Toy Asymmetric Cryptography

This is a simple (and insecure) implementation of RSA and Diffie-Hellman. Most algorithms are proven (in French) in a LaTeX document.

Implementation

The Numbers.Make functor allows using any Concrete number representation:

• Int (31- or 63-bit OCaml integer, nice for testing purpose)
• Bigint (values are tagged, not directly saved as strings)

Phantom types allow statically differentiating public and private keys.

Structure

• numbers.ml, rsa.ml, and diffie_hellman.ml contain the library
• toy.ml is a simple CLI tool
• rsa.tex contains proofs in French

How to...

Install through opam

opam pin add toy-crypto https://github.com/ghuysmans/toy-crypto.git

Build from source (manually)

opam pin add -n .
opam install --deps-only toy-crypto
make

Compute Private Set Intersection

$ dune exec -- bin/main.exe psi-request -s s1 dh.params >q1
poire
pomme
fraise
banane
cerise
^D
$ dune exec -- bin/main.exe psi-request -s s2 dh.params >q2
poire
banane
clémentine
^D
$ dune exec -- bin/main.exe psi-reply -s s2 dh.params <q1 >r2
$ dune exec -- bin/main.exe psi-intersect -s s1 dh.params --other q2 --returned r2
poire
banane
$ dune exec -- bin/main.exe psi-reply -s s1 dh.params <q2 >r1
$ dune exec -- bin/main.exe psi-intersect -s s2 dh.params --other q1 --returned r1
poire
banane