BTEA算法C语言实现

来源：互联网发布：韩日军力对比知乎编辑：程序博客网时间：2024/04/25 15:18
#include <iostream>#include <stdio.h>using namespace std;#include <stdint.h>#define DELTA 0x9e3779b9#define MX (((z>>5^y<<2) + (y>>3^z<<4)) ^ ((sum^y) + (key[(p&3)^e] ^ z)))  void btea(uint32_t *v, int n, uint32_t const key[4]) {    uint32_t y, z, sum;    unsigned p, rounds, e;    if (n > 1) {          /* Coding Part */      rounds = 6 + 52/n;      sum = 0;      z = v[n-1];      do {        sum += DELTA;        e = (sum >> 2) & 3;        for (p=0; p<n-1; p++) {          y = v[p+1];          z = v[p] += MX;        }        y = v[0];        z = v[n-1] += MX;      } while (--rounds);    } else if (n < -1) {  /* Decoding Part */      n = -n;      rounds = 6 + 52/n;      sum = rounds*DELTA;      y = v[0];      do {        e = (sum >> 2) & 3;        for (p=n-1; p>0; p--) {          z = v[p-1];          y = v[p] -= MX;        }        z = v[n-1];        y = v[0] -= MX;      } while ((sum -= DELTA) != 0);    }  }int main(){    uint32_t const key[4]={0x01234567,0x89ABCDEF,0xFEDCBA98,0x76543210};    uint32_t data[2]={0x12345678,0x87654321};    uint32_t *sent=data;    btea(sent,2,key);    printf("coded:%x  %x\n",sent[0],sent[1]);    btea(sent,-2,key);    printf("decoded:%x  %x\n",sent[0],sent[1]);    return 0;}
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