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Some documentation fixes.
[BearSSL] / src / symcipher / aes_ct64_ctrcbc.c
1 /*
2 * Copyright (c) 2017 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_ctrcbc_init(br_aes_ct64_ctrcbc_keys *ctx,
30 const void *key, size_t len)
31 {
32 ctx->vtable = &br_aes_ct64_ctrcbc_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 void
51 br_aes_ct64_ctrcbc_ctr(const br_aes_ct64_ctrcbc_keys *ctx,
52 void *ctr, void *data, size_t len)
53 {
54 unsigned char *buf;
55 unsigned char *ivbuf;
56 uint32_t iv0, iv1, iv2, iv3;
57 uint64_t sk_exp[120];
58
59 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
60
61 /*
62 * We keep the counter as four 32-bit values, with big-endian
63 * convention, because that's what is expected for purposes of
64 * incrementing the counter value.
65 */
66 ivbuf = ctr;
67 iv0 = br_dec32be(ivbuf + 0);
68 iv1 = br_dec32be(ivbuf + 4);
69 iv2 = br_dec32be(ivbuf + 8);
70 iv3 = br_dec32be(ivbuf + 12);
71
72 buf = data;
73 while (len > 0) {
74 uint64_t q[8];
75 uint32_t w[16];
76 unsigned char tmp[64];
77 int i, j;
78
79 /*
80 * The bitslice implementation expects values in
81 * little-endian convention, so we have to byteswap them.
82 */
83 j = (len >= 64) ? 16 : (int)(len >> 2);
84 for (i = 0; i < j; i += 4) {
85 uint32_t carry;
86
87 w[i + 0] = br_swap32(iv0);
88 w[i + 1] = br_swap32(iv1);
89 w[i + 2] = br_swap32(iv2);
90 w[i + 3] = br_swap32(iv3);
91 iv3 ++;
92 carry = ~(iv3 | -iv3) >> 31;
93 iv2 += carry;
94 carry &= -(~(iv2 | -iv2) >> 31);
95 iv1 += carry;
96 carry &= -(~(iv1 | -iv1) >> 31);
97 iv0 += carry;
98 }
99 memset(w + i, 0, (16 - i) * sizeof(uint32_t));
100
101 for (i = 0; i < 4; i ++) {
102 br_aes_ct64_interleave_in(
103 &q[i], &q[i + 4], w + (i << 2));
104 }
105 br_aes_ct64_ortho(q);
106 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
107 br_aes_ct64_ortho(q);
108 for (i = 0; i < 4; i ++) {
109 br_aes_ct64_interleave_out(
110 w + (i << 2), q[i], q[i + 4]);
111 }
112
113 br_range_enc32le(tmp, w, 16);
114 if (len <= 64) {
115 xorbuf(buf, tmp, len);
116 break;
117 }
118 xorbuf(buf, tmp, 64);
119 buf += 64;
120 len -= 64;
121 }
122 br_enc32be(ivbuf + 0, iv0);
123 br_enc32be(ivbuf + 4, iv1);
124 br_enc32be(ivbuf + 8, iv2);
125 br_enc32be(ivbuf + 12, iv3);
126 }
127
128 /* see bearssl_block.h */
129 void
130 br_aes_ct64_ctrcbc_mac(const br_aes_ct64_ctrcbc_keys *ctx,
131 void *cbcmac, const void *data, size_t len)
132 {
133 const unsigned char *buf;
134 uint32_t cm0, cm1, cm2, cm3;
135 uint64_t q[8];
136 uint64_t sk_exp[120];
137
138 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
139
140 cm0 = br_dec32le((unsigned char *)cbcmac + 0);
141 cm1 = br_dec32le((unsigned char *)cbcmac + 4);
142 cm2 = br_dec32le((unsigned char *)cbcmac + 8);
143 cm3 = br_dec32le((unsigned char *)cbcmac + 12);
144
145 buf = data;
146 memset(q, 0, sizeof q);
147 while (len > 0) {
148 uint32_t w[4];
149
150 w[0] = cm0 ^ br_dec32le(buf + 0);
