1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953
|
/* serpent.c - Implementation of the Serpent encryption algorithm.
* Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser general Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <config.h>
#include <string.h>
#include <stdio.h>
#include "types.h"
#include "g10lib.h"
#include "cipher.h"
#include "bithelp.h"
/* Number of rounds per Serpent encrypt/decrypt operation. */
#define ROUNDS 32
/* Magic number, used during generating of the subkeys. */
#define PHI 0x9E3779B9
/* Serpent works on 128 bit blocks. */
typedef u32 serpent_block_t[4];
/* Serpent key, provided by the user. If the original key is shorter
than 256 bits, it is padded. */
typedef u32 serpent_key_t[8];
/* The key schedule consists of 33 128 bit subkeys. */
typedef u32 serpent_subkeys_t[ROUNDS + 1][4];
/* A Serpent context. */
typedef struct serpent_context
{
serpent_subkeys_t keys; /* Generated subkeys. */
} serpent_context_t;
/* A prototype. */
static const char *serpent_test (void);
#define byte_swap_32(x) \
(0 \
| (((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) \
| (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24))
/* These are the S-Boxes of Serpent. They are copied from Serpents
reference implementation (the optimized one, contained in
`floppy2') and are therefore:
Copyright (C) 1998 Ross Anderson, Eli Biham, Lars Knudsen.
To quote the Serpent homepage
(http://www.cl.cam.ac.uk/~rja14/serpent.html):
"Serpent is now completely in the public domain, and we impose no
restrictions on its use. This was announced on the 21st August at
the First AES Candidate Conference. The optimised implementations
in the submission package are now under the GNU PUBLIC LICENSE
(GPL), although some comments in the code still say otherwise. You
are welcome to use Serpent for any application." */
#define SBOX0(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t05, t06, t07, t08, t09; \
u32 t11, t12, t13, t14, t15, t17, t01; \
t01 = b ^ c ; \
t02 = a | d ; \
t03 = a ^ b ; \
z = t02 ^ t01; \
t05 = c | z ; \
t06 = a ^ d ; \
t07 = b | c ; \
t08 = d & t05; \
t09 = t03 & t07; \
y = t09 ^ t08; \
t11 = t09 & y ; \
t12 = c ^ d ; \
t13 = t07 ^ t11; \
t14 = b & t06; \
t15 = t06 ^ t13; \
w = ~ t15; \
t17 = w ^ t14; \
x = t12 ^ t17; \
}
#define SBOX0_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t08, t09, t10; \
u32 t12, t13, t14, t15, t17, t18, t01; \
t01 = c ^ d ; \
t02 = a | b ; \
t03 = b | c ; \
t04 = c & t01; \
t05 = t02 ^ t01; \
t06 = a | t04; \
y = ~ t05; \
t08 = b ^ d ; \
t09 = t03 & t08; \
t10 = d | y ; \
x = t09 ^ t06; \
t12 = a | t05; \
t13 = x ^ t12; \
t14 = t03 ^ t10; \
t15 = a ^ c ; \
z = t14 ^ t13; \
t17 = t05 & t13; \
t18 = t14 | t17; \
w = t15 ^ t18; \
}
#define SBOX1(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t08; \
u32 t10, t11, t12, t13, t16, t17, t01; \
t01 = a | d ; \
t02 = c ^ d ; \
t03 = ~ b ; \
t04 = a ^ c ; \
t05 = a | t03; \
t06 = d & t04; \
t07 = t01 & t02; \
t08 = b | t06; \
y = t02 ^ t05; \
t10 = t07 ^ t08; \
t11 = t01 ^ t10; \
t12 = y ^ t11; \
t13 = b & d ; \
z = ~ t10; \
x = t13 ^ t12; \
t16 = t10 | x ; \
t17 = t05 & t16; \
w = c ^ t17; \
}
