1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10
11 /**
12 @file twofish.c
13 Implementation of Twofish by Tom St Denis
14 */
15 #include "tomcrypt_private.h"
16
17 #ifdef LTC_TWOFISH
18
19 /* first LTC_TWOFISH_ALL_TABLES must ensure LTC_TWOFISH_TABLES is defined */
20 #ifdef LTC_TWOFISH_ALL_TABLES
21 #ifndef LTC_TWOFISH_TABLES
22 #define LTC_TWOFISH_TABLES
23 #endif
24 #endif
25
26 const struct ltc_cipher_descriptor twofish_desc =
27 {
28 "twofish",
29 7,
30 16, 32, 16, 16,
31 &twofish_setup,
32 &twofish_ecb_encrypt,
33 &twofish_ecb_decrypt,
34 &twofish_test,
35 &twofish_done,
36 &twofish_keysize,
37 NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
38 };
39
40 /* the two polynomials */
41 #ifndef LTC_TWOFISH_TABLES
42 #define MDS_POLY 0x169
43 #endif
44 #ifndef LTC_TWOFISH_ALL_TABLES
45 #define RS_POLY 0x14D
46 #endif
47
48 /* The 4x8 RS Linear Transform */
49 static const unsigned char RS[4][8] = {
50 { 0x01, 0xA4, 0x55, 0x87, 0x5A, 0x58, 0xDB, 0x9E },
51 { 0xA4, 0x56, 0x82, 0xF3, 0X1E, 0XC6, 0X68, 0XE5 },
52 { 0X02, 0XA1, 0XFC, 0XC1, 0X47, 0XAE, 0X3D, 0X19 },
53 { 0XA4, 0X55, 0X87, 0X5A, 0X58, 0XDB, 0X9E, 0X03 }
54 };
55
56 #ifdef LTC_TWOFISH_SMALL
57 /* sbox usage orderings */
58 static const unsigned char qord[4][5] = {
59 { 1, 1, 0, 0, 1 },
60 { 0, 1, 1, 0, 0 },
61 { 0, 0, 0, 1, 1 },
62 { 1, 0, 1, 1, 0 }
63 };
64 #endif /* LTC_TWOFISH_SMALL */
65
66 #ifdef LTC_TWOFISH_TABLES
67
68 #define __LTC_TWOFISH_TAB_C__
69 #include "twofish_tab.c"
70
71 #define sbox(i, x) ((ulong32)SBOX[i][(x)&255])
72
73 #else
74
75 /* The Q-box tables */
76 static const unsigned char qbox[2][4][16] = {
77 {
78 { 0x8, 0x1, 0x7, 0xD, 0x6, 0xF, 0x3, 0x2, 0x0, 0xB, 0x5, 0x9, 0xE, 0xC, 0xA, 0x4 },
79 { 0xE, 0XC, 0XB, 0X8, 0X1, 0X2, 0X3, 0X5, 0XF, 0X4, 0XA, 0X6, 0X7, 0X0, 0X9, 0XD },
80 { 0XB, 0XA, 0X5, 0XE, 0X6, 0XD, 0X9, 0X0, 0XC, 0X8, 0XF, 0X3, 0X2, 0X4, 0X7, 0X1 },
81 { 0XD, 0X7, 0XF, 0X4, 0X1, 0X2, 0X6, 0XE, 0X9, 0XB, 0X3, 0X0, 0X8, 0X5, 0XC, 0XA }
82 },
83 {
84 { 0X2, 0X8, 0XB, 0XD, 0XF, 0X7, 0X6, 0XE, 0X3, 0X1, 0X9, 0X4, 0X0, 0XA, 0XC, 0X5 },
85 { 0X1, 0XE, 0X2, 0XB, 0X4, 0XC, 0X3, 0X7, 0X6, 0XD, 0XA, 0X5, 0XF, 0X9, 0X0, 0X8 },
86 { 0X4, 0XC, 0X7, 0X5, 0X1, 0X6, 0X9, 0XA, 0X0, 0XE, 0XD, 0X8, 0X2, 0XB, 0X3, 0XF },
87 { 0xB, 0X9, 0X5, 0X1, 0XC, 0X3, 0XD, 0XE, 0X6, 0X4, 0X7, 0XF, 0X2, 0X0, 0X8, 0XA }
88 }
89 };
90
91 /* computes S_i[x] */
92 #ifdef LTC_CLEAN_STACK
_sbox(int i,ulong32 x)93 static ulong32 _sbox(int i, ulong32 x)
94 #else
95 static ulong32 sbox(int i, ulong32 x)
96 #endif
97 {
98 unsigned char a0,b0,a1,b1,a2,b2,a3,b3,a4,b4,y;
99
100 /* a0,b0 = [x/16], x mod 16 */
101 a0 = (unsigned char)((x>>4)&15);
102 b0 = (unsigned char)((x)&15);
103
104 /* a1 = a0 ^ b0 */
105 a1 = a0 ^ b0;
106
107 /* b1 = a0 ^ ROR(b0, 1) ^ 8a0 */
108 b1 = (a0 ^ ((b0<<3)|(b0>>1)) ^ (a0<<3)) & 15;
109
110 /* a2,b2 = t0[a1], t1[b1] */
111 a2 = qbox[i][0][(int)a1];
112 b2 = qbox[i][1][(int)b1];
113
114 /* a3 = a2 ^ b2 */
115 a3 = a2 ^ b2;
116
117 /* b3 = a2 ^ ROR(b2, 1) ^ 8a2 */
118 b3 = (a2 ^ ((b2<<3)|(b2>>1)) ^ (a2<<3)) & 15;
119
120 /* a4,b4 = t2[a3], t3[b3] */
121 a4 = qbox[i][2][(int)a3];
122 b4 = qbox[i][3][(int)b3];
123
124 /* y = 16b4 + a4 */
125 y = (b4 << 4) + a4;
126
127 /* return result */
128 return (ulong32)y;
129 }
130
131 #ifdef LTC_CLEAN_STACK
sbox(int i,ulong32 x)132 static ulong32 sbox(int i, ulong32 x)
133 {
134 ulong32 y;
135 y = _sbox(i, x);
136 burn_stack(sizeof(unsigned char) * 11);
137 return y;
138 }
139 #endif /* LTC_CLEAN_STACK */
140
141 #endif /* LTC_TWOFISH_TABLES */
142
143 /* computes ab mod p */
