import random
from sympy import isprime
import time
import matplotlib.pyplot as plt

def generate_keys(bit_length=32):
    while True:
        q = random.getrandbits(bit_length)
        if isprime(q):
            break
    g = random.randint(2, q - 1)
    x = random.randint(1, q - 2)
    h = pow(g, x, q)
    public_key = (q, g, h)
    private_key = (q, x)
    return public_key, private_key

def encrypt(public_key, message):
    q, g, h = public_key
    # Determine the maximum block size based on the size of q
    max_block_size = (q.bit_length() - 1) // 8
    encrypted_blocks = []
    for i in range(0, len(message), max_block_size):
        block = message[i:i+max_block_size]
        y = random.randint(1, q - 2)
        c1 = pow(g, y, q)
        m = int.from_bytes(block.encode(), 'big')
        s = pow(h, y, q)
        c2 = (m * s) % q
        encrypted_blocks.append((c1, c2))
    return encrypted_blocks

def decrypt(private_key, ciphertext):
    q, x = private_key
    decrypted_blocks = []
    for c1, c2 in ciphertext:
        s = pow(c1, x, q)
        m = (c2 * pow(s, q - 2, q)) % q
        block = m.to_bytes((m.bit_length() + 7) // 8, 'big').decode(errors='ignore')
        decrypted_blocks.append(block)
    return ''.join(decrypted_blocks)

# Example Usage
public_key, private_key = generate_keys()
print("Public Key:", public_key)
print("Private Key:", private_key)

encrypted_message = encrypt(public_key, "Hello, World!")
print("Encrypted Message:", encrypted_message)

decrypted_message = decrypt(private_key, encrypted_message)
print("Decrypted Message:", decrypted_message)

def main():
    public_key, private_key = generate_keys()
    print("Public Key:", public_key)
    print("Private Key:", private_key)
    encrypted_message = encrypt(public_key, "Hello, World!")
    print("Encrypted Message:", encrypted_message)
    decrypted_message = decrypt(private_key, encrypted_message)
    print("Decrypted Message:", decrypted_message)
    return encrypted_message, decrypted_message

# Measure execution times
execution_times = []
for _ in range(10):
    start_time = time.time()
    main()
    end_time = time.time()
    execution_times.append(end_time - start_time)
    
print(execution_times)

# Plot the execution times
plt.plot(execution_times, marker='o')
plt.xlabel('Run Number')
plt.ylabel('Execution Time (seconds)')
plt.title('Execution Times for Encrypting and Decrypting')
plt.show()