mirror of
https://github.com/RfidResearchGroup/proxmark3.git
synced 2024-11-11 01:55:38 +08:00
267 lines
8.8 KiB
C
267 lines
8.8 KiB
C
/*****************************************************************************
|
|
* WARNING
|
|
*
|
|
* THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.
|
|
*
|
|
* USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL
|
|
* PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,
|
|
* AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.
|
|
*
|
|
* THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.
|
|
*
|
|
*****************************************************************************
|
|
*
|
|
* This file is part of loclass. It is a reconstructon of the cipher engine
|
|
* used in iClass, and RFID techology.
|
|
*
|
|
* The implementation is based on the work performed by
|
|
* Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
|
|
* Milosch Meriac in the paper "Dismantling IClass".
|
|
*
|
|
* Copyright (C) 2014 Martin Holst Swende
|
|
*
|
|
* This is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as published
|
|
* by the Free Software Foundation, or, at your option, any later version.
|
|
*
|
|
* This file is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with loclass. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*
|
|
*
|
|
****************************************************************************/
|
|
|
|
/**
|
|
|
|
This file contains an optimized version of the MAC-calculation algorithm. Some measurements on
|
|
a std laptop showed it runs in about 1/3 of the time:
|
|
|
|
Std: 0.428962
|
|
Opt: 0.151609
|
|
|
|
Additionally, it is self-reliant, not requiring e.g. bitstreams from the cipherutils, thus can
|
|
be easily dropped into a code base.
|
|
|
|
The optimizations have been performed in the following steps:
|
|
* Parameters passed by reference instead of by value.
|
|
* Iteration instead of recursion, un-nesting recursive loops into for-loops.
|
|
* Handling of bytes instead of individual bits, for less shuffling and masking
|
|
* Less creation of "objects", structs, and instead reuse of alloc:ed memory
|
|
* Inlining some functions via #define:s
|
|
|
|
As a consequence, this implementation is less generic. Also, I haven't bothered documenting this.
|
|
For a thorough documentation, check out the MAC-calculation within cipher.c instead.
|
|
|
|
-- MHS 2015
|
|
**/
|
|
|
|
#include "optimized_cipher.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)
|
|
|
|
#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)))\
|
|
|(1 & (((r & ~(r << 2)) >> 4) ^ ((r & (r << 2)) >> 3) ^ r ^ x))
|
|
|
|
/*
|
|
* 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
|
|
// z0
|
|
// z1
|
|
|
|
// uint8_t z0 = (r0 & r2) ^ (r1 & ~r3) ^ (r2 | r4); // <-- original
|
|
uint8_t z0 = (r_and_ls2 >> 5) ^ ((r & ~r_ls2) >> 4) ^ ( r_or_ls2 >> 3);
|
|
|
|
// uint8_t z1 = (r0 | r2) ^ ( r5 | r7) ^ r1 ^ r6 ^ x ^ y; // <-- original
|
|
uint8_t z1 = (r_or_ls2 >> 6) ^ ( r_or_ls2 >> 1) ^ (r >> 5) ^ r ^ ((x^y) << 1);
|
|
|
|
// uint8_t z2 = (r3 & ~r5) ^ (r4 & r6 ) ^ r7 ^ x; // <-- original
|
|
uint8_t z2 = ((r & ~r_ls2) >> 4) ^ (r_and_ls2 >> 3) ^ r ^ x;
|
|
|
|
return (z0 & 4) | (z1 & 2) | (z2 & 1);
|
|
}
|
|
*/
|
|
|
|
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;
|
|
}
|
|
|
|
void opt_suc(const uint8_t *k, State *s, uint8_t *in, uint8_t length, bool add32Zeroes) {
|
|
State x2;
|
|
int i;
|
|
uint8_t head = 0;
|
|
for (i = 0; i < length; i++) {
|
|
head = 1 & (in[i] >> 7);
|
|
opt_successor(k, s, head, &x2);
|
|
|
|
head = 1 & (in[i] >> 6);
|
|
opt_successor(k, &x2, head, s);
|
|
|
|
head = 1 & (in[i] >> 5);
|
|
opt_successor(k, s, head, &x2);
|
|
|
|
head = 1 & (in[i] >> 4);
|
|
opt_successor(k, &x2, head, s);
|
|
|
|
head = 1 & (in[i] >> 3);
|
|
opt_successor(k, s, head, &x2);
|
|
|
|
head = 1 & (in[i] >> 2);
|
|
opt_successor(k, &x2, head, s);
|
|
|
|
head = 1 & (in[i] >> 1);
|
|
opt_successor(k, s, head, &x2);
|
|
|
|
head = 1 & in[i];
|
|
opt_successor(k, &x2, head, s);
|
|
}
|
|
|
|
//For tag MAC, an additional 32 zeroes
|
|
if (add32Zeroes) {
|
|
for (i = 0; i < 16; i++) {
|
|
opt_successor(k, s, 0, &x2);
|
|
opt_successor(k, &x2, 0, s);
|
|
}
|
|
}
|
|
}
|
|
|
|
void opt_output(const uint8_t *k, State *s, uint8_t *buffer) {
|
|
uint8_t times = 0;
|
|
uint8_t bout = 0;
|
|
State temp = {0, 0, 0, 0};
|
|
for (; times < 4; times++) {
|
|
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) >> 1;
|
|
opt_successor(k, s, 0, &temp);
|
|
bout |= (temp.r & 0x4) >> 2;
|
|
opt_successor(k, &temp, 0, s);
|
|
buffer[times] = bout;
|
|
}
|
|
}
|
|
|
|
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
|
|
0x4c, // b
|
|
0xE012 // t
|
|
};
|
|
|
|
opt_suc(k, &_init, input, 12, false);
|
|
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) {
|
|
uint8_t i;
|
|
for (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);
|
|
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);
|
|
return;
|
|
|
|
}
|
|
/**
|
|
* The tag MAC can be divided (both can, but no point in dividing the reader mac) into
|
|
* two functions, since the first 8 bytes are known, we can pre-calculate the state
|
|
* reached after feeding CC to the cipher.
|
|
* @param cc_p
|
|
* @param div_key_p
|
|
* @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);
|
|
return _init;
|
|
}
|
|
/**
|
|
* The second part of the tag MAC calculation, since the CC is already calculated into the state,
|
|
* this function is fed only the NR, and internally feeds the remaining 32 0-bits to generate the tag
|
|
* MAC response.
|
|
* @param _init - precalculated cipher state
|
|
* @param nr - the reader challenge
|
|
* @param mac - where to store the MAC
|
|
* @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);
|
|
|
|
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);
|
|
return;
|
|
}
|