151 w[1] = cm1 ^ br_dec32le(buf + 4);
152 w[2] = cm2 ^ br_dec32le(buf + 8);
153 w[3] = cm3 ^ br_dec32le(buf + 12);
154
155 br_aes_ct64_interleave_in(&q[0], &q[4], w);
156 br_aes_ct64_ortho(q);
157 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
158 br_aes_ct64_ortho(q);
159 br_aes_ct64_interleave_out(w, q[0], q[4]);
160
161 cm0 = w[0];
162 cm1 = w[1];
163 cm2 = w[2];
164 cm3 = w[3];
165 buf += 16;
166 len -= 16;
167 }
168
169 br_enc32le((unsigned char *)cbcmac + 0, cm0);
170 br_enc32le((unsigned char *)cbcmac + 4, cm1);
171 br_enc32le((unsigned char *)cbcmac + 8, cm2);
172 br_enc32le((unsigned char *)cbcmac + 12, cm3);
173 }
174
175 /* see bearssl_block.h */
176 void
177 br_aes_ct64_ctrcbc_encrypt(const br_aes_ct64_ctrcbc_keys *ctx,
178 void *ctr, void *cbcmac, void *data, size_t len)
179 {
180 /*
181 * When encrypting, the CBC-MAC processing must be lagging by
182 * one block, since it operates on the encrypted values, so
183 * it must wait for that encryption to complete.
184 */
185
186 unsigned char *buf;
187 unsigned char *ivbuf;
188 uint32_t iv0, iv1, iv2, iv3;
189 uint32_t cm0, cm1, cm2, cm3;
190 uint64_t sk_exp[120];
191 uint64_t q[8];
192 int first_iter;
193
194 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
195
196 /*
197 * We keep the counter as four 32-bit values, with big-endian
198 * convention, because that's what is expected for purposes of
199 * incrementing the counter value.
200 */
201 ivbuf = ctr;
202 iv0 = br_dec32be(ivbuf + 0);
203 iv1 = br_dec32be(ivbuf + 4);
204 iv2 = br_dec32be(ivbuf + 8);
205 iv3 = br_dec32be(ivbuf + 12);
206
207 /*
208 * The current CBC-MAC value is kept in little-endian convention.
209 */
210 cm0 = br_dec32le((unsigned char *)cbcmac + 0);
211 cm1 = br_dec32le((unsigned char *)cbcmac + 4);
212 cm2 = br_dec32le((unsigned char *)cbcmac + 8);
213 cm3 = br_dec32le((unsigned char *)cbcmac + 12);
214
215 buf = data;
216 first_iter = 1;
217 memset(q, 0, sizeof q);
218 while (len > 0) {
219 uint32_t w[8], carry;
220
221 /*
222 * The bitslice implementation expects values in
223 * little-endian convention, so we have to byteswap them.
224 */
225 w[0] = br_swap32(iv0);
226 w[1] = br_swap32(iv1);
227 w[2] = br_swap32(iv2);
228 w[3] = br_swap32(iv3);
229 iv3 ++;
230 carry = ~(iv3 | -iv3) >> 31;
231 iv2 += carry;
232 carry &= -(~(iv2 | -iv2) >> 31);
233 iv1 += carry;
234 carry &= -(~(iv1 | -iv1) >> 31);
235 iv0 += carry;
236
237 /*
238 * The block for CBC-MAC.
239 */
240 w[4] = cm0;
241 w[5] = cm1;
242 w[6] = cm2;
243 w[7] = cm3;
244
245 br_aes_ct64_interleave_in(&q[0], &q[4], w);
246 br_aes_ct64_interleave_in(&q[1], &q[5], w + 4);
247 br_aes_ct64_ortho(q);
248 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
249 br_aes_ct64_ortho(q);
250 br_aes_ct64_interleave_out(w, q[0], q[4]);
251 br_aes_ct64_interleave_out(w + 4, q[1], q[5]);
252
253 /*
254 * We do the XOR with the plaintext in 32-bit registers,
255 * so that the value are available for CBC-MAC processing
256 * as well.
