/*
* Guess which key bytes could be strong and start actual computation of the key
*/
int PTW_computeKey(PTW_attackstate * state, uint8_t * keybuf, int keylen, int testlimit) {
int strongbytes[KEYHSBYTES];
double normal[KEYHSBYTES];
double ausreisser[KEYHSBYTES];
doublesorthelper helper[KEYHSBYTES];
int simple, onestrong, twostrong;
int i,j;
onestrong = (testlimit/10)*2;
twostrong = (testlimit/10)*1;
simple = testlimit - onestrong - twostrong;
PTW_tableentry (*table)[n] = alloca(sizeof(PTW_tableentry) * n * keylen);
if (table == NULL) {
printf("could not allocate memory\n");
exit(-1);
}
memcpy(table, state->table, sizeof(PTW_tableentry) * n * keylen);
// now, sort the table
for (i = 0; i < keylen; i++) {
qsort(&table[i][0], n, sizeof(PTW_tableentry), &compare);
strongbytes[i] = 0;
}
sorthelper (* sh)[n-1] = alloca(sizeof(sorthelper) * (n-1) * keylen);
if (sh == NULL) {
printf("could not allocate memory\n");
exit(-1);
}
for (i = 0; i < keylen; i++) {
for (j = 1; j < n; j++) {
sh[i][j-1].distance = table[i][0].votes - table[i][j].votes;
sh[i][j-1].value = table[i][j].b;
sh[i][j-1].keybyte = i;
}
}
qsort(sh, (n-1)*keylen, sizeof(sorthelper), &comparesorthelper);
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, simple)) {
return 1;
}
// Now one strong byte
getdrv(state->table, keylen, normal, ausreisser);
for (i = 0; i < keylen-1; i++) {
helper[i].keybyte = i+1;
helper[i].difference = normal[i+1] - ausreisser[i+1];
}
qsort(helper, keylen-1, sizeof(doublesorthelper), &comparedoublesorthelper);
strongbytes[helper[0].keybyte] = 1;
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, onestrong)) {
return 1;
}
// two strong bytes
strongbytes[helper[1].keybyte] = 1;
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, twostrong)) {
return 1;
}
return 0;
}
/*
* Guess which key bytes could be strong and start actual computation of the key
*/
int PTW_computeKey(PTW_attackstate * state, unsigned char * keybuf, int keylen, int testlimit, int * bf, int validchars[][n], int attacks) {
int strongbytes[PTW_KEYHSBYTES];
double normal[PTW_KEYHSBYTES];
double ausreisser[PTW_KEYHSBYTES];
doublesorthelper helper[PTW_KEYHSBYTES];
int simple, onestrong, twostrong;
int i,j;
unsigned char fullkeybuf[PTW_KSBYTES];
unsigned char guessbuf[PTW_KSBYTES];
sorthelper(*sh)[n-1];
PTW_tableentry (*table)[n] = (PTW_tableentry (*)[n])alloca(sizeof(PTW_tableentry) * n * keylen);
tried=0;
sh = NULL;
if (table == NULL) {
printf("could not allocate memory\n");
exit(-1);
}
if(!(attacks & NO_KLEIN))
{
// Try the original klein attack first
for (i = 0; i < keylen; i++) {
memset(&table[i][0], 0, sizeof(PTW_tableentry) * n);
for (j = 0; j < n; j++) {
table[i][j].b = j;
}
for (j = 0; j < state->packets_collected; j++) {
// fullkeybuf[0] = state->allsessions[j].iv[0];
memcpy(fullkeybuf, state->allsessions[j].iv, 3 * sizeof(unsigned char));
guesskeybytes(i+3, fullkeybuf, state->allsessions[j].keystream, guessbuf, 1);
table[i][guessbuf[0]].votes += state->allsessions[j].weight;
}
qsort(&table[i][0], n, sizeof(PTW_tableentry), &compare);
j = 0;
while(!validchars[i][table[i][j].b]) {
j++;
}
// printf("guessing i = %d, b = %d\n", i, table[0][0].b);
fullkeybuf[i+3] = table[i][j].b;
}
if (correct(state, &fullkeybuf[3], keylen)) {
memcpy(keybuf, &fullkeybuf[3], keylen * sizeof(unsigned char));
// printf("hit without correction\n");
return 1;
}
}
if(!(attacks & NO_PTW))
{
memcpy(table, state->table, sizeof(PTW_tableentry) * n * keylen);
onestrong = (testlimit/10)*2;
twostrong = (testlimit/10)*1;
simple = testlimit - onestrong - twostrong;
// now, sort the table
for (i = 0; i < keylen; i++) {
qsort(&table[i][0], n, sizeof(PTW_tableentry), &compare);
strongbytes[i] = 0;
}
sh = (sorthelper(*)[n-1])alloca(sizeof(sorthelper) * (n-1) * keylen);
if (sh == NULL) {
printf("could not allocate memory\n");
exit(-1);
}
for (i = 0; i < keylen; i++) {
for (j = 1; j < n; j++) {
sh[i][j-1].distance = table[i][0].votes - table[i][j].votes;
sh[i][j-1].value = table[i][j].b;
sh[i][j-1].keybyte = i;
}
}
qsort(sh, (n-1)*keylen, sizeof(sorthelper), &comparesorthelper);
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, simple, bf, validchars)) {
return 1;
}
// Now one strong byte
getdrv(state->table, keylen, normal, ausreisser);
for (i = 0; i < keylen-1; i++) {
helper[i].keybyte = i+1;
helper[i].difference = normal[i+1] - ausreisser[i+1];
}
qsort(helper, keylen-1, sizeof(doublesorthelper), &comparedoublesorthelper);
// do not use bf-bytes as strongbytes
i = 0;
while(bf[helper[i].keybyte] == 1) {
i++;
}
strongbytes[helper[i].keybyte] = 1;
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, onestrong, bf, validchars)) {
return 1;
}
// two strong bytes
i++;
while(bf[helper[i].keybyte] == 1) {
i++;
}
strongbytes[helper[i].keybyte] = 1;
if (doComputation(state, keybuf, keylen, table, (sorthelper *) sh, strongbytes, twostrong, bf, validchars)) {
return 1;
}
}
return 0;
}
