common/crapto1/crypto1.c

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) 2008-2014 bla <blapost@gmail.com>
   3 // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
   4 //
   5 // This program is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // This program is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // See LICENSE.txt for the text of the license.
  16 //-----------------------------------------------------------------------------
  17 #include <stdlib.h>
  18 #include "crapto1.h"
  19 #include "parity.h"
  20
  21 #ifdef __OPTIMIZE_SIZE__
  22 int filter(uint32_t const x) {
  23     uint32_t f;
  24
  25     f  = 0xf22c0 >> (x       & 0xf) & 16;
  26     f |= 0x6c9c0 >> (x >>  4 & 0xf) &  8;
  27     f |= 0x3c8b0 >> (x >>  8 & 0xf) &  4;
  28     f |= 0x1e458 >> (x >> 12 & 0xf) &  2;
  29     f |= 0x0d938 >> (x >> 16 & 0xf) &  1;
  30     return BIT(0xEC57E80A, f);
  31 }
  32 #endif
  33
  34 #define SWAPENDIAN(x)\
  35     (x = (x >> 8 & 0xff00ff) | (x & 0xff00ff) << 8, x = x >> 16 | x << 16)
  36
  37 void crypto1_init(struct Crypto1State *state, uint64_t key) {
  38     if (state == NULL)
  39         return;
  40     state->odd = 0;
  41     state->even = 0;
  42     for (int i = 47; i > 0; i -= 2) {
  43         state->odd  = state->odd  << 1 | BIT(key, (i - 1) ^ 7);
  44         state->even = state->even << 1 | BIT(key, i ^ 7);
  45     }
  46 }
  47
  48 void crypto1_deinit(struct Crypto1State *state) {
  49     state->odd = 0;
  50     state->even = 0;
  51 }
  52
  53 #if !defined(__arm__) || defined(__linux__) || defined(_WIN32) || defined(__APPLE__) // bare metal ARM Proxmark lacks calloc()/free()
  54 struct Crypto1State *crypto1_create(uint64_t key) {
  55     struct Crypto1State *state = calloc(sizeof(*state), sizeof(uint8_t));
  56     if (!state) return NULL;
  57     crypto1_init(state, key);
  58     return state;
  59 }
  60
  61 void crypto1_destroy(struct Crypto1State *state) {
  62     free(state);
  63 }
  64 #endif
  65
  66 void crypto1_get_lfsr(struct Crypto1State *state, uint64_t *lfsr) {
  67     int i;
  68     for (*lfsr = 0, i = 23; i >= 0; --i) {
  69         *lfsr = *lfsr << 1 | BIT(state->odd, i ^ 3);
  70         *lfsr = *lfsr << 1 | BIT(state->even, i ^ 3);
  71     }
  72 }
  73 uint8_t crypto1_bit(struct Crypto1State *s, uint8_t in, int is_encrypted) {
  74     uint32_t feedin, t;
  75     uint8_t ret = filter(s->odd);
  76
  77     feedin  = ret & (!!is_encrypted);
  78     feedin ^= !!in;
  79     feedin ^= LF_POLY_ODD & s->odd;
  80     feedin ^= LF_POLY_EVEN & s->even;
  81     s->even = s->even << 1 | (evenparity32(feedin));
  82
  83     t = s->odd;
  84     s->odd = s->even;
  85     s->even = t;
  86
  87     return ret;
  88 }
  89 uint8_t crypto1_byte(struct Crypto1State *s, uint8_t in, int is_encrypted) {
  90     uint8_t ret = 0;
  91     ret |= crypto1_bit(s, BIT(in, 0), is_encrypted) << 0;
  92     ret |= crypto1_bit(s, BIT(in, 1), is_encrypted) << 1;
  93     ret |= crypto1_bit(s, BIT(in, 2), is_encrypted) << 2;
  94     ret |= crypto1_bit(s, BIT(in, 3), is_encrypted) << 3;
  95     ret |= crypto1_bit(s, BIT(in, 4), is_encrypted) << 4;
  96     ret |= crypto1_bit(s, BIT(in, 5), is_encrypted) << 5;
  97     ret |= crypto1_bit(s, BIT(in, 6), is_encrypted) << 6;
  98     ret |= crypto1_bit(s, BIT(in, 7), is_encrypted) << 7;
  99     return ret;
 100 }
 101 uint32_t crypto1_word(struct Crypto1State *s, uint32_t in, int is_encrypted) {
 102     uint32_t ret = 0;
 103     // note: xor args have been swapped because some compilers emit a warning
 104     // for 10^x and 2^x as possible misuses for exponentiation. No comment.
