RSA_Decrypt.py

import sympy

def rsa_decrypt(ciphertext, d, n):
    """
    Decrypts the RSA ciphertext using the private key (d, n).

    Parameters:
      - ciphertext (list): The ciphertext as a list of integers.
      - d (int): The private exponent.
      - n (int): The modulus.
    """
    # Decrypt each ciphertext block using m = c^d mod n
    plaintext = [pow(char, d, n) for char in ciphertext]
    return ''.join(chr(char) for char in plaintext)

# Given parameters of the problem
ciphertext = [153, 75, 309, 310, 74, 203, 208, 401, 310, 371, 363, 451, 125]
n = 485  # The modulus
e = 53   # The public exponent
p = 5    # The smaller prime factor of n
q = 97   # The larger prime factor of n

# Calculate φ(n) = (p - 1)(q - 1)
totient = (p - 1) * (q - 1)

# Calculate the private exponent d using the mod_inverse function
d = sympy.mod_inverse(e, totient)

print(rsa_decrypt(ciphertext, d, n))