This example demonstrates basic polymorphic obfuscation techniques, including encryption, variable code structure, and behavioral adaptation.

Polymorphic obfuscation algorithm involves several complex techniques to ensure the code changes its form each time it is executed, while maintaining its original functionality. Here’s a detailed overview and an example of how you might implement such an algorithm.

Key Techniques in Polymorphic Obfuscation

Code Obfuscation:
- Use encryption, compression, or other obfuscation methods to conceal the code's true nature.
- Example: Encrypt the main body of the code and add a decryption function that decrypts the code before execution[3].
Dynamic Encryption Keys:
- Use different encryption keys for each new instance of the code.
- Example: Generate a random key each time the code is executed and use it to decrypt the payload[1].
Variable Code Structure:
- Change the code structure by rearranging subroutines or using different registers.
- Example: Rearrange the order of functions or use register swapping to alter the code's appearance[1].
Behavioral Adaptation:
- Alter the execution patterns to blend in with normal system processes.
- Example: Use different execution paths or timing to make the code harder to detect[1].

Example Implementation

Here is a simplified example of a polymorphic obfuscation algorithm in Python, demonstrating some of these techniques:

Encryption and Decryption

import base64
import random
import string

def generate_random_key(length=16):
    return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(length))

def encrypt_code(code, key):
    # Simple XOR encryption for demonstration
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(code, key * (len(code) // len(key) + 1)))

def decrypt_code(encrypted_code, key):
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))

# Example code to be obfuscated
code = """
def main():
    print("Hello, World!")
    # Other code here...
if __name__ == "__main__":
    main()
"""

# Generate a random key
key = generate_random_key()

# Encrypt the code
encrypted_code = encrypt_code(code, key)

# Create the obfuscated code with a decryption function
obfuscated_code = f"""
import base64

def decrypt_code(encrypted_code, key):
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))

key = "{key}"
encrypted_code = "{encrypted_code}"

decrypted_code = decrypt_code(encrypted_code, key)
exec(decrypted_code)
"""

# Save the obfuscated code to a file
with open("obfuscated_code.py", "w") as f:
    f.write(obfuscated_code)

Variable Code Structure

To change the code structure, you can rearrange functions or use different registers. Here’s an example of rearranging functions:

# Original code
code = """
def function_a():
    print("Function A")

def function_b():
    print("Function B")

def main():
    function_a()
    function_b()

if __name__ == "__main__":
    main()
"""

# Rearrange the functions
functions = ["function_a", "function_b"]
random.shuffle(functions)

obfuscated_code = f"""
def {functions}():
    print("Function A")

def {functions[1]}():
    print("Function B")

def main():
    {functions}()
    {functions[1]}()

if __name__ == "__main__":
    main()
"""

Behavioral Adaptation

To adapt the behavior, you can introduce random delays or different execution paths:

import random
import time

# Original code
code = """
def main():
    print("Hello, World!")
    # Other code here...
if __name__ == "__main__":
    main()
"""

# Introduce random delays and different execution paths
obfuscated_code = f"""
import random
import time

def main():
    if random.random() < 0.5:
        time.sleep(random.uniform(0.1, 1.0))
    print("Hello, World!")
    # Other code here...
if __name__ == "__main__":
    main()
"""

Full Example

Here is a more comprehensive example that combines these techniques:

import base64
import random
import string
import time

def generate_random_key(length=16):
    return ''.join(random.choice(string.ascii_letters + string.digits) for _ in range(length))

def encrypt_code(code, key):
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(code, key * (len(code) // len(key) + 1)))

def decrypt_code(encrypted_code, key):
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))

# Example code to be obfuscated
code = """
def function_a():
    print("Function A")

def function_b():
    print("Function B")

def main():
    function_a()
    function_b()

if __name__ == "__main__":
    main()
"""

# Generate a random key
key = generate_random_key()

# Encrypt the code
encrypted_code = encrypt_code(code, key)

# Rearrange the functions
functions = ["function_a", "function_b"]
random.shuffle(functions)

# Create the obfuscated code with a decryption function and behavioral adaptation
obfuscated_code = f"""
import base64
import random
import time

def decrypt_code(encrypted_code, key):
    return ''.join(chr(ord(c) ^ ord(k)) for c, k in zip(encrypted_code, key * (len(encrypted_code) // len(key) + 1)))

key = "{key}"
encrypted_code = "{encrypted_code}"

decrypted_code = decrypt_code(encrypted_code, key)

def {functions}():
    print("Function A")
    if random.random() < 0.5:
        time.sleep(random.uniform(0.1, 1.0))

def {functions[1]}():
    print("Function B")
    if random.random() < 0.5:
        time.sleep(random.uniform(0.1, 1.0))

def main():
    {functions}()
    {functions[1]}()

if __name__ == "__main__":
    main()
"""

# Save the obfuscated code to a file
with open("obfuscated_code.py", "w") as f:
    f.write(obfuscated_code)

This example demonstrates basic polymorphic obfuscation techniques, including encryption, variable code structure, and behavioral adaptation. However, for real-world applications, more sophisticated methods and continuous evolution of the obfuscation techniques are necessary to evade detection by advanced security systems.