-- MHS 2015
**/
+/**
+
+ The runtime of opt_doTagMAC_2() with the MHS optimized version was 403 microseconds on Proxmark3.
+ This was still to slow for some newer readers which didn't want to wait that long.
+
+ Further optimizations to speedup the MAC calculations:
+ * Optimized opt_Tt logic
+ * Look up table for opt_select
+ * Removing many unnecessary bit maskings (& 0x1)
+ * updating state in place instead of alternating use of a second state structure
+ * remove the necessity to reverse bits of input and output bytes
+
+ opt_doTagMAC_2() now completes in 270 microseconds.
+
+ -- piwi 2019
+**/
+
#include "optimized_cipher.h"
#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>
-
-
-#define opt_T(s) (0x1 & ((s->t >> 15) ^ (s->t >> 14)^ (s->t >> 10)^ (s->t >> 8)^ (s->t >> 5)^ (s->t >> 4)^ (s->t >> 1)^ s->t))
-
-#define opt_B(s) (((s->b >> 6) ^ (s->b >> 5) ^ (s->b >> 4) ^ (s->b)) & 0x1)
+#include "string.h"
+
+static const uint8_t opt_select_LUT[256] = {
+ 00, 03, 02, 01, 02, 03, 00, 01, 04, 07, 07, 04, 06, 07, 05, 04,
+ 01, 02, 03, 00, 02, 03, 00, 01, 05, 06, 06, 05, 06, 07, 05, 04,
+ 06, 05, 04, 07, 04, 05, 06, 07, 06, 05, 05, 06, 04, 05, 07, 06,
+ 07, 04, 05, 06, 04, 05, 06, 07, 07, 04, 04, 07, 04, 05, 07, 06,
+ 06, 05, 04, 07, 04, 05, 06, 07, 02, 01, 01, 02, 00, 01, 03, 02,
+ 03, 00, 01, 02, 00, 01, 02, 03, 07, 04, 04, 07, 04, 05, 07, 06,
+ 00, 03, 02, 01, 02, 03, 00, 01, 00, 03, 03, 00, 02, 03, 01, 00,
+ 05, 06, 07, 04, 06, 07, 04, 05, 05, 06, 06, 05, 06, 07, 05, 04,
+ 02, 01, 00, 03, 00, 01, 02, 03, 06, 05, 05, 06, 04, 05, 07, 06,
+ 03, 00, 01, 02, 00, 01, 02, 03, 07, 04, 04, 07, 04, 05, 07, 06,
+ 02, 01, 00, 03, 00, 01, 02, 03, 02, 01, 01, 02, 00, 01, 03, 02,
+ 03, 00, 01, 02, 00, 01, 02, 03, 03, 00, 00, 03, 00, 01, 03, 02,
+ 04, 07, 06, 05, 06, 07, 04, 05, 00, 03, 03, 00, 02, 03, 01, 00,
+ 01, 02, 03, 00, 02, 03, 00, 01, 05, 06, 06, 05, 06, 07, 05, 04,
+ 04, 07, 06, 05, 06, 07, 04, 05, 04, 07, 07, 04, 06, 07, 05, 04,
+ 01, 02, 03, 00, 02, 03, 00, 01, 01, 02, 02, 01, 02, 03, 01, 00
+};
+
+/********************** the table above has been generated with this code: ********
+#include "util.h"
+static void init_opt_select_LUT(void) {
+ for (int r = 0; r < 256; r++) {
+ uint8_t r_ls2 = r << 2;
+ uint8_t r_and_ls2 = r & r_ls2;
+ uint8_t r_or_ls2 = r | r_ls2;
+ uint8_t z0 = (r_and_ls2 >> 5) ^ ((r & ~r_ls2) >> 4) ^ ( r_or_ls2 >> 3);
+ uint8_t z1 = (r_or_ls2 >> 6) ^ ( r_or_ls2 >> 1) ^ (r >> 5) ^ r;
+ uint8_t z2 = ((r & ~r_ls2) >> 4) ^ (r_and_ls2 >> 3) ^ r;
+ opt_select_LUT[r] = (z0 & 4) | (z1 & 2) | (z2 & 1);
+ }
+ print_result("", opt_select_LUT, 256);
+}
+***********************************************************************************/
#define opt__select(x,y,r) (4 & (((r & (r << 2)) >> 5) ^ ((r & ~(r << 2)) >> 4) ^ ( (r | r << 2) >> 3)))\
|(2 & (((r | r << 2) >> 6) ^ ( (r | r << 2) >> 1) ^ (r >> 5) ^ r ^ ((x^y) << 1)))\
* Some background on the expression above can be found here...