#define SBOX1_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t08; \
u32 t09, t10, t11, t14, t15, t17, t01; \
t01 = a ^ b ; \
t02 = b | d ; \
t03 = a & c ; \
t04 = c ^ t02; \
t05 = a | t04; \
t06 = t01 & t05; \
t07 = d | t03; \
t08 = b ^ t06; \
t09 = t07 ^ t06; \
t10 = t04 | t03; \
t11 = d & t08; \
y = ~ t09; \
x = t10 ^ t11; \
t14 = a | y ; \
t15 = t06 ^ x ; \
z = t01 ^ t04; \
t17 = c ^ t15; \
w = t14 ^ t17; \
}
#define SBOX2(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t05, t06, t07, t08; \
u32 t09, t10, t12, t13, t14, t01; \
t01 = a | c ; \
t02 = a ^ b ; \
t03 = d ^ t01; \
w = t02 ^ t03; \
t05 = c ^ w ; \
t06 = b ^ t05; \
t07 = b | t05; \
t08 = t01 & t06; \
t09 = t03 ^ t07; \
t10 = t02 | t09; \
x = t10 ^ t08; \
t12 = a | d ; \
t13 = t09 ^ x ; \
t14 = b ^ t13; \
z = ~ t09; \
y = t12 ^ t14; \
}
#define SBOX2_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t06, t07, t08, t09; \
u32 t10, t11, t12, t15, t16, t17, t01; \
t01 = a ^ d ; \
t02 = c ^ d ; \
t03 = a & c ; \
t04 = b | t02; \
w = t01 ^ t04; \
t06 = a | c ; \
t07 = d | w ; \
t08 = ~ d ; \
t09 = b & t06; \
t10 = t08 | t03; \
t11 = b & t07; \
t12 = t06 & t02; \
z = t09 ^ t10; \
x = t12 ^ t11; \
t15 = c & z ; \
t16 = w ^ x ; \
t17 = t10 ^ t15; \
y = t16 ^ t17; \
}
#define SBOX3(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t08; \
u32 t09, t10, t11, t13, t14, t15, t01; \
t01 = a ^ c ; \
t02 = a | d ; \
t03 = a & d ; \
t04 = t01 & t02; \
t05 = b | t03; \
t06 = a & b ; \
t07 = d ^ t04; \
t08 = c | t06; \
t09 = b ^ t07; \
t10 = d & t05; \
t11 = t02 ^ t10; \
z = t08 ^ t09; \
t13 = d | z ; \
t14 = a | t07; \
t15 = b & t13; \
y = t08 ^ t11; \
w = t14 ^ t15; \
x = t05 ^ t04; \
}
#define SBOX3_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t09; \
u32 t11, t12, t13, t14, t16, t01; \
t01 = c | d ; \
t02 = a | d ; \
t03 = c ^ t02; \
t04 = b ^ t02; \
t05 = a ^ d ; \
t06 = t04 & t03; \
t07 = b & t01; \
y = t05 ^ t06; \
t09 = a ^ t03; \
w = t07 ^ t03; \
t11 = w | t05; \
t12 = t09 & t11; \
t13 = a & y ; \
t14 = t01 ^ t05; \
x = b ^ t12; \
t16 = b | t13; \
z = t14 ^ t16; \
}
#define SBOX4(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t08, t09; \
u32 t10, t11, t12, t13, t14, t15, t16, t01; \
t01 = a | b ; \
t02 = b | c ; \
t03 = a ^ t02; \
t04 = b ^ d ; \
t05 = d | t03; \
t06 = d & t01; \
z = t03 ^ t06; \
t08 = z & t04; \
t09 = t04 & t05; \
t10 = c ^ t06; \
t11 = b & c ; \
t12 = t04 ^ t08; \
t13 = t11 | t03; \
t14 = t10 ^ t09; \
t15 = a & t05; \
t16 = t11 | t12; \
y = t13 ^ t08; \
x = t15 ^ t16; \
w = ~ t14; \
}
#define SBOX4_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t09; \
u32 t10, t11, t12, t13, t15, t01; \
t01 = b | d ; \
t02 = c | d ; \
t03 = a & t01; \
t04 = b ^ t02; \
t05 = c ^ d ; \
t06 = ~ t03; \
t07 = a & t04; \
x = t05 ^ t07; \
t09 = x | t06; \
t10 = a ^ t07; \
t11 = t01 ^ t09; \
t12 = d ^ t04; \
t13 = c | t10; \
z = t03 ^ t12; \
t15 = a ^ t04; \
y = t11 ^ t13; \
w = t15 ^ t09; \
}
#define SBOX5(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t07, t08, t09; \
u32 t10, t11, t12, t13, t14, t01; \
t01 = b ^ d ; \
t02 = b | d ; \
t03 = a & t01; \
t04 = c ^ t02; \
t05 = t03 ^ t04; \
w = ~ t05; \
t07 = a ^ t01; \
