Hello!

This is a "simple" Rust implementation of DES. I made this to have a hackable version of DES I could cryptanalyze.

Running

run cargo test to run test and cargo run --release to run the cryptanalysis (in src/bin/jupiter.rs). It's important to use --release as otherwise it will be build a debug build and be very slow.

xoxo

Potential improvments:

• perf seems to show that permute is a significant portion of the runtime, so maybe we should speed it up.
• https://stackoverflow.com/questions/43575633/fast-bit-permutation
• In general, the bit operation LUTs in this are design for 1-indexed left-to-right binary representations. Mordern software works with 0-indexed right-to-left. This makes everything awkward. It would be nice to transform the LUTs before compilation instead of transforming the indexes at runtime.
• make asserts debug_asserts.
• opt-level=3

Notes (perosnal!!)

Current best runtime 3.885 seconds remove asserts (and losing some of the type guarentees) makes it run at 2.765 seconds. about 1.1 seconds less. 28% decrease. Small potatoes

Made expansion fast. now it's 1.846 sec with no other optimization. 😎

Made the P permutation fast. now it's 0.602 seconds. I don't think opt-level=3 or debug_asserts are gonna do much.