Caesar's encryption and decryption and the realization of its Python code __python

1. Caesar Encryption

Caesar encrypts messages by shifting, with a maximum of 25 encryption methods (24 at the beginning, since the letters were 25)
For example, the plaintext ' I love ' shift 2-bit encrypted dark text is ' K nqxg ejkpc ' 2. Code implementation

def change (c,i):
    C = c.lower ()
    num = Ord (c)
    if Num >= and num <= 122:
        num = ((num-97) + i) % return
    chr (num)


def kaisa_jiami (string,i):
    string_new = "for
    s in string:
        string_new + = Chang E (s,i)
    print (string_new) return
    string_new

def kaisa_jiemi (string): To
    I in range (
        a): Print (' \ n ', I, ' \ n ')
        i + + 1
        kaisa_jiami (string,i)


def main ():
    print (' Select the action you want: ')
    print (' 1: Caesar encryption ')
    print (' 2: Caesar decryption ')
    choice = input ()
    if choice = = ' 1 ':
        string = input (' Enter the string to be encrypted: ')
        num = Int (input (' Please enter the number of digits to be offset: '))
        Kaisa_jiami (string,num)
    elif Choice = = ' 2 ':
        string = input (' Please enter the string you want to decrypt: ')
        Kaisa_jiemi (String)
    else:
        print (' input error, please try again. ')
        main ()

if __name__ = = ' __main__ ':
    Main ()

3. Effect

Encryption:

decryption:

Find the correct plaintext: