This is a formally verified implementation of Curve25519-based handshakes. The C code is automatically derived from the (verified) [original implementation](https://github.com/project-everest/hacl-star/tree/master/code/curve25519) in the [F* language](https://github.com/fstarlang/fstar) by [KreMLin](https://github.com/fstarlang/kremlin). In addition to the improved safety and security of the implementation, it is also significantly faster than the default implementation of Curve25519 in mbedTLS.
The caveat is that not all platforms are supported, although the version in `everest/library/legacy` should work on most systems. The main issue is that some platforms do not provide a 128-bit integer type and KreMLin therefore has to use additional (also verified) code to simulate them, resulting in less of a performance gain overall. Explictly supported platforms are currently `x86` and `x86_64` using gcc or clang, and Visual C (2010 and later).
