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_ctr_init(br_aes_ct64_ctr_keys *ctx, 30 const void *key, size_t len) 31 { 32 ctx->vtable = &br_aes_ct64_ctr_vtable; 33 ctx->num_rounds = br_aes_ct64_keysched(ctx->skey, key, len); 34 } 35 36 static void 37 xorbuf(void *dst, const void *src, size_t len) 38 { 39 unsigned char *d; 40 const unsigned char *s; 41 42 d = dst; 43 s = src; 44 while (len -- > 0) { 45 *d ++ ^= *s ++; 46 } 47 } 48 49 /* see bearssl_block.h */ 50 uint32_t 51 br_aes_ct64_ctr_run(const br_aes_ct64_ctr_keys *ctx, 52 const void *iv, uint32_t cc, void *data, size_t len) 53 { 54 unsigned char *buf; 55 uint32_t ivw[16]; 56 uint64_t sk_exp[120]; 57 58 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey); 59 br_range_dec32le(ivw, 3, iv); 60 memcpy(ivw + 4, ivw, 3 * sizeof(uint32_t)); 61 memcpy(ivw + 8, ivw, 3 * sizeof(uint32_t)); 62 memcpy(ivw + 12, ivw, 3 * sizeof(uint32_t)); 63 buf = data; 64 while (len > 0) { 65 uint64_t q[8]; 66 uint32_t w[16]; 67 unsigned char tmp[64]; 68 int i; 69 70 /* 71 * TODO: see if we can save on the first br_aes_ct64_ortho() 72 * call, since iv0/iv1/iv2 are constant for the whole run. 73 */ 74 memcpy(w, ivw, sizeof ivw); 75 w[3] = br_swap32(cc); 76 w[7] = br_swap32(cc + 1); 77 w[11] = br_swap32(cc + 2); 78 w[15] = br_swap32(cc + 3); 79 for (i = 0; i < 4; i ++) { 80 br_aes_ct64_interleave_in( 81 &q[i], &q[i + 4], w + (i << 2)); 82 } 83 br_aes_ct64_ortho(q); 84 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q); 85 br_aes_ct64_ortho(q); 86 for (i = 0; i < 4; i ++) { 87 br_aes_ct64_interleave_out( 88 w + (i << 2), q[i], q[i + 4]); 89 } 90 br_range_enc32le(tmp, w, 16); 91 if (len <= 64) { 92 xorbuf(buf, tmp, len); 93 cc += (uint32_t)len >> 4; 94 break; 95 } 96 xorbuf(buf, tmp, 64); 97 buf += 64; 98 len -= 64; 99 cc += 4; 100 } 101 return cc; 102 } 103 104 /* see bearssl_block.h */ 105 const br_block_ctr_class br_aes_ct64_ctr_vtable = { 106 sizeof(br_aes_ct64_ctr_keys), 107 16, 108 4, 109 (void (*)(const br_block_ctr_class **, const void *, size_t)) 110 &br_aes_ct64_ctr_init, 111 (uint32_t (*)(const br_block_ctr_class *const *, 112 const void *, uint32_t, void *, size_t)) 113 &br_aes_ct64_ctr_run 114 }; 115