凯撒密码加密（解密未写完）

import pyperclip

message = input('请输入您的信息：')#'This is my secret message.'
key = int(input('请输入您的KEY:'))#13

choice = int(input('请选择您的模块：1.加密；2.解密'))#'encrypt'\
mode1 = 'encrypt'
mode2 = 'decypt'

LETTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
translated = ''
message = message.upper()
if choice == 1:
for symbol in message:
if symbol in LETTERS:
num = LETTERS.find(symbol)
num = num + key
if num >= len(LETTERS):
num = num - len(LETTERS)
elif num < 0:
num = num + len(LETTERS)
translated = translated + LETTERS[num]

else:#将message中的非英文字符串直接保存到translated中
translated = translated + symbol
else:
print('wrong')

print(translated)
pyperclip.copy(translated)