一个python自定义的加密解密函数，下面的代码实现了对字符串的加密盒解密，调用简单

def encrypt(key, s):      b = bytearray(str(s).encode("gbk"))      n = len(b) # 求出 b 的字节数      c = bytearray(n*2)      j = 0      for i in range(0, n):          b1 = b[i]          b2 = b1 ^ key # b1 = b2^ key          c1 = b2 % 16          c2 = b2 // 16 # b2 = c2*16 + c1          c1 = c1 + 65          c2 = c2 + 65 # c1,c2都是0~15之间的数,加上65就变成了A-P 的字符的编码          c[j] = c1          c[j+1] = c2          j = j+2      return c.decode("gbk")      def decrypt(key, s):      c = bytearray(str(s).encode("gbk"))      n = len(c) # 计算 b 的字节数      if n % 2 != 0 :          return ""      n = n // 2      b = bytearray(n)      j = 0      for i in range(0, n):          c1 = c[j]          c2 = c[j+1]          j = j+2          c1 = c1 - 65          c2 = c2 - 65          b2 = c2*16 + c1          b1 = b2^ key          b[i]= b1      try:          return b.decode("gbk")      except:          return "failed"      key = 15  s1 = encrypt(key, 'hello world')  s2 = decrypt(key, s1)  print s1,'\n',s2       # HGKGDGDGAGPCIHAGNHDGLG  # hello world