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_des_tab_cbcdec_init(br_des_tab_cbcdec_keys *ctx, 30 const void *key, size_t len) 31 { 32 ctx->vtable = &br_des_tab_cbcdec_vtable; 33 ctx->num_rounds = br_des_tab_keysched(ctx->skey, key, len); 34 if (len == 8) { 35 br_des_rev_skey(ctx->skey); 36 } else { 37 int i; 38 39 for (i = 0; i < 48; i += 2) { 40 uint32_t t; 41 42 t = ctx->skey[i]; 43 ctx->skey[i] = ctx->skey[94 - i]; 44 ctx->skey[94 - i] = t; 45 t = ctx->skey[i + 1]; 46 ctx->skey[i + 1] = ctx->skey[95 - i]; 47 ctx->skey[95 - i] = t; 48 } 49 } 50 } 51 52 /* see bearssl_block.h */ 53 void 54 br_des_tab_cbcdec_run(const br_des_tab_cbcdec_keys *ctx, 55 void *iv, void *data, size_t len) 56 { 57 unsigned char *buf, *ivbuf; 58 59 ivbuf = iv; 60 buf = data; 61 while (len > 0) { 62 unsigned char tmp[8]; 63 int i; 64 65 memcpy(tmp, buf, 8); 66 br_des_tab_process_block(ctx->num_rounds, ctx->skey, buf); 67 for (i = 0; i < 8; i ++) { 68 buf[i] ^= ivbuf[i]; 69 } 70 memcpy(ivbuf, tmp, 8); 71 buf += 8; 72 len -= 8; 73 } 74 } 75 76 /* see bearssl_block.h */ 77 const br_block_cbcdec_class br_des_tab_cbcdec_vtable = { 78 sizeof(br_des_tab_cbcdec_keys), 79 8, 80 3, 81 (void (*)(const br_block_cbcdec_class **, const void *, size_t)) 82 &br_des_tab_cbcdec_init, 83 (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t)) 84 &br_des_tab_cbcdec_run 85 }; 86