Awesome

NoMoreXOR.py

Tool to help guess a files 256 byte XOR key by using frequency analysis.

Usage

usage: NoMoreXOR.py [-h] [-a] [-c] [-xor key] [-g] [-o outfile] [-y YARARULES]
					Path

Tool to help guess a files 256 byte XOR key by using frequency analysis.

positional arguments:
Path                  Path to file to be analyzed

optional arguments:
-h, --help            show this help message and exit
-a, --analyze         Auto analyze the specified file by looking for all
					  possible XOR keys then apply each of them & scan with
				      YARA to try and determine if it's the correct XOR key
					 (requires an output file)
-c, --convert         Convert the input file to a hex_file (requires an
					  output file)
-xor key              XOR the file with the supplied XOR key (requires an
					  output file)
-g, --guess           Print out information from the hex_file including most
					  common characters and possible SHA256 keys
-o outfile, --out outfile
					  Name of output file to create
-y YARARULES, --yararules YARARULES
					  Path to YARA rules to be used during auto analysis if
					  different than what's hardcoded

Additional Reading

You can find more information in this blog post.