rot13加密解密

rot13加密解密小工具，python代码

def Upper(ch):
	if ch>='A' and ch<='Z':
		return True

def Lower(ch):
	if ch>='a' and ch<='z':
		return True

def rot13(s):
	flag = ''
	for i in s:
		if Upper(i) == True:
			if i>='A' and i<='M':
				flag += chr(ord(i)+13)
			else:
				flag += chr(ord(i)-13)
		elif Lower(i) == True:
			if i>='a' and i<='m':
				flag += chr(ord(i)+13)
			else:
				flag += chr(ord(i)-13)
		else:
			flag += i
	return flag

if __name__ == "__main__":
	s = 'synt{mur_VF_syn9_svtug1at}'
	print rot13(s)