257 */
258 w[0] ^= br_dec32le(buf + 0);
259 w[1] ^= br_dec32le(buf + 4);
260 w[2] ^= br_dec32le(buf + 8);
261 w[3] ^= br_dec32le(buf + 12);
262 br_enc32le(buf + 0, w[0]);
263 br_enc32le(buf + 4, w[1]);
264 br_enc32le(buf + 8, w[2]);
265 br_enc32le(buf + 12, w[3]);
266
267 buf += 16;
268 len -= 16;
269
270 /*
271 * We set the cm* values to the block to encrypt in the
272 * next iteration.
273 */
274 if (first_iter) {
275 first_iter = 0;
276 cm0 ^= w[0];
277 cm1 ^= w[1];
278 cm2 ^= w[2];
279 cm3 ^= w[3];
280 } else {
281 cm0 = w[0] ^ w[4];
282 cm1 = w[1] ^ w[5];
283 cm2 = w[2] ^ w[6];
284 cm3 = w[3] ^ w[7];
285 }
286
287 /*
288 * If this was the last iteration, then compute the
289 * extra block encryption to complete CBC-MAC.
290 */
291 if (len == 0) {
292 w[0] = cm0;
293 w[1] = cm1;
294 w[2] = cm2;
295 w[3] = cm3;
296 br_aes_ct64_interleave_in(&q[0], &q[4], w);
297 br_aes_ct64_ortho(q);
298 br_aes_ct64_bitslice_encrypt(
299 ctx->num_rounds, sk_exp, q);
300 br_aes_ct64_ortho(q);
301 br_aes_ct64_interleave_out(w, q[0], q[4]);
302 cm0 = w[0];
303 cm1 = w[1];
304 cm2 = w[2];
305 cm3 = w[3];
306 break;
307 }
308 }
309
310 br_enc32be(ivbuf + 0, iv0);
311 br_enc32be(ivbuf + 4, iv1);
312 br_enc32be(ivbuf + 8, iv2);
313 br_enc32be(ivbuf + 12, iv3);
314 br_enc32le((unsigned char *)cbcmac + 0, cm0);
315 br_enc32le((unsigned char *)cbcmac + 4, cm1);
316 br_enc32le((unsigned char *)cbcmac + 8, cm2);
317 br_enc32le((unsigned char *)cbcmac + 12, cm3);
318 }
319
320 /* see bearssl_block.h */
321 void
322 br_aes_ct64_ctrcbc_decrypt(const br_aes_ct64_ctrcbc_keys *ctx,
323 void *ctr, void *cbcmac, void *data, size_t len)
324 {
325 unsigned char *buf;
326 unsigned char *ivbuf;
327 uint32_t iv0, iv1, iv2, iv3;
328 uint32_t cm0, cm1, cm2, cm3;
329 uint64_t sk_exp[120];
330 uint64_t q[8];
331
332 br_aes_ct64_skey_expand(sk_exp, ctx->num_rounds, ctx->skey);
333
334 /*
335 * We keep the counter as four 32-bit values, with big-endian
336 * convention, because that's what is expected for purposes of
337 * incrementing the counter value.
338 */
339 ivbuf = ctr;
340 iv0 = br_dec32be(ivbuf + 0);
341 iv1 = br_dec32be(ivbuf + 4);
342 iv2 = br_dec32be(ivbuf + 8);
343 iv3 = br_dec32be(ivbuf + 12);
344
345 /*
346 * The current CBC-MAC value is kept in little-endian convention.
