我正在将在Arduino Mega
上运行的应用程序移植到LPC824
。以下代码段对两个平台都有不同的工作原理。在lpc824中返回错误值的函数
/**
* Calculation of CMAC
*/
void cmac(const uint8_t* data, uint8_t dataLength) {
uint8_t trailer[1] = {0x80};
uint8_t bytes[_lenRnd];
uint8_t temp[_lenRnd];
memcpy(temp, data, dataLength);
concatArray(temp, dataLength, trailer, 1);
dataLength ++;
addPadding(temp, dataLength);
memcpy(bytes, _sk2, _lenRnd);
xorBytes(bytes,temp,_lenRnd);
aes128_ctx_t ctx;
aes128_init(_sessionkey, &ctx);
uint8_t* chain = aes128_enc_sendMode(bytes, _lenRnd, &ctx, _ivect);
Board_UARTPutSTR("chain\n\r");
printBytes(chain, 16, true);
memcpy(_ivect, chain, _lenRnd);
//memcpy(_ivect, aes128_enc_sendMode(bytes,_lenRnd,&ctx,_ivect), _lenRnd);
memcpy(_cmac,_ivect, _lenRnd);
Board_UARTPutSTR("Initialization vector\n\r");
printBytes(_ivect, 16, true);
}
我期待像{0x5d, 0xa8, 0x0f, 0x1f, 0x1c, 0x03, 0x7f, 0x16, 0x7e, 0xe5, 0xfd, 0xf3, 0x45, 0xb7, 0x73, 0xa2}
为chain
变量的值。但跟随功能的工作方式不同。函数内部的打印具有正确的值,我想要({5d, 0xa8, 0x0f, 0x1f, 0x1c, 0x03, 0x7f, 0x16, 0x7e, 0xe5, 0xfd, 0xf3, 0x45, 0xb7, 0x73, 0xa2})
。
但是,当函数返回chain
是具有不同的价值,比起我所期待的,我得到chain
{0x00, 0x20, 0x00, 0x10, 0x03, 0x01, 0x00, 0x00, 0xd5, 0x00, 0x00, 0x00, 0xd7, 0x00, 0x00, 0x00}
函数内使用下面的值,结果是正确的。但是它会给调用它的函数返回一个错误的值。为什么会这样呢?
uint8_t* aes128_enc_sendMode(unsigned char* data, unsigned short len, aes128_ctx_t* key,
const unsigned char* iv) {
unsigned char tmp[16];
uint8_t chain[16];
unsigned char c;
unsigned char i;
memcpy(chain, iv, 16);
while (len >= 16) {
memcpy(tmp, data, 16);
//xorBytes(tmp,chain,16);
for (i = 0; i < 16; i++) {
tmp[i] = tmp[i]^chain[i];
}
aes128_enc(tmp, key);
for (i = 0; i < 16; i++) {
//c = data[i];
data[i] = tmp[i];
chain[i] = tmp[i];
}
len -= 16;
data += 16;
}
Board_UARTPutSTR("Chain!!!:");
printBytes(chain, 16, true);
return chain;
}