PR for Brute force parallel coordinated password guesser in Python

README.md

@@ -4,3 +4,12 @@ Files are:
 (1) Bank account statement
 (2) Few certificates
 where the first four letters are first four letters of your name along with your date and month of birthdate.
+
+- This code uses MPI to perform coordinated parallel guesses using multiple processors.
+- This is ideal for guessing long passwords with brute force using supercomputers.
+
+Use Python (tested with version `3.10`) to run this
+- [Optional] Create and use virtual environment: `python -m venv .venv && source .venv/bin/activate && pip install -r requirements.txt`
+- Run the code: `time mpiexec -n <num_procs> python guess_pdfPass-parallel.py`
+
+> Dependency: qpdf (https://github.com/qpdf/qpdf), tested with version 11.9.1. Make sure `qpdf` and its libraries are added to `PATH` and `LD_LIBRARY_PATH` respectively.

guess_pdfPass-parallel.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+"""
+Created on Sun Jun  16 21:57:11 2024
+@author: alankar
+Usage: time mpiexec -n <num_procs> python guess_pdfPass-parallel.py
+Dependency: qpdf (https://github.com/qpdf/qpdf), tested with version 11.9.1
+Note: Make sure qpdf and its libraries are added to PATH and LD_LIBRARY_PATH respectively
+Thanks: Samriddhi Sankar Maity
+- This code uses MPI to perform coordinated parallel guesses using multiple processors.
+- This is ideal for guessing long passwords with brute force using supercomputers
+"""
+
+import subprocess as sp
+from mpi4py import MPI
+from itertools import product
+
+## start parallel programming ---------------------------------------- #
+comm = MPI.COMM_WORLD
+rank = comm.Get_rank()
+size = comm.Get_size()
+
+verbose = False
+
+initial_known_pass = "9899"
+
+input_file = "sample.pdf"
+output_file = "sample-decrypt.pdf"
+
+# trying to guess unknown 6 digits
+tries = list(product(range(10),range(10),range(10),range(10),range(10),range(10)))
+
+for i in range(rank, len(tries), size):
+    guess_pass = "".join(str(x) for x in tries[i])
+    text = sp.getoutput(f'qpdf -password="{initial_known_pass}{guess_pass}" -decrypt {input_file} {output_file}')
+    if verbose:
+        print(f"{initial_known_pass}{guess_pass}: {text}", flush=True)
+    if "invalid password" not in text:
+        print(f"Password found: {initial_known_pass}{guess_pass}", flush=True)
+        comm.Abort()
+print("Set settings failed to guess the password.")

requirements.txt

@@ -0,0 +1 @@
+mpi4py==3.1.5 ; python_version >= "3.10" and python_version < "4.0"