 105     ret |= crypto1_bit(s, BEBIT(in, 0), is_encrypted) << (24 ^ 0);
 106     ret |= crypto1_bit(s, BEBIT(in, 1), is_encrypted) << (24 ^ 1);
 107     ret |= crypto1_bit(s, BEBIT(in, 2), is_encrypted) << (24 ^ 2);
 108     ret |= crypto1_bit(s, BEBIT(in, 3), is_encrypted) << (24 ^ 3);
 109     ret |= crypto1_bit(s, BEBIT(in, 4), is_encrypted) << (24 ^ 4);
 110     ret |= crypto1_bit(s, BEBIT(in, 5), is_encrypted) << (24 ^ 5);
 111     ret |= crypto1_bit(s, BEBIT(in, 6), is_encrypted) << (24 ^ 6);
 112     ret |= crypto1_bit(s, BEBIT(in, 7), is_encrypted) << (24 ^ 7);
 113
 114     ret |= crypto1_bit(s, BEBIT(in, 8), is_encrypted) << (24 ^ 8);
 115     ret |= crypto1_bit(s, BEBIT(in, 9), is_encrypted) << (24 ^ 9);
 116     ret |= crypto1_bit(s, BEBIT(in, 10), is_encrypted) << (24 ^ 10);
 117     ret |= crypto1_bit(s, BEBIT(in, 11), is_encrypted) << (24 ^ 11);
 118     ret |= crypto1_bit(s, BEBIT(in, 12), is_encrypted) << (24 ^ 12);
 119     ret |= crypto1_bit(s, BEBIT(in, 13), is_encrypted) << (24 ^ 13);
 120     ret |= crypto1_bit(s, BEBIT(in, 14), is_encrypted) << (24 ^ 14);
 121     ret |= crypto1_bit(s, BEBIT(in, 15), is_encrypted) << (24 ^ 15);
 122
 123     ret |= crypto1_bit(s, BEBIT(in, 16), is_encrypted) << (24 ^ 16);
 124     ret |= crypto1_bit(s, BEBIT(in, 17), is_encrypted) << (24 ^ 17);
 125     ret |= crypto1_bit(s, BEBIT(in, 18), is_encrypted) << (24 ^ 18);
 126     ret |= crypto1_bit(s, BEBIT(in, 19), is_encrypted) << (24 ^ 19);
 127     ret |= crypto1_bit(s, BEBIT(in, 20), is_encrypted) << (24 ^ 20);
 128     ret |= crypto1_bit(s, BEBIT(in, 21), is_encrypted) << (24 ^ 21);
 129     ret |= crypto1_bit(s, BEBIT(in, 22), is_encrypted) << (24 ^ 22);
 130     ret |= crypto1_bit(s, BEBIT(in, 23), is_encrypted) << (24 ^ 23);
 131
 132     ret |= crypto1_bit(s, BEBIT(in, 24), is_encrypted) << (24 ^ 24);
 133     ret |= crypto1_bit(s, BEBIT(in, 25), is_encrypted) << (24 ^ 25);
 134     ret |= crypto1_bit(s, BEBIT(in, 26), is_encrypted) << (24 ^ 26);
 135     ret |= crypto1_bit(s, BEBIT(in, 27), is_encrypted) << (24 ^ 27);
 136     ret |= crypto1_bit(s, BEBIT(in, 28), is_encrypted) << (24 ^ 28);
 137     ret |= crypto1_bit(s, BEBIT(in, 29), is_encrypted) << (24 ^ 29);
 138     ret |= crypto1_bit(s, BEBIT(in, 30), is_encrypted) << (24 ^ 30);
 139     ret |= crypto1_bit(s, BEBIT(in, 31), is_encrypted) << (24 ^ 31);
 140     return ret;
 141 }
 142
 143 /* prng_successor
 144  * helper used to obscure the keystream during authentication
 145  */
 146 uint32_t prng_successor(uint32_t x, uint32_t n) {
 147     SWAPENDIAN(x);
 148     while (n--)
 149         x = x >> 1 | (x >> 16 ^ x >> 18 ^ x >> 19 ^ x >> 21) << 31;
 150
 151     return SWAPENDIAN(x);
 152 }