uint8_t xopt__select(bool x, bool y, uint8_t r)
{
- uint8_t r_ls2 = r << 2;
- uint8_t r_and_ls2 = r & r_ls2;
- uint8_t r_or_ls2 = r | r_ls2;
//r: r0 r1 r2 r3 r4 r5 r6 r7
//r_ls2: r2 r3 r4 r5 r6 r7 0 0
}
*/
-void opt_successor(const uint8_t *k, State *s, bool y, State *successor) {
- uint8_t Tt = 1 & opt_T(s);
-
- successor->t = (s->t >> 1);
- successor->t |= (Tt ^ (s->r >> 7 & 0x1) ^ (s->r >> 3 & 0x1)) << 15;
-
- successor->b = s->b >> 1;
- successor->b |= (opt_B(s) ^ (s->r & 0x1)) << 7;
-
- successor->r = (k[opt__select(Tt, y, s->r)] ^ successor->b) + s->l ;
- successor->l = successor->r + s->r;
+static void opt_successor(const uint8_t *k, State *s, uint8_t y) {
+// #define opt_T(s) (0x1 & ((s->t >> 15) ^ (s->t >> 14) ^ (s->t >> 10) ^ (s->t >> 8) ^ (s->t >> 5) ^ (s->t >> 4)^ (s->t >> 1) ^ s->t))
+ // uint8_t Tt = opt_T(s);
+ uint16_t Tt = s->t & 0xc533;
+ Tt = Tt ^ (Tt >> 1);
+ Tt = Tt ^ (Tt >> 4);
+ Tt = Tt ^ (Tt >> 10);
+ Tt = Tt ^ (Tt >> 8);
+
+ s->t = (s->t >> 1);
+ s->t |= (Tt ^ (s->r >> 7) ^ (s->r >> 3)) << 15;
+
+ uint8_t opt_B = s->b;
+ opt_B ^= s->b >> 6;
+ opt_B ^= s->b >> 5;
+ opt_B ^= s->b >> 4;
+
+ s->b = s->b >> 1;
+ s->b |= (opt_B ^ s->r) << 7;
+
+ uint8_t opt_select = opt_select_LUT[s->r] & 0x04;
+ opt_select |= (opt_select_LUT[s->r] ^ ((Tt ^ y) << 1)) & 0x02;
+ opt_select |= (opt_select_LUT[s->r] ^ Tt) & 0x01;
+
+ uint8_t r = s->r;
+ s->r = (k[opt_select] ^ s->b) + s->l ;
+ s->l = s->r + r;
}
-void opt_suc(const uint8_t *k, State *s, uint8_t *in, uint8_t length, bool add32Zeroes) {
- State x2;
+static void opt_suc(const uint8_t *k, State *s, uint8_t *in, uint8_t length, bool add32Zeroes) {
for (int i = 0; i < length; i++) {
uint8_t head;
- head = 1 & (in[i] >> 7);
- opt_successor(k, s, head, &x2);
+ head = in[i];
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 6);
- opt_successor(k, &x2, head, s);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 5);
- opt_successor(k, s, head, &x2);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 4);
- opt_successor(k, &x2, head, s);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 3);
- opt_successor(k, s, head, &x2);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 2);
- opt_successor(k, &x2, head, s);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & (in[i] >> 1);
- opt_successor(k, s, head, &x2);
+ head >>= 1;
+ opt_successor(k, s, head);
- head = 1 & in[i];
- opt_successor(k, &x2, head, s);
+ head >>= 1;
+ opt_successor(k, s, head);
}
//For tag MAC, an additional 32 zeroes
if (add32Zeroes) {
for(int i = 0; i < 16; i++) {
- opt_successor(k, s, 0, &x2);
- opt_successor(k, &x2, 0, s);
+ opt_successor(k, s, 0);
+ opt_successor(k, s, 0);
}
}
}
-void opt_output(const uint8_t *k, State *s, uint8_t *buffer) {
- State temp = {0, 0, 0, 0};
+static void opt_output(const uint8_t *k, State *s, uint8_t *buffer) {
for (uint8_t times = 0; times < 4; times++) {
uint8_t bout = 0;
- bout |= (s->r & 0x4) << 5;
- opt_successor(k, s, 0, &temp);
- bout |= (temp.r & 0x4) << 4;
- opt_successor(k, &temp, 0, s);
- bout |= (s->r & 0x4) << 3;
- opt_successor(k, s, 0, &temp);
- bout |= (temp.r & 0x4) << 2;
- opt_successor(k, &temp, 0, s);
- bout |= (s->r & 0x4) << 1;
- opt_successor(k, s, 0, &temp);
