// bitslice a value
void crypto1_bs_bitslice_value32(uint32_t value, bitslice_t bitsliced_value[], size_t bit_len){
// load nonce bytes with unswapped endianness
size_t bit_idx;
for(bit_idx = 0; bit_idx < bit_len; bit_idx++){
bool bit = get_bit(bit_len-1-bit_idx, rev32(value));
if(bit){
bitsliced_value[bit_idx].value = bs_ones.value;
} else {
bitsliced_value[bit_idx].value = bs_zeroes.value;
}
}
}
/***** BMP read *****/
int bmread(char *fn, int *x, int *y, unsigned char *buf3[3])
{
unsigned char bmHead[14];
unsigned char bmInfo[40];
unsigned char pbuf[1024];
int i,j,k;
int xx,yy,x0,y0;
FILE *fp;
unsigned char *b0;
int bits, ofbits;
if(NULL==(fp=fopen(fn,"rb")))
{
//printf("no file %s:",fn);
return(1);
}
fread(&bmHead,1,14,fp);
fread(&bmInfo,1,40,fp);
xx=rev32(&bmInfo[4]);
yy=rev32(&bmInfo[8]);
bits=rev16(&bmInfo[14]);
//fprintf(stderr, "wx = %d wy = %d\n",xx,yy);
if(!buf3[0])buf3[0]=malloc(xx*yy);
if(!buf3[1])buf3[1]=malloc(xx*yy);
if(!buf3[2])buf3[2]=malloc(xx*yy);
ofbits = rev32(&bmHead[10]);
if(bits==24){
fseek(fp, ofbits, SEEK_SET);
b0=malloc(xx*yy*3);
fread(b0,1,3*xx*yy,fp);
fclose(fp);
j=0;
for(y0=yy-1;y0>=0;y0--){
for(x0=0;x0<xx;x0++){
i=y0*xx+x0;
k=b0[j];j++; buf3[2][i]=k;
k=b0[j];j++; buf3[1][i]=k;
k=b0[j];j++; buf3[0][i]=k;
}}
free(b0);
*x=xx;*y=yy;
return(0);
}
if(bits==4){
b0=malloc(xx*yy/2);
k=ofbits -54;
k/=4;
fread(pbuf,1,k*4,fp);
fread(b0,1,xx*yy/2,fp);
fclose(fp);
j=0;
for(y0=yy-1;y0>=0;y0--){
for(x0=0;x0<xx;x0++){i=y0*xx+x0;
if(j&1) k=b0[j/2]&0x0f;
else k=b0[j/2]>>4;
j++;
buf3[0][i]=pbuf[ k*4+2 ];
buf3[1][i]=pbuf[ k*4+1 ];
buf3[2][i]=pbuf[ k*4+0 ];
}}
free(b0);
*x=xx;*y=yy;
return(0);
}
// note that PRN is not created with security in mind - just using a simple seed
BOOL hitag2_crypto_auth(BYTE *response, BYTE *hexkey)
{
BYTE tmp[65], tmphex[9];
unsigned long long key;
unsigned long uid;
unsigned long initvec;
// use default transport key if none specified
if(strlen(hexkey) == 0)
hexkey= HITAG2_KEY_DEFAULT;
// get UID for initialisation
if(!hitag2_get_uid(tmp))
return FALSE;
// convert to numerics for crypto routines
uid= hexreversetoulong(tmp);
key= hexreversetoulonglong(hexkey);
// generate 32 bit PRN for challenge
srand(Led_Count);
initvec= rand();
initvec <<= 16;
initvec += rand();
// prepare to send IV in the clear to tag
ulongtobinstring(tmp, initvec, 32);
// convert IV to MSB for crypto routines
binstringtohex(tmphex, tmp);
initvec= hexreversetoulong(tmphex);
// initialise crypto
hitag2_init(&Hitag_Crypto_State, rev64(key), rev32(uid), rev32(initvec));
// send inverse of 1st 32bits of keystream to tag for authentication
ulongtobinstring(tmp + 32, hitag2_crypt(0xFFFFFFFF, 32), 32);
// restart the tag & auth process
if(!hitag2_get_uid(TmpBuff))
return FALSE;
// wait for RX->TX period, then send PRN+secret
if(!rwd_send(tmp, strlen(tmp), NO_RESET, BLOCK, RWD_STATE_WAKING, RFIDlerConfig.FrameClock, 0, RFIDlerConfig.RWD_Wait_Switch_RX_TX, RFIDlerConfig.RWD_Zero_Period, RFIDlerConfig.RWD_One_Period, RFIDlerConfig.RWD_Gap_Period, RFIDlerConfig.RWD_Wait_Switch_TX_RX))
return FALSE;
// skip 1/2 bit to synchronise manchester
HW_Skip_Bits= 1;
// get 37 bit response: sync + config byte + 24 bit TAG pwd
if(read_ask_data(RFIDlerConfig.FrameClock, RFIDlerConfig.DataRate, tmp, 37, RFIDlerConfig.Sync, RFIDlerConfig.SyncBits, RFIDlerConfig.Timeout, ONESHOT_READ, BINARY) == 37)
{
// check sync bits
if (memcmp(tmp, Hitag2Sync, 5) != 0)
return FALSE;
CryptoActive= TRUE;
// decrypt
binarraytohex(response, tmp + 5, 32);
return hitag2_hex_crypt(response, response);
}
return FALSE;
}
void scp256_unpack(scp256 *r, const unsigned char x[32]){
unsigned char t[32];
rev32(t, x);
scp256_from32bytes(r, t);
}
void scp256_pack(unsigned char x[32], scp256 *r){
unsigned char t[32];
scp256_to32bytes(t, r);
rev32(x, t);
}
