TFHE

TFHE is an FHE library written in C++ developed by Inpher It supports a variety of different libraries for underlying FFT operations.

TFHE was proposed in 2016 by Chillotti et al. and can be considered the successor of the FHEW library. TFHE is based on the CGGI scheme, more commonly known also as TFHE, and offers gate-by-gate bootstrapping with significantly reduced bootstrapping times, resulting in times of less than 0.1s compared to 6min for bootstrapping in the HElib library.

TFHE implements a variety of logic gates like OR, NOR, MUX that are generally implemented more efficiently than naive constructions from XOR and AND would be. However, the library provides no assistance with building more complex logic circuits like efficient comparators and adders. TFHE's source code is available under the Apache License~v2.0 and includes examples and documentation.

Usability

TFHE requires a lot of manual management of pointers. It uses raw pointers both for single Ciphertexts and to pass arrays of multiple Ciphertexts corresponding to the binary representation of a number. This circumvents a lot of the type safety possible in C++ and leads to frequent illegal memory access bugs during development.