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      1 /*	$NetBSD: aes_ct_enc.c,v 1.1 2020/06/29 23:27:52 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2016 Thomas Pornin <pornin (at) bolet.org>
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining
      7  * a copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sublicense, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be
     15  * included in all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     18  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     19  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     20  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     21  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     22  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     23  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     24  * SOFTWARE.
     25  */
     26 
     27 #include <sys/cdefs.h>
     28 __KERNEL_RCSID(1, "$NetBSD: aes_ct_enc.c,v 1.1 2020/06/29 23:27:52 riastradh Exp $");
     29 
     30 #include <sys/types.h>
     31 
     32 #include <crypto/aes/aes_bear.h>
     33 
     34 static inline void
     35 add_round_key(uint32_t *q, const uint32_t *sk)
     36 {
     37 	q[0] ^= sk[0];
     38 	q[1] ^= sk[1];
     39 	q[2] ^= sk[2];
     40 	q[3] ^= sk[3];
     41 	q[4] ^= sk[4];
     42 	q[5] ^= sk[5];
     43 	q[6] ^= sk[6];
     44 	q[7] ^= sk[7];
     45 }
     46 
     47 static inline void
     48 shift_rows(uint32_t *q)
     49 {
     50 	int i;
     51 
     52 	for (i = 0; i < 8; i ++) {
     53 		uint32_t x;
     54 
     55 		x = q[i];
     56 		q[i] = (x & 0x000000FF)
     57 			| ((x & 0x0000FC00) >> 2) | ((x & 0x00000300) << 6)
     58 			| ((x & 0x00F00000) >> 4) | ((x & 0x000F0000) << 4)
     59 			| ((x & 0xC0000000) >> 6) | ((x & 0x3F000000) << 2);
     60 	}
     61 }
     62 
     63 static inline uint32_t
     64 rotr16(uint32_t x)
     65 {
     66 	return (x << 16) | (x >> 16);
     67 }
     68 
     69 static inline void
     70 mix_columns(uint32_t *q)
     71 {
     72 	uint32_t q0, q1, q2, q3, q4, q5, q6, q7;
     73 	uint32_t r0, r1, r2, r3, r4, r5, r6, r7;
     74 
     75 	q0 = q[0];
     76 	q1 = q[1];
     77 	q2 = q[2];
     78 	q3 = q[3];
     79 	q4 = q[4];
     80 	q5 = q[5];
     81 	q6 = q[6];
     82 	q7 = q[7];
     83 	r0 = (q0 >> 8) | (q0 << 24);
     84 	r1 = (q1 >> 8) | (q1 << 24);
     85 	r2 = (q2 >> 8) | (q2 << 24);
     86 	r3 = (q3 >> 8) | (q3 << 24);
     87 	r4 = (q4 >> 8) | (q4 << 24);
     88 	r5 = (q5 >> 8) | (q5 << 24);
     89 	r6 = (q6 >> 8) | (q6 << 24);
     90 	r7 = (q7 >> 8) | (q7 << 24);
     91 
     92 	q[0] = q7 ^ r7 ^ r0 ^ rotr16(q0 ^ r0);
     93 	q[1] = q0 ^ r0 ^ q7 ^ r7 ^ r1 ^ rotr16(q1 ^ r1);
     94 	q[2] = q1 ^ r1 ^ r2 ^ rotr16(q2 ^ r2);
     95 	q[3] = q2 ^ r2 ^ q7 ^ r7 ^ r3 ^ rotr16(q3 ^ r3);
     96 	q[4] = q3 ^ r3 ^ q7 ^ r7 ^ r4 ^ rotr16(q4 ^ r4);
     97 	q[5] = q4 ^ r4 ^ r5 ^ rotr16(q5 ^ r5);
     98 	q[6] = q5 ^ r5 ^ r6 ^ rotr16(q6 ^ r6);
     99 	q[7] = q6 ^ r6 ^ r7 ^ rotr16(q7 ^ r7);
    100 }
    101 
    102 /* see inner.h */
    103 void
    104 br_aes_ct_bitslice_encrypt(unsigned num_rounds,
    105 	const uint32_t *skey, uint32_t *q)
    106 {
    107 	unsigned u;
    108 
    109 	add_round_key(q, skey);
    110 	for (u = 1; u < num_rounds; u ++) {
    111 		br_aes_ct_bitslice_Sbox(q);
    112 		shift_rows(q);
    113 		mix_columns(q);
    114 		add_round_key(q, skey + (u << 3));
    115 	}
    116 	br_aes_ct_bitslice_Sbox(q);
    117 	shift_rows(q);
    118 	add_round_key(q, skey + (num_rounds << 3));
    119 }
    120