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 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 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