XCRYPT

An Xor CRYPToanalyser written in rust. This is a small project, mainly intended to be used in simple CTF challenges. This tool exploits some properties of XOR It has 3 modes of operation (currently).

Version 0.1.0 Checklist

• Update Cargo.toml to have correct info, and make sure it is displayed in clap
• Although crib and search is implemented in clap and in rust, need to join them
• Actually make github repo
• Make proper README.md
• Move key guessing functions outside lib.rs

Version 0.2.0 Checklist

• Better READEME.md
• Loading bar for really long files
• Add possibility for multiple different keys to be found
• Examples README
• Output multiple files if more than one key is chosen

Version 0.3.0 Checklist

• Better logging
• Implement key elimination and remove crib and search (which is less effective O(n^2) vs. O(n))
• Change loading bar style
• Check for repitions in key once it is solved, and reduce size if possible. i.e. "0x202020" => "0x20"
• Better CLI (maybe have different methods of running as subcommands). For example xcrypt common <FILE> and xcrypt crib offset <CRIB> <OFFSET> <FILE> and xcrypt crib search <CRIB> <SEARCH> <FILE>. May have different method in future the previous commands are just examples.

Version 0.4.0

• Maximum key size should be chosen algorithmically (i.e. for small input sizes (10-20 chars) max key input should be between 0 and 10) or maybe just a table for small values.
• Allow for iteration over values that aren't just bytes. For example each utf-8 character can be represented as a number. This would require anlysis of files before hand because if we were to handle utf-8 characters we would need to check that the whole file is utf-8.

Future Versions (To be announced)

• Move error messages to an other module
• Move test files to test folder (and make proper tests)
• Improve most common byte evaluator
• Add likelihood of the key found being correct (analyse difference between two known frequencies)
• Examine multiple key length guesses
• Make every method function through iterators to allow for large file size
• If we have multiple keys find the one that outputs most plaintext
• Add multiprocessing capabilities

Version 1.0.0 Checklist ??