t08 = d | w ; \
t09 = b | t05; \
t10 = d ^ t08; \
t11 = b | t07; \
t12 = t03 | w ; \
t13 = t07 | t10; \
t14 = t01 ^ t11; \
y = t09 ^ t13; \
x = t07 ^ t08; \
z = t12 ^ t14; \
}
#define SBOX5_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t07, t08, t09; \
u32 t10, t12, t13, t15, t16, t01; \
t01 = a & d ; \
t02 = c ^ t01; \
t03 = a ^ d ; \
t04 = b & t02; \
t05 = a & c ; \
w = t03 ^ t04; \
t07 = a & w ; \
t08 = t01 ^ w ; \
t09 = b | t05; \
t10 = ~ b ; \
x = t08 ^ t09; \
t12 = t10 | t07; \
t13 = w | x ; \
z = t02 ^ t12; \
t15 = t02 ^ t13; \
t16 = b ^ d ; \
y = t16 ^ t15; \
}
#define SBOX6(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t07, t08, t09, t10; \
u32 t11, t12, t13, t15, t17, t18, t01; \
t01 = a & d ; \
t02 = b ^ c ; \
t03 = a ^ d ; \
t04 = t01 ^ t02; \
t05 = b | c ; \
x = ~ t04; \
t07 = t03 & t05; \
t08 = b & x ; \
t09 = a | c ; \
t10 = t07 ^ t08; \
t11 = b | d ; \
t12 = c ^ t11; \
t13 = t09 ^ t10; \
y = ~ t13; \
t15 = x & t03; \
z = t12 ^ t07; \
t17 = a ^ b ; \
t18 = y ^ t15; \
w = t17 ^ t18; \
}
#define SBOX6_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t07, t08, t09; \
u32 t12, t13, t14, t15, t16, t17, t01; \
t01 = a ^ c ; \
t02 = ~ c ; \
t03 = b & t01; \
t04 = b | t02; \
t05 = d | t03; \
t06 = b ^ d ; \
t07 = a & t04; \
t08 = a | t02; \
t09 = t07 ^ t05; \
x = t06 ^ t08; \
w = ~ t09; \
t12 = b & w ; \
t13 = t01 & t05; \
t14 = t01 ^ t12; \
t15 = t07 ^ t13; \
t16 = d | t02; \
t17 = a ^ x ; \
z = t17 ^ t15; \
y = t16 ^ t14; \
}
#define SBOX7(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t05, t06, t08, t09, t10; \
u32 t11, t13, t14, t15, t16, t17, t01; \
t01 = a & c ; \
t02 = ~ d ; \
t03 = a & t02; \
t04 = b | t01; \
t05 = a & b ; \
t06 = c ^ t04; \
z = t03 ^ t06; \
t08 = c | z ; \
t09 = d | t05; \
t10 = a ^ t08; \
t11 = t04 & z ; \
x = t09 ^ t10; \
t13 = b ^ x ; \
t14 = t01 ^ x ; \
t15 = c ^ t05; \
t16 = t11 | t13; \
t17 = t02 | t14; \
w = t15 ^ t17; \
y = a ^ t16; \
}
#define SBOX7_INVERSE(a, b, c, d, w, x, y, z) \
{ \
u32 t02, t03, t04, t06, t07, t08, t09; \
u32 t10, t11, t13, t14, t15, t16, t01; \
t01 = a & b ; \
t02 = a | b ; \
t03 = c | t01; \
t04 = d & t02; \
z = t03 ^ t04; \
t06 = b ^ t04; \
t07 = d ^ z ; \
t08 = ~ t07; \
t09 = t06 | t08; \
t10 = b ^ d ; \
t11 = a | d ; \
x = a ^ t09; \
t13 = c ^ t06; \
t14 = c & t11; \
t15 = d | x ; \
t16 = t01 | t10; \
w = t13 ^ t15; \
y = t14 ^ t16; \
}
/* XOR BLOCK1 into BLOCK0. */
#define BLOCK_XOR(block0, block1) \
{ \
block0[0] ^= block1[0]; \
block0[1] ^= block1[1]; \
block0[2] ^= block1[2]; \
block0[3] ^= block1[3]; \
}
/* Copy BLOCK_SRC to BLOCK_DST. */
#define BLOCK_COPY(block_dst, block_src) \
{ \
block_dst[0] = block_src[0]; \
block_dst[1] = block_src[1]; \
block_dst[2] = block_src[2]; \
block_dst[3] = block_src[3]; \
}
/* Apply SBOX number WHICH to to the block found in ARRAY0 at index
INDEX, writing the output to the block found in ARRAY1 at index
INDEX. */
#define SBOX(which, array0, array1, index) \
SBOX##which (array0[index + 0], array0[index + 1], \
array0[index + 2], array0[index + 3], \
array1[index + 0], array1[index + 1], \
array1[index + 2], array1[index + 3]);
/* Apply inverse SBOX number WHICH to to the block found in ARRAY0 at
