prac/aes.hpp

/* Reference code from the Intel AES-NI whitepaper
 * http://www.intel.com/content/dam/doc/white-paper/advanced-encryption-standard-new-instructions-set-paper.pdf
 */

#include <wmmintrin.h>

inline __m128i AES_128_ASSIST (__m128i temp1, __m128i temp2)
{
    __m128i temp3;
    temp2 = _mm_shuffle_epi32 (temp2 ,0xff);
    temp3 = _mm_slli_si128 (temp1, 0x4);
    temp1 = _mm_xor_si128 (temp1, temp3);
    temp3 = _mm_slli_si128 (temp3, 0x4);
    temp1 = _mm_xor_si128 (temp1, temp3);
    temp3 = _mm_slli_si128 (temp3, 0x4);
    temp1 = _mm_xor_si128 (temp1, temp3);
    temp1 = _mm_xor_si128 (temp1, temp2);
    return temp1;
}

void AES_128_Key_Expansion (const unsigned char *userkey,
    unsigned char *key)
{
    __m128i temp1, temp2;
    __m128i *Key_Schedule = (__m128i*)key;
    temp1 = _mm_loadu_si128((__m128i*)userkey);
    Key_Schedule[0] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1 ,0x1);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[1] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x2);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[2] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x4);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[3] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x8);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[4] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x10);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[5] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x20);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[6] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x40);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[7] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x80);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[8] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x1b);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[9] = temp1;
    temp2 = _mm_aeskeygenassist_si128 (temp1,0x36);
    temp1 = AES_128_ASSIST(temp1, temp2);
    Key_Schedule[10] = temp1;
}

/* Note – the length of the output buffer is assumed to be a multiple of 16 bytes */
void AES_ECB_encrypt(const unsigned char *in, //pointer to the PLAINTEXT
    unsigned char *out, //pointer to the CIPHERTEXT buffer
    unsigned long length, //text length in bytes
    const char *key, //pointer to the expanded key schedule
    int number_of_rounds) //number of AES rounds 10,12 or 14
{
    __m128i tmp;
    int i,j;
    if(length%16)
        length = length/16+1;
    else
        length = length/16;
    for(i=0; i < length; i++){
        tmp = _mm_loadu_si128 (&((__m128i*)in)[i]);
        tmp = _mm_xor_si128 (tmp,((__m128i*)key)[0]);
        for(j=1; j <number_of_rounds; j++){
            tmp = _mm_aesenc_si128 (tmp,((__m128i*)key)[j]);
        }
        tmp = _mm_aesenclast_si128 (tmp,((__m128i*)key)[j]);
        _mm_storeu_si128 (&((__m128i*)out)[i],tmp);
    }
}