1/*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25#include "inner.h"
26
27/* see inner.h */
28void
29br_aes_ct64_bitslice_invSbox(uint64_t *q)
30{
31	/*
32	 * See br_aes_ct_bitslice_invSbox(). This is the natural extension
33	 * to 64-bit registers.
34	 */
35	uint64_t q0, q1, q2, q3, q4, q5, q6, q7;
36
37	q0 = ~q[0];
38	q1 = ~q[1];
39	q2 = q[2];
40	q3 = q[3];
41	q4 = q[4];
42	q5 = ~q[5];
43	q6 = ~q[6];
44	q7 = q[7];
45	q[7] = q1 ^ q4 ^ q6;
46	q[6] = q0 ^ q3 ^ q5;
47	q[5] = q7 ^ q2 ^ q4;
48	q[4] = q6 ^ q1 ^ q3;
49	q[3] = q5 ^ q0 ^ q2;
50	q[2] = q4 ^ q7 ^ q1;
51	q[1] = q3 ^ q6 ^ q0;
52	q[0] = q2 ^ q5 ^ q7;
53
54	br_aes_ct64_bitslice_Sbox(q);
55
56	q0 = ~q[0];
57	q1 = ~q[1];
58	q2 = q[2];
59	q3 = q[3];
60	q4 = q[4];
61	q5 = ~q[5];
62	q6 = ~q[6];
63	q7 = q[7];
64	q[7] = q1 ^ q4 ^ q6;
65	q[6] = q0 ^ q3 ^ q5;
66	q[5] = q7 ^ q2 ^ q4;
67	q[4] = q6 ^ q1 ^ q3;
68	q[3] = q5 ^ q0 ^ q2;
69	q[2] = q4 ^ q7 ^ q1;
70	q[1] = q3 ^ q6 ^ q0;
71	q[0] = q2 ^ q5 ^ q7;
72}
73
74static void
75add_round_key(uint64_t *q, const uint64_t *sk)
76{
77	int i;
78
79	for (i = 0; i < 8; i ++) {
80		q[i] ^= sk[i];
81	}
82}
83
84static void
85inv_shift_rows(uint64_t *q)
86{
87	int i;
88
89	for (i = 0; i < 8; i ++) {
90		uint64_t x;
91
92		x = q[i];
93		q[i] = (x & (uint64_t)0x000000000000FFFF)
94			| ((x & (uint64_t)0x000000000FFF0000) << 4)
95			| ((x & (uint64_t)0x00000000F0000000) >> 12)
96			| ((x & (uint64_t)0x000000FF00000000) << 8)
97			| ((x & (uint64_t)0x0000FF0000000000) >> 8)
98			| ((x & (uint64_t)0x000F000000000000) << 12)
99			| ((x & (uint64_t)0xFFF0000000000000) >> 4);
100	}
101}
102
103static inline uint64_t
104rotr32(uint64_t x)
105{
106	return (x << 32) | (x >> 32);
107}
108
109static void
110inv_mix_columns(uint64_t *q)
111{
112	uint64_t q0, q1, q2, q3, q4, q5, q6, q7;
113	uint64_t r0, r1, r2, r3, r4, r5, r6, r7;
114
115	q0 = q[0];
116	q1 = q[1];
117	q2 = q[2];
118	q3 = q[3];
119	q4 = q[4];
120	q5 = q[5];
121	q6 = q[6];
122	q7 = q[7];
123	r0 = (q0 >> 16) | (q0 << 48);
124	r1 = (q1 >> 16) | (q1 << 48);
125	r2 = (q2 >> 16) | (q2 << 48);
126	r3 = (q3 >> 16) | (q3 << 48);
127	r4 = (q4 >> 16) | (q4 << 48);
128	r5 = (q5 >> 16) | (q5 << 48);
129	r6 = (q6 >> 16) | (q6 << 48);
130	r7 = (q7 >> 16) | (q7 << 48);
131
132	q[0] = q5 ^ q6 ^ q7 ^ r0 ^ r5 ^ r7 ^ rotr32(q0 ^ q5 ^ q6 ^ r0 ^ r5);
133	q[1] = q0 ^ q5 ^ r0 ^ r1 ^ r5 ^ r6 ^ r7 ^ rotr32(q1 ^ q5 ^ q7 ^ r1 ^ r5 ^ r6);
134	q[2] = q0 ^ q1 ^ q6 ^ r1 ^ r2 ^ r6 ^ r7 ^ rotr32(q0 ^ q2 ^ q6 ^ r2 ^ r6 ^ r7);
135	q[3] = q0 ^ q1 ^ q2 ^ q5 ^ q6 ^ r0 ^ r2 ^ r3 ^ r5 ^ rotr32(q0 ^ q1 ^ q3 ^ q5 ^ q6 ^ q7 ^ r0 ^ r3 ^ r5 ^ r7);
136	q[4] = q1 ^ q2 ^ q3 ^ q5 ^ r1 ^ r3 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr32(q1 ^ q2 ^ q4 ^ q5 ^ q7 ^ r1 ^ r4 ^ r5 ^ r6);
137	q[5] = q2 ^ q3 ^ q4 ^ q6 ^ r2 ^ r4 ^ r5 ^ r6 ^ r7 ^ rotr32(q2 ^ q3 ^ q5 ^ q6 ^ r2 ^ r5 ^ r6 ^ r7);
138	q[6] = q3 ^ q4 ^ q5 ^ q7 ^ r3 ^ r5 ^ r6 ^ r7 ^ rotr32(q3 ^ q4 ^ q6 ^ q7 ^ r3 ^ r6 ^ r7);
139	q[7] = q4 ^ q5 ^ q6 ^ r4 ^ r6 ^ r7 ^ rotr32(q4 ^ q5 ^ q7 ^ r4 ^ r7);
140}
141
142/* see inner.h */
143void
144br_aes_ct64_bitslice_decrypt(unsigned num_rounds,
145	const uint64_t *skey, uint64_t *q)
146{
147	unsigned u;
148
149	add_round_key(q, skey + (num_rounds << 3));
150	for (u = num_rounds - 1; u > 0; u --) {
151		inv_shift_rows(q);
152		br_aes_ct64_bitslice_invSbox(q);
153		add_round_key(q, skey + (u << 3));
154		inv_mix_columns(q);
155	}
156	inv_shift_rows(q);
157	br_aes_ct64_bitslice_invSbox(q);
158	add_round_key(q, skey);
159}
160