1*0957b409SSimon J. Gerraty /*
2*0957b409SSimon J. Gerraty * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3*0957b409SSimon J. Gerraty *
4*0957b409SSimon J. Gerraty * Permission is hereby granted, free of charge, to any person obtaining
5*0957b409SSimon J. Gerraty * a copy of this software and associated documentation files (the
6*0957b409SSimon J. Gerraty * "Software"), to deal in the Software without restriction, including
7*0957b409SSimon J. Gerraty * without limitation the rights to use, copy, modify, merge, publish,
8*0957b409SSimon J. Gerraty * distribute, sublicense, and/or sell copies of the Software, and to
9*0957b409SSimon J. Gerraty * permit persons to whom the Software is furnished to do so, subject to
10*0957b409SSimon J. Gerraty * the following conditions:
11*0957b409SSimon J. Gerraty *
12*0957b409SSimon J. Gerraty * The above copyright notice and this permission notice shall be
13*0957b409SSimon J. Gerraty * included in all copies or substantial portions of the Software.
14*0957b409SSimon J. Gerraty *
15*0957b409SSimon J. Gerraty * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*0957b409SSimon J. Gerraty * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*0957b409SSimon J. Gerraty * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*0957b409SSimon J. Gerraty * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*0957b409SSimon J. Gerraty * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*0957b409SSimon J. Gerraty * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*0957b409SSimon J. Gerraty * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*0957b409SSimon J. Gerraty * SOFTWARE.
23*0957b409SSimon J. Gerraty */
24*0957b409SSimon J. Gerraty
25*0957b409SSimon J. Gerraty #include "inner.h"
26*0957b409SSimon J. Gerraty
27*0957b409SSimon J. Gerraty /* see bearssl_block.h */
28*0957b409SSimon J. Gerraty void
br_aes_ct_cbcdec_init(br_aes_ct_cbcdec_keys * ctx,const void * key,size_t len)29*0957b409SSimon J. Gerraty br_aes_ct_cbcdec_init(br_aes_ct_cbcdec_keys *ctx,
30*0957b409SSimon J. Gerraty const void *key, size_t len)
31*0957b409SSimon J. Gerraty {
32*0957b409SSimon J. Gerraty ctx->vtable = &br_aes_ct_cbcdec_vtable;
33*0957b409SSimon J. Gerraty ctx->num_rounds = br_aes_ct_keysched(ctx->skey, key, len);
34*0957b409SSimon J. Gerraty }
35*0957b409SSimon J. Gerraty
36*0957b409SSimon J. Gerraty /* see bearssl_block.h */
37*0957b409SSimon J. Gerraty void
br_aes_ct_cbcdec_run(const br_aes_ct_cbcdec_keys * ctx,void * iv,void * data,size_t len)38*0957b409SSimon J. Gerraty br_aes_ct_cbcdec_run(const br_aes_ct_cbcdec_keys *ctx,
39*0957b409SSimon J. Gerraty void *iv, void *data, size_t len)
40*0957b409SSimon J. Gerraty {
41*0957b409SSimon J. Gerraty unsigned char *buf, *ivbuf;
42*0957b409SSimon J. Gerraty uint32_t iv0, iv1, iv2, iv3;
43*0957b409SSimon J. Gerraty uint32_t sk_exp[120];
44*0957b409SSimon J. Gerraty
45*0957b409SSimon J. Gerraty br_aes_ct_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
46*0957b409SSimon J. Gerraty ivbuf = iv;
47*0957b409SSimon J. Gerraty iv0 = br_dec32le(ivbuf);
48*0957b409SSimon J. Gerraty iv1 = br_dec32le(ivbuf + 4);
49*0957b409SSimon J. Gerraty iv2 = br_dec32le(ivbuf + 8);
