#fully #homomorphic #encryption #fhe #cryptography


Cuda implementation for the concrete FHE library

1 unstable release

Uses new Rust 2021

0.1.0 Jul 6, 2022

#893 in Cryptography

24 downloads per month


533 lines



This repository holds the code for GPU acceleration of Zama's variant of TFHE. It implements CUDA/C++ functions to perform homomorphic operations on LWE ciphertexts.

In this first API, it provides functions to allocate memory on the GPU, to copy data back and forth between the CPU and the GPU, to create and destroy Cuda streams, etc.:

  • cuda_create_stream, cuda_destroy_stream
  • cuda_malloc, cuda_check_valid_malloc
  • cuda_memcpy_async_to_cpu, cuda_memcpy_async_to_gpu
  • cuda_get_number_of_gpus
  • cuda_synchronize_device The cryptographic operations it provides are:
  • an amortized implementation of the TFHE programmable bootstrap: cuda_bootstrap_amortized_lwe_ciphertext_vector_32 and cuda_bootstrap_amortized_lwe_ciphertext_vector_64
  • a low latency implementation of the TFHE programmable bootstrap: cuda_bootstrap_low latency_lwe_ciphertext_vector_32 and cuda_bootstrap_low_latency_lwe_ciphertext_vector_64
  • the keyswitch: cuda_keyswitch_lwe_ciphertext_vector_32 and cuda_keyswitch_lwe_ciphertext_vector_64

These C++/CUDA functions are available to the Concrete-core implementation via a dedicated Rust API, which is wrapped in the backend_cuda of concrete-core.


Disclaimer: Compilation on Windows/Mac is not supported yet. Only Nvidia GPUs are supported.

  • nvidia driver - for example, if you're running Ubuntu 20.04 check this page for installation
  • nvcc >= 10.0
  • gcc >= 8.0 - check this page for more details about nvcc/gcc compatible versions
  • cmake >= 3.8


The concrete-cuda functions are available in concrete-core via the backend_cuda. To compile concrete-core with the Cuda backend, install the aforementioned dependencies, then in concrete-core type:

cargo build --release --features=backend_cuda

Standalone Cuda files compilation

The Cuda project held in concrete-cuda can be compiled separately from the Rust project in the following way:

git clone git@github.com:zama-ai/concrete-core
cd concrete-core/concrete-cuda/cuda
mkdir build
cd build
cmake ..

The compute capability is detected automatically (with the first GPU information) and set accordingly.