tools/hitag2crack/crack5opencl/hitag2.h

   1 #ifndef HITAG2_H
   2 #define HITAG2_H
   3
   4 #include <stdint.h>
   5 #include <stdbool.h>
   6
   7 // as the HITAG2 original implementation, with some minor changes
   8
   9 #define i4(x,a,b,c,d) ((uint32_t)((((x)>>(a))&1)<<3)|(((x)>>(b))&1)<<2|(((x)>>(c))&1)<<1|(((x)>>(d))&1))
  10 #define f(state) ((0xdd3929b >> ( (((0x3c65 >> i4(state, 2, 3, 5, 6) ) & 1) <<4) \
  11                                 | ((( 0xee5 >> i4(state, 8,12,14,15) ) & 1) <<3) \
  12                                 | ((( 0xee5 >> i4(state,17,21,23,26) ) & 1) <<2) \
  13                                 | ((( 0xee5 >> i4(state,28,29,31,33) ) & 1) <<1) \
  14                                 | (((0x3c65 >> i4(state,34,43,44,46) ) & 1) ))) & 1)
  15
  16 #define get_bit(n, word) ((word >> (n)) & 1)
  17
  18 /*
  19  * Hitag Crypto support macros
  20  * These macros reverse the bit order in a byte, or *within* each byte of a
  21  * 16 , 32 or 64 bit unsigned integer. (Not across the whole 16 etc bits.)
  22  */
  23 #define rev8(X)   ((((X) >> 7) &1) + (((X) >> 5) &2) + (((X) >> 3) &4) \
  24                   + (((X) >> 1) &8) + (((X) << 1) &16) + (((X) << 3) &32) \
  25                   + (((X) << 5) &64) + (((X) << 7) &128) )
  26 #define rev16(X)  (rev8 (X) + (rev8 (X >> 8) << 8))
  27 #define rev32(X)  (rev16(X) + (rev16(X >> 16) << 16))
  28 #define rev64(X)  (rev32(X) + (rev32(X >> 32) << 32))
  29
  30 typedef struct {
  31     uint64_t shiftreg; // naive shift register, required for nonlinear fn input
  32     uint64_t lfsr;     // fast lfsr, used to make software faster
  33 } Hitag_State;
  34
  35 // return a single bit from a value
  36 int bitn(uint64_t x, int bit);
  37
  38 // the sub-function R that rollback depends upon
  39 int fnR(uint64_t x);
  40
  41 // the three filter sub-functions that feed fnf
  42 int fa(unsigned int i);
  43
  44 int fb(unsigned int i);
  45
  46 // the filter function that generates a bit of output from the prng state
  47 int fnf(uint64_t s);
  48
  49 // macros to pick out 4 bits in various patterns of 1s & 2s & make a new number
  50 #define pickbits2_2(S, A, B)       ( ((S >> A) & 3) | ((S >> (B - 2)) & 0xC) )
  51 #define pickbits1x4(S, A, B, C, D) ( ((S >> A) & 1) | ((S >> (B - 1)) & 2) | ((S >> (C - 2)) & 4) | ((S >> (D - 3)) & 8) )
  52 #define pickbits1_1_2(S, A, B, C)  ( ((S >> A) & 1) | ((S >> (B - 1)) & 2) | ((S >> (C - 2)) & 0xC) )
  53 #define pickbits2_1_1(S, A, B, C)  ( ((S >> A) & 3) | ((S >> (B - 2)) & 4) | ((S >> (C - 3)) & 8) )
  54 #define pickbits1_2_1(S, A, B, C)  ( ((S >> A) & 1) | ((S >> (B - 1)) & 6) | ((S >> (C - 3)) & 8) )
  55
  56 uint32_t hitag2_crypt(uint64_t x);
  57
  58 /*
  59  * Return up to 32 crypto bits.
  60  * Last bit is in least significant bit, earlier bits are shifted left.
  61  * Note that the Hitag transmission protocol is least significant bit,
  62  * so we may want to change this, or add a function, that returns the
  63  * crypto output bits in the other order.
  64  *
  65  * Parameters:
  66  * Hitag_State* pstate - in/out, internal cipher state after initialisation
  67  * uint32_t steps      - number of bits requested, (capped at 32)
  68  */
  69 uint32_t hitag2_nstep(Hitag_State *pstate, uint32_t steps);
  70
  71 /*
  72  * Parameters:
  73  * Hitag_State* pstate - output, internal state after initialisation
  74  * uint64_t sharedkey  - 48 bit key shared between reader & tag
  75  * uint32_t serialnum  - 32 bit tag serial number
  76  * uint32_t initvector - 32 bit random IV from reader, part of tag authentication
  77  */
  78 void hitag2_init(Hitag_State *pstate, uint64_t sharedkey, uint32_t serialnum, uint32_t initvector);
  79
  80 // try_state
  81 bool try_state(uint64_t s, uint32_t uid, uint32_t aR2, uint32_t nR1, uint32_t nR2, uint64_t *key);
  82
  83 #endif // HITAG2_H