IP地址加密,请各位大神帮忙
这是一个有关IP地址加密的函数,麻烦各位大神帮我看看它用的方法和原理是什么,谢谢!
const unsigned char sbox[256] = {
0x91, 0x58, 0xb3, 0x31, 0x6c, 0x33, 0xda, 0x88,
0x57, 0xdd, 0x8c, 0xf2, 0x29, 0x5a, 0x08, 0x9f,
……
0xf4, 0xc6, 0xbc, 0xa2, 0x51, 0x58, 0xe8, 0xae,
};
……
F(uint64_t r, uint64_t R, uint64_t seed)
{
uint64_t r0, r1, r2, r3;
#define GETBYTE(R,n) ((((R)>>(n*8))^seed^r)&0xFF)
R ^= seed;
r0 = sbox[GETBYTE(R,0)]<< 0 | sbox[GETBYTE(R,1)]<< 8;
r1 = (sbox[GETBYTE(R,2)]<<16UL | sbox[GETBYTE(R,3)]<<24UL)&0x0ffffFFFFUL;
r2 = sbox[GETBYTE(R,4)]<< 0 | sbox[GETBYTE(R,5)]<< 8;
r3 = (sbox[GETBYTE(R,6)]<<16UL | sbox[GETBYTE(R,7)]<<24UL)&0x0ffffFFFFUL;
R = r0 ^ r1 ^ r2<<23UL ^ r3<<33UL;
return R;
}