- bout |= (temp.r & 0x4) ;
- opt_successor(k, &temp, 0, s);
+ bout |= (s->r & 0x4) >> 2;
+ opt_successor(k, s, 0);
bout |= (s->r & 0x4) >> 1;
- opt_successor(k, s, 0, &temp);
- bout |= (temp.r & 0x4) >> 2;
- opt_successor(k, &temp, 0, s);
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4);
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4) << 1;
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4) << 2;
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4) << 3;
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4) << 4;
+ opt_successor(k, s, 0);
+ bout |= (s->r & 0x4) << 5;
+ opt_successor(k, s, 0);
buffer[times] = bout;
}
}
-void opt_MAC(uint8_t *k, uint8_t *input, uint8_t *out) {
+static void opt_MAC(uint8_t *k, uint8_t *input, uint8_t *out) {
State _init = {
((k[0] ^ 0x4c) + 0xEC) & 0xFF,// l
((k[0] ^ 0x4c) + 0x21) & 0xFF,// r
opt_output(k, &_init, out);
}
-uint8_t rev_byte(uint8_t b) {
- b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
- b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
- b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
- return b;
-}
-
-void opt_reverse_arraybytecpy(uint8_t *dest, uint8_t *src, size_t len) {
- for (size_t i = 0; i < len; i++) {
- dest[i] = rev_byte(src[i]);
- }
-}
-
void opt_doReaderMAC(uint8_t *cc_nr_p, uint8_t *div_key_p, uint8_t mac[4]) {
- static uint8_t cc_nr[12];
- opt_reverse_arraybytecpy(cc_nr, cc_nr_p, 12);
uint8_t dest[] = {0, 0, 0, 0, 0, 0, 0, 0};
- opt_MAC(div_key_p, cc_nr, dest);
- //The output MAC must also be reversed
- opt_reverse_arraybytecpy(mac, dest, 4);
+ opt_MAC(div_key_p, cc_nr_p, dest);
+ memcpy(mac, dest, 4);
return;
}
void opt_doTagMAC(uint8_t *cc_p, const uint8_t *div_key_p, uint8_t mac[4]) {
- static uint8_t cc_nr[8+4+4];
- opt_reverse_arraybytecpy(cc_nr, cc_p, 12);
State _init = {
((div_key_p[0] ^ 0x4c) + 0xEC) & 0xFF,// l
((div_key_p[0] ^ 0x4c) + 0x21) & 0xFF,// r
0x4c, // b
0xE012 // t
};
- opt_suc(div_key_p, &_init,cc_nr, 12, true);
- uint8_t dest[] = {0, 0, 0, 0};
- opt_output(div_key_p, &_init, dest);
- //The output MAC must also be reversed
- opt_reverse_arraybytecpy(mac, dest, 4);
+ opt_suc(div_key_p, &_init, cc_p, 12, true);
+ opt_output(div_key_p, &_init, mac);
return;
}
* @return the cipher state
*/
State opt_doTagMAC_1(uint8_t *cc_p, const uint8_t *div_key_p) {
- static uint8_t cc_nr[8];
- opt_reverse_arraybytecpy(cc_nr, cc_p, 8);
State _init = {
((div_key_p[0] ^ 0x4c) + 0xEC) & 0xFF,// l
((div_key_p[0] ^ 0x4c) + 0x21) & 0xFF,// r
0x4c, // b
0xE012 // t
};
- opt_suc(div_key_p, &_init, cc_nr, 8, false);
+ opt_suc(div_key_p, &_init, cc_p, 8, false);
return _init;
}
* @param div_key_p - the key to use
*/
void opt_doTagMAC_2(State _init, uint8_t *nr, uint8_t mac[4], const uint8_t *div_key_p) {
- static uint8_t _nr[4];
- opt_reverse_arraybytecpy(_nr, nr, 4);
- opt_suc(div_key_p, &_init, _nr, 4, true);
- //opt_suc(div_key_p, &_init,nr, 4, false);
- uint8_t dest[] = {0, 0, 0, 0};
- opt_output(div_key_p, &_init, dest);
- //The output MAC must also be reversed
- opt_reverse_arraybytecpy(mac, dest, 4);
+ opt_suc(div_key_p, &_init, nr, 4, true);
+ opt_output(div_key_p, &_init, mac);
return;
}
projects / proxmark3-svn / blobdiff