index INDEX, writing the output to the block found in ARRAY1 at
index INDEX. */
#define SBOX_INVERSE(which, array0, array1, index) \
SBOX##which##_INVERSE (array0[index + 0], array0[index + 1], \
array0[index + 2], array0[index + 3], \
array1[index + 0], array1[index + 1], \
array1[index + 2], array1[index + 3]);
/* Apply the linear transformation to BLOCK. */
#define LINEAR_TRANSFORMATION(block) \
{ \
block[0] = rol (block[0], 13); \
block[2] = rol (block[2], 3); \
block[1] = block[1] ^ block[0] ^ block[2]; \
block[3] = block[3] ^ block[2] ^ (block[0] << 3); \
block[1] = rol (block[1], 1); \
block[3] = rol (block[3], 7); \
block[0] = block[0] ^ block[1] ^ block[3]; \
block[2] = block[2] ^ block[3] ^ (block[1] << 7); \
block[0] = rol (block[0], 5); \
block[2] = rol (block[2], 22); \
}
/* Apply the inverse linear transformation to BLOCK. */
#define LINEAR_TRANSFORMATION_INVERSE(block) \
{ \
block[2] = ror (block[2], 22); \
block[0] = ror (block[0] , 5); \
block[2] = block[2] ^ block[3] ^ (block[1] << 7); \
block[0] = block[0] ^ block[1] ^ block[3]; \
block[3] = ror (block[3], 7); \
block[1] = ror (block[1], 1); \
block[3] = block[3] ^ block[2] ^ (block[0] << 3); \
block[1] = block[1] ^ block[0] ^ block[2]; \
block[2] = ror (block[2], 3); \
block[0] = ror (block[0], 13); \
}
/* Apply a Serpent round to BLOCK, using the SBOX number WHICH and the
subkeys contained in SUBKEYS. Use BLOCK_TMP as temporary storage.
This macro increments `round'. */
#define ROUND(which, subkeys, block, block_tmp) \
{ \
BLOCK_XOR (block, subkeys[round]); \
round++; \
SBOX (which, block, block_tmp, 0); \
LINEAR_TRANSFORMATION (block_tmp); \
BLOCK_COPY (block, block_tmp); \
}
/* Apply the last Serpent round to BLOCK, using the SBOX number WHICH
and the subkeys contained in SUBKEYS. Use BLOCK_TMP as temporary
storage. The result will be stored in BLOCK_TMP. This macro
increments `round'. */
#define ROUND_LAST(which, subkeys, block, block_tmp) \
{ \
BLOCK_XOR (block, subkeys[round]); \
round++; \
SBOX (which, block, block_tmp, 0); \
BLOCK_XOR (block_tmp, subkeys[round]); \
round++; \
}
/* Apply an inverse Serpent round to BLOCK, using the SBOX number
WHICH and the subkeys contained in SUBKEYS. Use BLOCK_TMP as
temporary storage. This macro increments `round'. */
#define ROUND_INVERSE(which, subkey, block, block_tmp) \
{ \
LINEAR_TRANSFORMATION_INVERSE (block); \
SBOX_INVERSE (which, block, block_tmp, 0); \
BLOCK_XOR (block_tmp, subkey[round]); \
round--; \
BLOCK_COPY (block, block_tmp); \
}
/* Apply the first Serpent round to BLOCK, using the SBOX number WHICH
and the subkeys contained in SUBKEYS. Use BLOCK_TMP as temporary
storage. The result will be stored in BLOCK_TMP. This macro
increments `round'. */
#define ROUND_FIRST_INVERSE(which, subkeys, block, block_tmp) \
{ \
BLOCK_XOR (block, subkeys[round]); \
round--; \
SBOX_INVERSE (which, block, block_tmp, 0); \
BLOCK_XOR (block_tmp, subkeys[round]); \
round--; \
}
/* Convert the user provided key KEY of KEY_LENGTH bytes into the
internally used format. */
static void
serpent_key_prepare (const byte *key, unsigned int key_length,
serpent_key_t key_prepared)
{
int i;
