https://github.com/amaitou/xorcry
Simple encryption tool designed to perform a bitwise XOR operation (XORing) on the contents of files with specific extensions in a given directory or file path. The XOR operation is executed using a user-defined key to encrypt the data.
https://github.com/amaitou/xorcry
crypter cryptography python3 ransomware xor xor-cipher
Last synced: 2 months ago
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Simple encryption tool designed to perform a bitwise XOR operation (XORing) on the contents of files with specific extensions in a given directory or file path. The XOR operation is executed using a user-defined key to encrypt the data.
- Host: GitHub
- URL: https://github.com/amaitou/xorcry
- Owner: amaitou
- License: mit
- Created: 2021-03-19T10:29:30.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2024-07-26T23:20:55.000Z (about 1 year ago)
- Last Synced: 2025-03-24T12:39:50.680Z (6 months ago)
- Topics: crypter, cryptography, python3, ransomware, xor, xor-cipher
- Language: Python
- Homepage:
- Size: 44.9 KB
- Stars: 20
- Watchers: 1
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
------------------
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# Xorcry
Xorcry is an open-source ransomware written in python3 to explain how actually a ransomware or a crypter with a given cryptography algorithm do works.
Before using this script, specify the path that you want to encrypt
```python
self.path = ""
```
# Why?
as a curious person, I really love to understand how things get to work deeply, and one of the questions that I've been asking for a long time was how does the ransomware work? after a lot of disappointing research to give my question a clear answer, I started diving into cryptography algorithms and malware understanding, so without any further ado let's leave this boring introduction aside a bit and go with the cool part.
## How Does Xorcry Work?
first of all, you must make sure that I did this tool only for educational purposes, secondly, if you are a cryptographer you will find this writeup boring you.
there are a lot of cryptography algorithms you can use to make ransomware but I'm not going to explain them for the reason that I didn't use any known crypto algorithm, in fact, what I did is reading files as binary and xor them with a given key and this is what called **xor cipher**, but wait, I said **xor cipher** hmmm what is this? well, this will be our next topic.
## Xor Cipher
I'll assume that you have a background about Logic gates and what are they, but if you don't I want you to take a deep look at this
article from Wikipedia :
https://en.wikipedia.org/wiki/Logic_gate
well as you noticed In **xor** operation, the output is true when the inputs differ. In other words, **xor** operation means either one but not both or none.
Below you can find the principles of **xor** (^ denotes the **xor** operation):
```
0 ^ 0 = 0
0 ^ 1 = 1
1 ^ 0 = 1
1 ^ 1 = 0
```
**xor** cipher employs the **xor** logical operation in order to encrypt data. First, a random key is generated or is chosen by you. Then, **xor** operation is performed using the key so that an encrypted data is created. In order to decrypt, the same key should be used and **xor** operation should be run again.
**xor** operation uses the same key for both encryption and decryption operations. That is why it is known as a symmetric encryption.
## Code Explaining
before covering the code explaining, I'll assume again that you have the basics of the programming language Python in order to understand The rest of the code because I will cover only the most important function which is :
```python
def encrypt(self , f) :
''' If the file's extension is one of the list declared above then start XoRing '''
if self.check_ex(f) :
try :
with open(f , mode = "rb") as _file :
rd = bytearray(_file.read())
for n , v in enumerate(rd) :
rd[n] = v ^ self.key
with open(f , mode = "wb") as _nf :
_nf.write(rd)
''' This exception is especially for file permissions '''
except :
pass
```
the first line I will talk about is the operation of reading the file we want to encrypt in binary mode and declare a variable where we will put the binary data as a list using the built-in function _bytearray()_, I found this article useful for those who want to understand how does the *bytearray()* work :
https://www.geeksforgeeks.org/python-bytearray-function/
after that, there is a for loop to edit the list by performing **xor** operation for each element in the list with the given key and finally rewrite the file we have opened previously with the new encrypted data.
## Contact Me
For Any Questions You Can Find Me on This Platforms :
* [Twitter][_1]
[_1]: https://twitter.com/amait0u
# Disclaimer
This program must be used for legal purposes! I am not responsible for anything you do with it.