347 */
348 cm0 = br_dec32le((unsigned char *)cbcmac + 0);
349 cm1 = br_dec32le((unsigned char *)cbcmac + 4);
350 cm2 = br_dec32le((unsigned char *)cbcmac + 8);
351 cm3 = br_dec32le((unsigned char *)cbcmac + 12);
352
353 buf = data;
354 memset(q, 0, sizeof q);
355 while (len > 0) {
356 uint32_t w[8], carry;
357 unsigned char tmp[16];
358
359 /*
360 * The bitslice implementation expects values in
361 * little-endian convention, so we have to byteswap them.
362 */
363 w[0] = br_swap32(iv0);
364 w[1] = br_swap32(iv1);
365 w[2] = br_swap32(iv2);
366 w[3] = br_swap32(iv3);
367 iv3 ++;
368 carry = ~(iv3 | -iv3) >> 31;
369 iv2 += carry;
370 carry &= -(~(iv2 | -iv2) >> 31);
371 iv1 += carry;
372 carry &= -(~(iv1 | -iv1) >> 31);
373 iv0 += carry;
374
375 /*
376 * The block for CBC-MAC.
377 */
378 w[4] = cm0 ^ br_dec32le(buf + 0);
379 w[5] = cm1 ^ br_dec32le(buf + 4);
380 w[6] = cm2 ^ br_dec32le(buf + 8);
381 w[7] = cm3 ^ br_dec32le(buf + 12);
382
383 br_aes_ct64_interleave_in(&q[0], &q[4], w);
384 br_aes_ct64_interleave_in(&q[1], &q[5], w + 4);
385 br_aes_ct64_ortho(q);
386 br_aes_ct64_bitslice_encrypt(ctx->num_rounds, sk_exp, q);
387 br_aes_ct64_ortho(q);
388 br_aes_ct64_interleave_out(w, q[0], q[4]);
389 br_aes_ct64_interleave_out(w + 4, q[1], q[5]);
390
391 br_enc32le(tmp + 0, w[0]);
392 br_enc32le(tmp + 4, w[1]);
393 br_enc32le(tmp + 8, w[2]);
394 br_enc32le(tmp + 12, w[3]);
395 xorbuf(buf, tmp, 16);
396 cm0 = w[4];
397 cm1 = w[5];
398 cm2 = w[6];
399 cm3 = w[7];
400 buf += 16;
401 len -= 16;
402 }
403
404 br_enc32be(ivbuf + 0, iv0);
405 br_enc32be(ivbuf + 4, iv1);
406 br_enc32be(ivbuf + 8, iv2);
407 br_enc32be(ivbuf + 12, iv3);
408 br_enc32le((unsigned char *)cbcmac + 0, cm0);
409 br_enc32le((unsigned char *)cbcmac + 4, cm1);
410 br_enc32le((unsigned char *)cbcmac + 8, cm2);
411 br_enc32le((unsigned char *)cbcmac + 12, cm3);
412 }
413
414 /* see bearssl_block.h */
415 const br_block_ctrcbc_class br_aes_ct64_ctrcbc_vtable = {
416 sizeof(br_aes_ct64_ctrcbc_keys),
417 16,
418 4,
419 (void (*)(const br_block_ctrcbc_class **, const void *, size_t))
420 &br_aes_ct64_ctrcbc_init,
421 (void (*)(const br_block_ctrcbc_class *const *,
422 void *, void *, void *, size_t))
423 &br_aes_ct64_ctrcbc_encrypt,
424 (void (*)(const br_block_ctrcbc_class *const *,
425 void *, void *, void *, size_t))
426 &br_aes_ct64_ctrcbc_decrypt,
427 (void (*)(const br_block_ctrcbc_class *const *,
428 void *, void *, size_t))
429 &br_aes_ct64_ctrcbc_ctr,
430 (void (*)(const br_block_ctrcbc_class *const *,
431 void *, const void *, size_t))
432 &br_aes_ct64_ctrcbc_mac
433 };
The BearSSL library and tools.