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_ct64_cbcdec_init(br_aes_ct64_cbcdec_keys *ctx, 30 const void *key, size_t len) 31 { 32 ctx->vtable = &br_aes_ct64_cbcdec_vtable; 33 ctx->num_rounds = br_aes_ct64_keysched(ctx->skey, key, len); 34 } 35 36 /* see bearssl_block.h */ 37 void 38 br_aes_ct64_cbcdec_run(const br_aes_ct64_cbcdec_keys *ctx, 39 void *iv, void *data, size_t len) 40 { 41 unsigned char *buf; 42 uint64_t sk_exp[120]; 43 uint32_t ivw[4]; 44 45 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey); 46 br_range_dec32le(ivw, 4, iv); 47 buf = data; 48 while (len > 0) { 49 uint64_t q[8]; 50 uint32_t w1[16], w2[16]; 51 int i; 52 53 if (len >= 64) { 54 br_range_dec32le(w1, 16, buf); 55 } else { 56 br_range_dec32le(w1, len >> 2, buf); 57 } 58 for (i = 0; i < 4; i ++) { 59 br_aes_ct64_interleave_in( 60 &q[i], &q[i + 4], w1 + (i << 2)); 61 } 62 br_aes_ct64_ortho(q); 63 br_aes_ct64_bitslice_decrypt(ctx->num_rounds, sk_exp, q); 64 br_aes_ct64_ortho(q); 65 for (i = 0; i < 4; i ++) { 66 br_aes_ct64_interleave_out( 67 w2 + (i << 2), q[i], q[i + 4]); 68 } 69 for (i = 0; i < 4; i ++) { 70 w2[i] ^= ivw[i]; 71 } 72 if (len >= 64) { 73 for (i = 4; i < 16; i ++) { 74 w2[i] ^= w1[i - 4]; 75 } 76 memcpy(ivw, w1 + 12, sizeof ivw); 77 br_range_enc32le(buf, w2, 16); 78 } else { 79 int j; 80 81 j = (int)(len >> 2); 82 for (i = 4; i < j; i ++) { 83 w2[i] ^= w1[i - 4]; 84 } 85 memcpy(ivw, w1 + j - 4, sizeof ivw); 86 br_range_enc32le(buf, w2, j); 87 break; 88 } 89 buf += 64; 90 len -= 64; 91 } 92 br_range_enc32le(iv, ivw, 4); 93 } 94 95 /* see bearssl_block.h */ 96 const br_block_cbcdec_class br_aes_ct64_cbcdec_vtable = { 97 sizeof(br_aes_ct64_cbcdec_keys), 98 16, 99 4, 100 (void (*)(const br_block_cbcdec_class **, const void *, size_t)) 101 &br_aes_ct64_cbcdec_init, 102 (void (*)(const br_block_cbcdec_class *const *, void *, void *, size_t)) 103 &br_aes_ct64_cbcdec_run 104 }; 105