#include "encrypt.h"

/* TEA加密算法的加密过程 */
void tea_encrypt(uint32_t *en, uint32_t *k) 
{
    uint32_t v[2];
    v[0] = *(uint32_t*)(0x1FFF7590);
    v[1] = *(uint32_t*)(0x1FFF7590 + 4);
    uint32_t v0 = v[0], v1 = v[1], sum = 0, i;           // 初始化v0, v1, sum
    uint32_t delta = 0x9e3779b9;                          // 初始化delta
    uint32_t k0 = k[0], k1 = k[1], k2 = k[2], k3 = k[3];   // 初始化密钥k
    for (i = 0; i < 32; i++) {                            // 执行32轮加密
        sum += delta;
        v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
        v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
    }
    en[0] = v0;                                            // 返回加密结果
    en[1] = v1;
   
//    term_printf("%x %x", v[0], v[1]);
}

/* TEA加密算法的解密过程 */
void tea_decrypt(uint32_t *v, uint32_t *k) 
{
	uint32_t delta = 0x9e3779b9;                          // 初始化delta
//    uint32_t v0 = 0x93ae5ba8, v1 = 0xc5ba4e82, sum = delta << 5, i;    // 初始化v0, v1, sum
    uint32_t v0 = g_stConfigInfo.encrypt_0, v1 = g_stConfigInfo.encrypt_1, sum = delta << 5, i;    // 初始化v0, v1, sum
    uint32_t k0 = k[0], k1 = k[1], k2 = k[2], k3 = k[3];   // 初始化密钥k
    for(i = 0; i < 32; i++) {                             // 执行32轮解密
        v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3);
        v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1);
        sum -= delta;
    }
    v[0] = v0;                                            // 返回解密结果
    v[1] = v1;
    
//    term_printf("%x %x", v[0], v[1]);
}

/*
 * 判断密文是否正确
 *
 */
uint8_t JudgeEncrypt()
{
    uint32_t encryptCode[2] = {0};
    uint32_t key[] = {0x509770ff, 0x29c6b369, 0x4da2c125, 0x7d729015}; //密钥可能要打散位置，不在这里定死
    tea_decrypt(encryptCode, key);
    return ((*(uint32_t*)(0x1FFF7590)) == encryptCode[0] && (*(uint32_t*)(0x1FFF7590 + 4)) == encryptCode[1]);
}