异或加解密算法

const unsigned int key = 0x3feb3c98u;
void encode(const void* raw_in, void* raw_out, unsigned int len)
{
const unsigned char* in = (const unsigned char*)raw_in;
unsigned char* out = (unsigned char*)raw_out;
unsigned int seed = key;
for (size_t i = 0; i < len; ++i) {
unsigned char a = (in[i] ^ seed) >> 4;
unsigned char b = ((((unsigned int)in[i]) << 17) ^ seed) >> (17 - 4);
a &= 0x0F; //00001111
b &= 0xF0; //11110000=2⁷⁺²6+2⁵⁺²4=128+64+32+16=240
a = 0x0F & (a ^ (b << 3));
out[i] = a | b;
seed = (seed * 48475829 ^ seed ^ in[i]);
}
}
void decode(const void* raw_in, void* raw_out,unsigned int len)
{
const unsigned char* in = (const unsigned char*)raw_in;
unsigned char* out = (unsigned char*)raw_out;
unsigned int seed = key;
for (size_t i = 0; i < len; ++i) {
unsigned char a = in[i] & 15;
unsigned char b = in[i] & 240;
a = ((a << 4) ^ seed) & 240;
b = ((((unsigned int)b << 13) ^ seed) >> 17) & 15;
out[i] = a | b;
seed = (seed * 48475829 ^ seed ^ out[i]);
}
}

GO语言版本
func Enconding(raw_in []byte, raw_out []byte, len int) {
seed := key
for i := 0; i < len; i++ {
var a byte = byte((int(raw_in[i]) ^ seed) >> 4)
var b byte = byte(((int(raw_in[i]) << 17) ^ seed) >> (17 - 4))
a &= 0x0F
b &= 0xF0
raw_out[i] = (a | b)
seed ^= int(raw_in[i])
}
}
func Deconding(raw_in []byte, raw_out []byte, len int) {
seed := key
for i := 0; i < len; i++ {
var a byte = raw_in[i] & 0x0F
var b byte = raw_in[i] & 0xF0
a = byte((int((a << 4)) ^ seed) & 0xF0)
b = byte((((int(b) << (17 - 4)) ^ int(seed)) >> 17) & 0x0F)
raw_out[i] = a | b
seed ^= int(raw_in[i])
}
}