Encryption & Decryptio(Project-4).py

alphabet=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']

def encryption(plain_text,shift_key):
    cipher_text=""
    for char in plain_text:
        if char in alphabet:
            position=alphabet.index(char)
            new_position=(position+shift_key)%26  #try new syntax with both function combine
            cipher_text += alphabet[new_position]

        else:
            cipher_text += char
    print(f"Here's is the text after encryption->{cipher_text}")


def decryption(cipher_text,shift_key):
    plain_text=""
    for char in cipher_text:
        if char in alphabet:
            position=alphabet.index(char)
            new_position=(position-shift_key)%26  #here use to decrypt the msg
            plain_text += alphabet[new_position]

        else:
            plain_text += char
    print(f"Here's is the text after Decryption->{plain_text}")

wanna_end=False

while not wanna_end:
    what_to_do=input("Type 'encrypt' for Encryption, Type 'decrypt' for Decryption")
    text=input("Type Your Message:\n").lower()
    shift=int(input("Enter shift key\n"))
    if what_to_do == "encrypt":
        encryption(plain_text=text,shift_key=shift)
    elif what_to_do == "decrypt":
        decryption(cipher_text=text,shift_key=shift)
    play_again=input("Type 'Yes' to continue type 'No' to exit.\n")
    if play_again == "No":
        wanna_end=True
        print("Have a Nice Day!Bye.......")