用Python2710編寫凱撒密碼加密和解密程序？

s = raw_input('[開始加密]please input your str:')

s = list(s)

n = 0

for sw in s:

s[n] = chr(ord(sw)+3)

n = n + 1

sout = ''

for sw2 in s:

sout = sout + sw2

print '[加密結果]：',sout

解密的類似，主要用到ord、chr函數。