (becoming an approved contributor involves signing our Contributor License Agreement (CLA))

Only approved contributors can send pull requests, so please make sure to get in touch before you do!

Citing Concrete

To cite Concrete in academic papers, please use the following entry:

@inproceedings{WAHC:CJLOT20,
  title={CONCRETE: Concrete Operates oN Ciphertexts Rapidly by Extending TfhE},
  author={Chillotti, Ilaria and Joye, Marc and Ligier, Damien and Orfila, Jean-Baptiste and Tap, Samuel},
  booktitle={WAHC 2020--8th Workshop on Encrypted Computing \& Applied Homomorphic Cryptography},
  volume={15},
  year={2020}
}

Credits

This library uses several dependencies and we would like to thank the contributors of those libraries.

We thank Daniel May for supporting this project and donating the concrete crate.

License

This software is distributed under the BSD-3-Clause-Clear license. If you have any questions, please contact us at hello@zama.ai.

Disclaimers

Security Estimation

Security estimation, in this repository, used to be based on the LWE Estimator, with reduction_cost_model = BKZ.sieve. We are currently moving to the Lattice Estimator with red_cost_model = reduction.RC.BDGL16.

When a new update is published in the Lattice Estimator, we update parameters accordingly.

Side-Channel Attacks

Mitigation for side channel attacks have not yet been implemented in Concrete, and will be released in upcoming versions.

kino-ma/concrete-core