Experiment 1

Monoalphabetic Cipher

Perform Monoalphabetic Cipher encryption and decryption using Python.

# MONO ALPHABETIC CIPHER
import random
def generate_key():
    letters = list("abcdefghijklmnopqrstuvwxyz")
    shuffled_letters = letters.copy() + ['1','2','3','4','5','6','7','8','9','0']
    random.shuffle(shuffled_letters)
    key = dict(zip(letters, shuffled_letters))
    return key
def encrypt(text, key):
    e_text = ""
    for char in text:
        if char in key:
            e_text += key[char]
        else:
            e_text += char
    return e_text

def decrypt(text, key):
    d_text = ""
    for char in text:
        if char in key.values():
            for k, v in key.items():
                if v == char:
                    d_text += k
                    break
        else:
            d_text += char
    return d_text

def main():
    text = input("Enter the text: ")
    ftext = text.lower()
    key = generate_key()
    print("Key: ", key)
    e_text = encrypt(ftext, key)
    print("Encrypted: ", e_text)
    d_text = decrypt(e_text, key)
    print("Decrypted : ", d_text)
main()