Implemet_Caesar_Cipher.py

def encrypt_text(plaintext, n):
    ans = ""
    for i in range(len(plaintext)):
        ch = plaintext[i]
        if ch == " ":
            ans += " "
        elif (ch.isupper()):
            ans += chr((ord(ch) + n - 65) % 26 + 65)
        else:
            ans += chr((ord(ch) + n - 97) % 26 + 97)
    return ans


plaintext = "Prodigy Info TechE"
n = 3
print("Plain Text is : " + plaintext)
print("Shift pattern is : " + str(n))
print("Cipher Text is : " + encrypt_text(plaintext, n))

def decrypt():
    encrypted_message = input("Enter the message i.e to be decrypted: ").strip()
    letters = "abcdefghijklmnopqrstuvwxyz"
    k = int(input("Enter the key to decrypt: "))
    decrypted_message = ""
    for ch in encrypted_message:
        if ch in letters:
            position = letters.find(ch)
            new_pos = (position - k) % 26
            new_char = letters[new_pos]
            decrypted_message += new_char
        else:
            decrypted_message += ch
    print("Your decrypted message is:\n")
    print(decrypted_message)

decrypt()