Building a Curve25519 Hardware Accelerator re Betrusted.io FPGA Enclave, Precursor DevKit

[grarpamp]

https://www.bunniestudios.com/blog/?p=6140
https://twitter.com/bunniestudios

https://github.com/betrusted-io
https://ci.betrusted.io/betrusted-soc/doc/engine.html
https://www.crowdsupply.com/sutajio-kosagi/precursor
https://www.youtube.com/watch?v=Hzb37RyagCQ
https://www.youtube.com/watch?v=_pIr3Q7gqNI
https://www.youtube.com/watch?v=w8BA6_9HCzk
https://www.bunniestudios.com/blog/?cat=71
https://xobs.io/precursor-and-renode/

https://github.com/dalek-cryptography
https://signal.org/docs/specifications/doubleratchet/
https://cr.yp.to/ecdh/curve25519-20060209.pdf
https://doi.org/10.1145/3312742
https://research.nccgroup.com/2020/09/28/faster-modular-inversion-and-legendre-symbol-and-an-x25519-speed-record/
https://github.com/jonas-schievink/rustasm6502
https://en.wikipedia.org/wiki/Rubber-hose_cryptanalysis

The double-ratchet algorithm is a soup of cryptographic components,
but one of the most computationally expensive portions is the
“Diffie-Hellman (DH) key exchange”, using Elliptic Curve
Diffie-Hellman (ECDH) with Curve25519. ... There are a few strategies
to rectify this... I hope that by sharing my experience, someone else
will find Curve25519 a little more approachable, too!

Betrusted is a secure and private communications system. It gives
users an evidence-based reason to believe that private matters are
kept private.
Betrusted is more than just an app, and more than just a gadget – it
is a co-designed hardware + software solution that provides safe
defaults for everyday users. It’s also open source, empowering
advanced users to analyze, extend and explore this secure mobile
computer.