/* Copy key. */
memcpy (key_prepared, key, key_length);
key_length /= 4;
#ifdef WORDS_BIGENDIAN
for (i = 0; i < key_length; i++)
key_prepared[i] = byte_swap_32 (key_prepared[i]);
#else
i = key_length;
#endif
if (i < 8)
{
/* Key must be padded according to the Serpent
specification. */
key_prepared[i] = 0x00000001;
for (i++; i < 8; i++)
key_prepared[i] = 0;
}
}
/* Derive the 33 subkeys from KEY and store them in SUBKEYS. */
static void
serpent_subkeys_generate (serpent_key_t key, serpent_subkeys_t subkeys)
{
u32 w_real[140]; /* The `prekey'. */
u32 k[132];
u32 *w = &w_real[8];
int i, j;
/* Initialize with key values. */
for (i = 0; i < 8; i++)
w[i - 8] = key[i];
/* Expand to intermediate key using the affine recurrence. */
for (i = 0; i < 132; i++)
w[i] = rol (w[i - 8] ^ w[i - 5] ^ w[i - 3] ^ w[i - 1] ^ PHI ^ i, 11);
/* Calculate subkeys via S-Boxes, in bitslice mode. */
SBOX (3, w, k, 0);
SBOX (2, w, k, 4);
SBOX (1, w, k, 8);
SBOX (0, w, k, 12);
SBOX (7, w, k, 16);
SBOX (6, w, k, 20);
SBOX (5, w, k, 24);
SBOX (4, w, k, 28);
SBOX (3, w, k, 32);
SBOX (2, w, k, 36);
SBOX (1, w, k, 40);
SBOX (0, w, k, 44);
SBOX (7, w, k, 48);
SBOX (6, w, k, 52);
SBOX (5, w, k, 56);
SBOX (4, w, k, 60);
SBOX (3, w, k, 64);
SBOX (2, w, k, 68);
SBOX (1, w, k, 72);
SBOX (0, w, k, 76);
SBOX (7, w, k, 80);
SBOX (6, w, k, 84);
SBOX (5, w, k, 88);
SBOX (4, w, k, 92);
SBOX (3, w, k, 96);
SBOX (2, w, k, 100);
SBOX (1, w, k, 104);
SBOX (0, w, k, 108);
SBOX (7, w, k, 112);
SBOX (6, w, k, 116);
SBOX (5, w, k, 120);
SBOX (4, w, k, 124);
SBOX (3, w, k, 128);
/* Renumber subkeys. */
for (i = 0; i < ROUNDS + 1; i++)
for (j = 0; j < 4; j++)
subkeys[i][j] = k[4 * i + j];
}
/* Initialize CONTEXT with the key KEY of KEY_LENGTH bits. */
static void
serpent_setkey_internal (serpent_context_t *context,
const byte *key, unsigned int key_length)
{
serpent_key_t key_prepared;
serpent_key_prepare (key, key_length, key_prepared);
serpent_subkeys_generate (key_prepared, context->keys);
_gcry_burn_stack (272 * sizeof (u32));
}
/* Initialize CTX with the key KEY of KEY_LENGTH bytes. */
static gcry_err_code_t
serpent_setkey (void *ctx,
const byte *key, unsigned int key_length)
{
serpent_context_t *context = ctx;
static const char *serpent_test_ret;
static int serpent_init_done;
gcry_err_code_t ret = GPG_ERR_NO_ERROR;
if (! serpent_init_done)
{
/* Execute a self-test the first time, Serpent is used. */
serpent_test_ret = serpent_test ();
if (serpent_test_ret)
log_error ("Serpent test failure: %s\n", serpent_test_ret);
serpent_init_done = 1;
}
if (serpent_test_ret)
ret = GPG_ERR_SELFTEST_FAILED;
else
{
serpent_setkey_internal (context, key, key_length);
_gcry_burn_stack (sizeof (serpent_key_t));
}
return ret;
}
static void
serpent_encrypt_internal (serpent_context_t *context,
const byte *input, byte *output)
{
serpent_block_t b, b_next;
int round = 0;
memcpy (b, input, sizeof (b));
#ifdef WORDS_BIGENDIAN
b[0] = byte_swap_32 (b[0]);
b[1] = byte_swap_32 (b[1]);
b[2] = byte_swap_32 (b[2]);
b[3] = byte_swap_32 (b[3]);
#endif
ROUND (0, context->keys, b, b_next);
ROUND (1, context->keys, b, b_next);
ROUND (2, context->keys, b, b_next);
ROUND (3, context->keys, b, b_next);
