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 bearssl_block.h */ 28 void 29 br_aes_big_cbcdec_init(br_aes_big_cbcdec_keys *ctx, 30 const void *key, size_t len) 31 { 32 ctx->vtable = &br_aes_big_cbcdec_vtable; 33 ctx->num_rounds = br_aes_big_keysched_inv(ctx->skey, key, len); 34 } 35 36 /* see bearssl_block.h */ 37 void 38 br_aes_big_cbcdec_run(const br_aes_big_cbcdec_keys *ctx, 39 void *iv, void *data, size_t len) 40 { 41 unsigned char *buf, *ivbuf; 42 43 ivbuf = iv; 44 buf = data; 45 while (len > 0) { 46 unsigned char tmp[16]; 47 int i; 48 49 memcpy(tmp, buf, 16); 50 br_aes_big_decrypt(ctx->num_rounds, ctx->skey, buf); 51 for (i = 0; i < 16; i ++) { 52 buf[i] ^= ivbuf[i]; 53 } 54 memcpy(ivbuf, tmp, 16); 55 buf += 16; 56 len -= 16; 57 } 58 } 59 60 /* see bearssl_block.h */ 61 const br_block_cbcdec_class br_aes_big_cbcdec_vtable = { 62 sizeof(br_aes_big_cbcdec_keys), 63 16, 64 4, 65 (void (*)(const br_block_cbcdec_class **, const void *, size_t)) 66 &br_aes_big_cbcdec_init, 67 (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t)) 68 &br_aes_big_cbcdec_run 69 }; 70