50*0957b409SSimon J. Gerraty iv3 = br_dec32le(ivbuf + 12);
51*0957b409SSimon J. Gerraty buf = data;
52*0957b409SSimon J. Gerraty while (len > 0) {
53*0957b409SSimon J. Gerraty uint32_t q[8], sq[8];
54*0957b409SSimon J. Gerraty
55*0957b409SSimon J. Gerraty q[0] = br_dec32le(buf);
56*0957b409SSimon J. Gerraty q[2] = br_dec32le(buf + 4);
57*0957b409SSimon J. Gerraty q[4] = br_dec32le(buf + 8);
58*0957b409SSimon J. Gerraty q[6] = br_dec32le(buf + 12);
59*0957b409SSimon J. Gerraty if (len >= 32) {
60*0957b409SSimon J. Gerraty q[1] = br_dec32le(buf + 16);
61*0957b409SSimon J. Gerraty q[3] = br_dec32le(buf + 20);
62*0957b409SSimon J. Gerraty q[5] = br_dec32le(buf + 24);
63*0957b409SSimon J. Gerraty q[7] = br_dec32le(buf + 28);
64*0957b409SSimon J. Gerraty } else {
65*0957b409SSimon J. Gerraty q[1] = 0;
66*0957b409SSimon J. Gerraty q[3] = 0;
67*0957b409SSimon J. Gerraty q[5] = 0;
68*0957b409SSimon J. Gerraty q[7] = 0;
69*0957b409SSimon J. Gerraty }
70*0957b409SSimon J. Gerraty memcpy(sq, q, sizeof q);
71*0957b409SSimon J. Gerraty br_aes_ct_ortho(q);
72*0957b409SSimon J. Gerraty br_aes_ct_bitslice_decrypt(ctx->num_rounds, sk_exp, q);
73*0957b409SSimon J. Gerraty br_aes_ct_ortho(q);
74*0957b409SSimon J. Gerraty br_enc32le(buf, q[0] ^ iv0);
75*0957b409SSimon J. Gerraty br_enc32le(buf + 4, q[2] ^ iv1);
76*0957b409SSimon J. Gerraty br_enc32le(buf + 8, q[4] ^ iv2);
77*0957b409SSimon J. Gerraty br_enc32le(buf + 12, q[6] ^ iv3);
78*0957b409SSimon J. Gerraty if (len < 32) {
79*0957b409SSimon J. Gerraty iv0 = sq[0];
80*0957b409SSimon J. Gerraty iv1 = sq[2];
81*0957b409SSimon J. Gerraty iv2 = sq[4];
82*0957b409SSimon J. Gerraty iv3 = sq[6];
83*0957b409SSimon J. Gerraty break;
84*0957b409SSimon J. Gerraty }
85*0957b409SSimon J. Gerraty br_enc32le(buf + 16, q[1] ^ sq[0]);
86*0957b409SSimon J. Gerraty br_enc32le(buf + 20, q[3] ^ sq[2]);
87*0957b409SSimon J. Gerraty br_enc32le(buf + 24, q[5] ^ sq[4]);
88*0957b409SSimon J. Gerraty br_enc32le(buf + 28, q[7] ^ sq[6]);
89*0957b409SSimon J. Gerraty iv0 = sq[1];
90*0957b409SSimon J. Gerraty iv1 = sq[3];
91*0957b409SSimon J. Gerraty iv2 = sq[5];
92*0957b409SSimon J. Gerraty iv3 = sq[7];
93*0957b409SSimon J. Gerraty buf += 32;
94*0957b409SSimon J. Gerraty len -= 32;
95*0957b409SSimon J. Gerraty }
96*0957b409SSimon J. Gerraty br_enc32le(ivbuf, iv0);
97*0957b409SSimon J. Gerraty br_enc32le(ivbuf + 4, iv1);
98*0957b409SSimon J. Gerraty br_enc32le(ivbuf + 8, iv2);
99*0957b409SSimon J. Gerraty br_enc32le(ivbuf + 12, iv3);
100*0957b409SSimon J. Gerraty }
101*0957b409SSimon J. Gerraty
102*0957b409SSimon J. Gerraty /* see bearssl_block.h */
103*0957b409SSimon J. Gerraty const br_block_cbcdec_class br_aes_ct_cbcdec_vtable = {
104*0957b409SSimon J. Gerraty sizeof(br_aes_ct_cbcdec_keys),
105*0957b409SSimon J. Gerraty 16,
106*0957b409SSimon J. Gerraty 4,
107*0957b409SSimon J. Gerraty (void (*)(const br_block_cbcdec_class **, const void *, size_t))
108*0957b409SSimon J. Gerraty &br_aes_ct_cbcdec_init,
109*0957b409SSimon J. Gerraty (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t))
110*0957b409SSimon J. Gerraty &br_aes_ct_cbcdec_run
111*0957b409SSimon J. Gerraty };
112