ROUND (4, context->keys, b, b_next);
ROUND (5, context->keys, b, b_next);
ROUND (6, context->keys, b, b_next);
ROUND (7, context->keys, b, b_next);
ROUND (0, context->keys, b, b_next);
ROUND (1, context->keys, b, b_next);
ROUND (2, context->keys, b, b_next);
ROUND (3, context->keys, b, b_next);
ROUND (4, context->keys, b, b_next);
ROUND (5, context->keys, b, b_next);
ROUND (6, context->keys, b, b_next);
ROUND (7, context->keys, b, b_next);
ROUND (0, context->keys, b, b_next);
ROUND (1, context->keys, b, b_next);
ROUND (2, context->keys, b, b_next);
ROUND (3, context->keys, b, b_next);
ROUND (4, context->keys, b, b_next);
ROUND (5, context->keys, b, b_next);
ROUND (6, context->keys, b, b_next);
ROUND (7, context->keys, b, b_next);
ROUND (0, context->keys, b, b_next);
ROUND (1, context->keys, b, b_next);
ROUND (2, context->keys, b, b_next);
ROUND (3, context->keys, b, b_next);
ROUND (4, context->keys, b, b_next);
ROUND (5, context->keys, b, b_next);
ROUND (6, context->keys, b, b_next);
ROUND_LAST (7, context->keys, b, b_next);
#ifdef WORDS_BIGENDIAN
b_next[0] = byte_swap_32 (b_next[0]);
b_next[1] = byte_swap_32 (b_next[1]);
b_next[2] = byte_swap_32 (b_next[2]);
b_next[3] = byte_swap_32 (b_next[3]);
#endif
memcpy (output, b_next, sizeof (b_next));
}
static void
serpent_decrypt_internal (serpent_context_t *context,
const byte *input, byte *output)
{
serpent_block_t b, b_next;
int round = ROUNDS;
memcpy (b_next, input, sizeof (b));
#ifdef WORDS_BIGENDIAN
b_next[0] = byte_swap_32 (b_next[0]);
b_next[1] = byte_swap_32 (b_next[1]);
b_next[2] = byte_swap_32 (b_next[2]);
b_next[3] = byte_swap_32 (b_next[3]);
#endif
ROUND_FIRST_INVERSE (7, context->keys, b_next, b);
ROUND_INVERSE (6, context->keys, b, b_next);
ROUND_INVERSE (5, context->keys, b, b_next);
ROUND_INVERSE (4, context->keys, b, b_next);
ROUND_INVERSE (3, context->keys, b, b_next);
ROUND_INVERSE (2, context->keys, b, b_next);
ROUND_INVERSE (1, context->keys, b, b_next);
ROUND_INVERSE (0, context->keys, b, b_next);
ROUND_INVERSE (7, context->keys, b, b_next);
ROUND_INVERSE (6, context->keys, b, b_next);
ROUND_INVERSE (5, context->keys, b, b_next);
ROUND_INVERSE (4, context->keys, b, b_next);
ROUND_INVERSE (3, context->keys, b, b_next);
ROUND_INVERSE (2, context->keys, b, b_next);
ROUND_INVERSE (1, context->keys, b, b_next);
ROUND_INVERSE (0, context->keys, b, b_next);
ROUND_INVERSE (7, context->keys, b, b_next);
ROUND_INVERSE (6, context->keys, b, b_next);
ROUND_INVERSE (5, context->keys, b, b_next);
ROUND_INVERSE (4, context->keys, b, b_next);
ROUND_INVERSE (3, context->keys, b, b_next);
ROUND_INVERSE (2, context->keys, b, b_next);
ROUND_INVERSE (1, context->keys, b, b_next);
ROUND_INVERSE (0, context->keys, b, b_next);
ROUND_INVERSE (7, context->keys, b, b_next);
ROUND_INVERSE (6, context->keys, b, b_next);
ROUND_INVERSE (5, context->keys, b, b_next);
ROUND_INVERSE (4, context->keys, b, b_next);
ROUND_INVERSE (3, context->keys, b, b_next);
ROUND_INVERSE (2, context->keys, b, b_next);
ROUND_INVERSE (1, context->keys, b, b_next);
ROUND_INVERSE (0, context->keys, b, b_next);
#ifdef WORDS_BIGENDIAN
b_next[0] = byte_swap_32 (b_next[0]);
b_next[1] = byte_swap_32 (b_next[1]);
