Safe_computing_ipynb_2_

import random

def caesar_cipher(text, shift, mode):
    result = ""
    for char in text:
        if char.isalpha():  # Encrypts only letters
            shift_amount = shift if mode == "encrypt" else -shift
            new_char = chr(((ord(char.lower()) - 97 + shift_amount) % 26) + 97)
            result += new_char.upper() if char.isupper() else new_char
        else:
            result += char  # Keeps spaces and punctuation unchanged
    return result

# Get user input
mode = input("Do you want to encrypt or decrypt? ").strip().lower()

if mode not in ["encrypt", "decrypt"]:
    print("Invalid mode! Please enter 'encrypt' or 'decrypt'.")
    exit()

message = input("Enter your message: ")
shift_input = input("Enter shift value (or type 'random'): ").strip().lower()

# Generate a random shift if "random" is entered
if shift_input == "random":
    shift = random.randint(1, 25)
else:
    try:
        shift = int(shift_input)
        if not (1 <= shift <= 25):  
            raise ValueError  # Ensures shift is within valid range
    except ValueError:
        print("Invalid shift value! Enter a number between 1 and 25 or type 'random'.")
        exit()

print(f"Using shift value: {shift}")  # Display the shift used
output = caesar_cipher(message, shift, mode)
print(f"Result: {output}")

Using shift value: 1
Result: ojhhfs