一個python自定義的加密解密函數，下面的代碼實現了對字符串的加密盒解密，調用簡單

def encrypt(key, s):
    b = bytearray(str(s).encode("gbk"))
    n = len(b) # 求出 b 的字節數
    c = bytearray(n2)
    j = 0
    for i in range(0, n):
        b1 = b[i]
        b2 = b1 ^ key # b1 = b2^ key
        c1 = b2 % 16
        c2 = b2 // 16 # b2 = c216 + c1
        c1 = c1 + 65
        c2 = c2 + 65 # c1,c2都是0~15之間的數,加上65就變成了A-P 的字符的編碼
        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) # 計算 b 的字節數
    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 </pre>