b_next[2] = byte_swap_32 (b_next[2]);
b_next[3] = byte_swap_32 (b_next[3]);
#endif
memcpy (output, b_next, sizeof (b_next));
}
static void
serpent_encrypt (void *ctx, byte *buffer_out, const byte *buffer_in)
{
serpent_context_t *context = ctx;
serpent_encrypt_internal (context, buffer_in, buffer_out);
_gcry_burn_stack (2 * sizeof (serpent_block_t));
}
static void
serpent_decrypt (void *ctx, byte *buffer_out, const byte *buffer_in)
{
serpent_context_t *context = ctx;
serpent_decrypt_internal (context, buffer_in, buffer_out);
_gcry_burn_stack (2 * sizeof (serpent_block_t));
}
/* Serpent test. */
static const char *
serpent_test (void)
{
serpent_context_t context;
unsigned char scratch[16];
unsigned int i;
static struct test
{
int key_length;
unsigned char key[32];
unsigned char text_plain[16];
unsigned char text_cipher[16];
} test_data[] =
{
{
16,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
"\xD2\x9D\x57\x6F\xCE\xA3\xA3\xA7\xED\x90\x99\xF2\x92\x73\xD7\x8E",
"\xB2\x28\x8B\x96\x8A\xE8\xB0\x86\x48\xD1\xCE\x96\x06\xFD\x99\x2D"
},
{
24,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00",
"\xD2\x9D\x57\x6F\xCE\xAB\xA3\xA7\xED\x98\x99\xF2\x92\x7B\xD7\x8E",
"\x13\x0E\x35\x3E\x10\x37\xC2\x24\x05\xE8\xFA\xEF\xB2\xC3\xC3\xE9"
},
{
32,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
"\xD0\x95\x57\x6F\xCE\xA3\xE3\xA7\xED\x98\xD9\xF2\x90\x73\xD7\x8E",
"\xB9\x0E\xE5\x86\x2D\xE6\x91\x68\xF2\xBD\xD5\x12\x5B\x45\x47\x2B"
},
{
32,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
"\x00\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x03\x00\x00\x00",
"\x20\x61\xA4\x27\x82\xBD\x52\xEC\x69\x1E\xC3\x83\xB0\x3B\xA7\x7C"
},
{
0
},
};
for (i = 0; test_data[i].key_length; i++)
{
serpent_setkey_internal (&context, test_data[i].key,
test_data[i].key_length);
serpent_encrypt_internal (&context, test_data[i].text_plain, scratch);
if (memcmp (scratch, test_data[i].text_cipher, sizeof (serpent_block_t)))
switch (test_data[i].key_length)
{
case 16:
return "Serpent-128 test encryption failed.";
case 24:
return "Serpent-192 test encryption failed.";
case 32:
return "Serpent-256 test encryption failed.";
}
serpent_decrypt_internal (&context, test_data[i].text_cipher, scratch);
if (memcmp (scratch, test_data[i].text_plain, sizeof (serpent_block_t)))
switch (test_data[i].key_length)
{
case 16:
return "Serpent-128 test decryption failed.";
case 24:
return "Serpent-192 test decryption failed.";
case 32:
return "Serpent-256 test decryption failed.";
}
}
return NULL;
}
/* "SERPENT" is an alias for "SERPENT128". */
static const char *cipher_spec_serpent128_aliases[] =
{
"SERPENT",
NULL
};
gcry_cipher_spec_t _gcry_cipher_spec_serpent128 =
{
"SERPENT128", cipher_spec_serpent128_aliases, NULL, 16, 128,
sizeof (serpent_context_t),
serpent_setkey, serpent_encrypt, serpent_decrypt
};
gcry_cipher_spec_t _gcry_cipher_spec_serpent192 =
{
"SERPENT192", NULL, NULL, 16, 192,
sizeof (serpent_context_t),
serpent_setkey, serpent_encrypt, serpent_decrypt
};
gcry_cipher_spec_t _gcry_cipher_spec_serpent256 =
{
"SERPENT256", NULL, NULL, 16, 256,
sizeof (serpent_context_t),
serpent_setkey, serpent_encrypt, serpent_decrypt
};
|