fex-crypto 1.0b1

FEX v1.0-beta: Fast Encryption eXchange (novel symmetric cipher)

FEX Crypto v1.0-beta: Fast Encryption eXchange

WARNING: This is a beta, experimental cryptographic algorithm. It is NOT cryptographically proven or reviewed. DO NOT use in production or for sensitive data!

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Overview

FEX (Fast Encryption eXchange) is a novel symmetric block cipher designed for high performance and flexibility. It features:

• 128-bit block size
• Variable key length: 16 to 1024 bits
• Custom S-box, P-box, and key schedule (not derived from any standard cipher)
• Optimized for speed using efficient bitwise operations
• Python bindings via pybind11 for easy integration

This is a research beta. Security is NOT guaranteed.

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Features

• Block-based encryption (128 bits per block)
• Variable key length (16–1024 bits)
• Custom substitution-permutation network (SPN) with unique S-box and P-box
• Simple, fast key schedule
• C++ and Python API

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C++ Usage Example

#include "fex.h"
#include <vector>
#include <iostream>

int main() {
    std::vector<uint8_t> key = {/* your key bytes */};
    std::vector<uint8_t> data = {/* your data bytes */};
    FEX fex(key.data(), key.size());
    // Pad data
    auto padded = FEX::pad(data);
    // Encrypt in-place
    for (size_t i = 0; i < padded.size(); i += FEX::BLOCK_SIZE)
        fex.encrypt_block(&padded[i]);
    // Decrypt in-place
    for (size_t i = 0; i < padded.size(); i += FEX::BLOCK_SIZE)
        fex.decrypt_block(&padded[i]);
    // Unpad
    auto recovered = FEX::unpad(padded);
    // ...
}

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Python Usage Example

import fex

# Use a 256-bit key for this example
my_key = b'This is my secret 32-byte key!!'
my_data = b'This is the data to be encrypted.'

encrypted = fex.encrypt(my_data, my_key)
decrypted = fex.decrypt(encrypted, my_key)

print("Original:", my_data)
print("Encrypted:", encrypted.hex())
print("Decrypted:", decrypted)

assert my_data == decrypted

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Building the Python Module

1. Install pybind11:

   pip install pybind11
   

2. Build the module:

   cd Fex
   python setup.py build_ext --inplace
   

3. Use import fex in Python.

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Security Warning

This is a beta, experimental cipher. It has NOT been reviewed or proven secure. Do NOT use for real-world or production cryptography. For research and educational use only!