[DISPARP] Distributed Systems and Parallel Programming - Coursework Project

University of Portsmouth, Year 3 Coursework

Many-time Pad Reuse brute-forcing

This repo has code for both a distributed and parallel (via worker_threads) for breaking ciphertexts enciphered using OTP and a repeated dictionary work as a key.

Requirements

Only Node and NPM are required to use this program. The dictionary is given (although you can replace this!)

• Node: >= 11
• NPM: >= 6.4.1
• Yarn (preferred over NPM): >= 1.12.3

Usage

0. Install all dependencies npm install
1. Build the TypeScript source code to JS: npm run build
2. Run the code:
   • For the distributed version, stand up the server with npm run start:cluster-naster 2. The number of clients required is the first argument - defaulting to 2.
   • Stand up clients with npm run start:cluster-client-client 192.168.0.12:5000. The only argument defines where the server is hosted.
   • For the parallel version, run npm run start:threaded 2. The only argument is the number of threads to spawn.
   • To run the worker farm code, prepend the aforementioned commands with farm-, npm run start:farm-cluster-worker etc.

Tech

Both versions run the same way. Clients are invoked with arguments:

• nodes in the pool
• node number
• ciphertext Nodes then get their words from a local dictionary and split this by their calculated block size, and their position (Block size = wordlist length / number of nodes). Nodes iterate through this, calculating (ciphertext ^ word). If the result is readable (defined by some regex: /^[a-zA-Z0-9\., \'\"\-_\:\(\)]+$/) then the key and decoded, readable, ciphertext is sent back to the host. If these two the CT and Key defined by the host, the program exits.

Distributed

A websocket server waits for the desired amount of clients. Upon reaching this number, a 'begin' event is sent to each client, as well as their number, size and ciphertext (defined by the interface in lib/shared.ts). Nodes do their brute-force loop and send back any candidates.

Threaded

Using worker_threads, threads are spawned according to the argument given to threaded.js. Worker threads are spawned with the new Worker(workerfile, workerData) constructor. Amount of threads, thread position and ciphertext is sent in workerData.

Results

Available on Google Sheets