lilliput-ae-reference-implementation

Implementations of Lilliput-AE submitted to the NIST LWC standardization process
git clone https://git.kevinlegouguec.net/lilliput-ae-reference-implementation
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tweakey.c (1887B)

      1 /*
      2 Implementation of the Lilliput-AE tweakable block cipher.
      3 
      4 Authors, hereby denoted as "the implementer":
      5     Kévin Le Gouguec,
      6     2019.
      7 
      8 For more information, feedback or questions, refer to our website:
      9 https://paclido.fr/lilliput-ae
     10 
     11 To the extent possible under law, the implementer has waived all copyright
     12 and related or neighboring rights to the source code in this file.
     13 http://creativecommons.org/publicdomain/zero/1.0/
     14 
     15 ---
     16 
     17 This file provides the implementation of Lilliput-TBC's tweakey schedule.
     18 */
     19 
     20 #include <stdint.h>
     21 #include <string.h>
     22 
     23 #include "constants.h"
     24 #include "multiplications.h"
     25 #include "tweakey.h"
     26 
     27 
     28 #define LANES_NB (TWEAKEY_BYTES/LANE_BYTES)
     29 
     30 
     31 void tweakey_state_init(
     32     uint8_t TK[TWEAKEY_BYTES],
     33     const uint8_t key[KEY_BYTES],
     34     const uint8_t tweak[TWEAK_BYTES]
     35 )
     36 {
     37     memcpy(TK,             tweak, TWEAK_BYTES);
     38     memcpy(TK+TWEAK_BYTES, key,   KEY_BYTES);
     39 }
     40 
     41 
     42 void tweakey_state_extract(
     43     const uint8_t TK[TWEAKEY_BYTES],
     44     uint8_t round_constant,
     45     uint8_t round_tweakey[ROUND_TWEAKEY_BYTES]
     46 )
     47 {
     48     memset(round_tweakey, 0, ROUND_TWEAKEY_BYTES);
     49 
     50     for (size_t j=0; j<LANES_NB; j++)
     51     {
     52         const uint8_t *TKj = TK + j*LANE_BYTES;
     53 
     54         for (size_t k=0; k<LANE_BYTES; k++)
     55         {
     56             round_tweakey[k] ^= TKj[k];
     57         }
     58     }
     59 
     60     round_tweakey[0] ^= round_constant;
     61 }
     62 
     63 
     64 typedef void (*matrix_multiplication)(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES]);
     65 
     66 static const matrix_multiplication ALPHAS[7] = {
     67     _multiply_M,
     68     _multiply_M2,
     69     _multiply_M3,
     70     _multiply_M4,
     71     _multiply_MR,
     72     _multiply_MR2,
     73     _multiply_MR3
     74 };
     75 
     76 
     77 void tweakey_state_update(uint8_t TK[TWEAKEY_BYTES])
     78 {
     79     for (size_t j=0; j<LANES_NB; j++)
     80     {
     81         uint8_t *TKj = TK + j*LANE_BYTES;
     82 
     83         uint8_t TKj_old[LANE_BYTES];
     84         memcpy(TKj_old, TKj, LANE_BYTES);
     85 
     86         ALPHAS[j](TKj_old, TKj);
     87     }
     88 }