gf_mult(ulong32 a,ulong32 b,ulong32 p)144 static ulong32 gf_mult(ulong32 a, ulong32 b, ulong32 p)
145 {
146 ulong32 result, B[2], P[2];
147
148 P[1] = p;
149 B[1] = b;
150 result = P[0] = B[0] = 0;
151
152 /* unrolled branchless GF multiplier */
153 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
154 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
155 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
156 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
157 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
158 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
159 result ^= B[a&1]; a >>= 1; B[1] = P[B[1]>>7] ^ (B[1] << 1);
160 result ^= B[a&1];
161
162 return result;
163 }
164
165 /* computes [y0 y1 y2 y3] = MDS . [x0] */
166 #ifndef LTC_TWOFISH_TABLES
mds_column_mult(unsigned char in,int col)167 static ulong32 mds_column_mult(unsigned char in, int col)
168 {
169 ulong32 x01, x5B, xEF;
170
171 x01 = in;
172 x5B = gf_mult(in, 0x5B, MDS_POLY);
173 xEF = gf_mult(in, 0xEF, MDS_POLY);
174
175 switch (col) {
176 case 0:
177 return (x01 << 0 ) |
178 (x5B << 8 ) |
179 (xEF << 16) |
180 (xEF << 24);
181 case 1:
182 return (xEF << 0 ) |
183 (xEF << 8 ) |
184 (x5B << 16) |
185 (x01 << 24);
186 case 2:
187 return (x5B << 0 ) |
188 (xEF << 8 ) |
189 (x01 << 16) |
190 (xEF << 24);
191 case 3:
192 return (x5B << 0 ) |
193 (x01 << 8 ) |
194 (xEF << 16) |
195 (x5B << 24);
196 }
197 /* avoid warnings, we'd never get here normally but just to calm compiler warnings... */
198 return 0;
199 }
200
201 #else /* !LTC_TWOFISH_TABLES */
202
203 #define mds_column_mult(x, i) mds_tab[i][x]
204
205 #endif /* LTC_TWOFISH_TABLES */
206
207 /* Computes [y0 y1 y2 y3] = MDS . [x0 x1 x2 x3] */
mds_mult(const unsigned char * in,unsigned char * out)208 static void mds_mult(const unsigned char *in, unsigned char *out)
209 {
210 int x;
211 ulong32 tmp;
212 for (tmp = x = 0; x < 4; x++) {
213 tmp ^= mds_column_mult(in[x], x);
214 }
215 STORE32L(tmp, out);
216 }
217
218 #ifdef LTC_TWOFISH_ALL_TABLES
219 /* computes [y0 y1 y2 y3] = RS . [x0 x1 x2 x3 x4 x5 x6 x7] */
rs_mult(const unsigned char * in,unsigned char * out)220 static void rs_mult(const unsigned char *in, unsigned char *out)
221 {
222 ulong32 tmp;
223 tmp = rs_tab0[in[0]] ^ rs_tab1[in[1]] ^ rs_tab2[in[2]] ^ rs_tab3[in[3]] ^
224 rs_tab4[in[4]] ^ rs_tab5[in[5]] ^ rs_tab6[in[6]] ^ rs_tab7[in[7]];
225 STORE32L(tmp, out);
226 }
227
228 #else /* !LTC_TWOFISH_ALL_TABLES */
229
230 /* computes [y0 y1 y2 y3] = RS . [x0 x1 x2 x3 x4 x5 x6 x7] */
rs_mult(const unsigned char * in,unsigned char * out)231 static void rs_mult(const unsigned char *in, unsigned char *out)
232 {
233 int x, y;
234 for (x = 0; x < 4; x++) {
235 out[x] = 0;
236 for (y = 0; y < 8; y++) {
237 out[x] ^= gf_mult(in[y], RS[x][y], RS_POLY);
238 }
239 }
240 }
241
242 #endif
243
244 /* computes h(x) */
h_func(const unsigned char * in,unsigned char * out,const unsigned char * M,int k,int offset)245 static void h_func(const unsigned char *in, unsigned char *out, const unsigned char *M, int k, int offset)
246 {
247 int x;
248 unsigned char y[4];
249 for (x = 0; x < 4; x++) {
250 y[x] = in[x];
251 }
252 switch (k) {
253 case 4:
254 y[0] = (unsigned char)(sbox(1, (ulong32)y[0]) ^ M[4 * (6 + offset) + 0]);
255 y[1] = (unsigned char)(sbox(0, (ulong32)y[1]) ^ M[4 * (6 + offset) + 1]);
256 y[2] = (unsigned char)(sbox(0, (ulong32)y[2]) ^ M[4 * (6 + offset) + 2]);
257 y[3] = (unsigned char)(sbox(1, (ulong32)y[3]) ^ M[4 * (6 + offset) + 3]);
258 /* FALLTHROUGH */
259 case 3:
260 y[0] = (unsigned char)(sbox(1, (ulong32)y[0]) ^ M[4 * (4 + offset) + 0]);
261 y[1] = (unsigned char)(sbox(1, (ulong32)y[1]) ^ M[4 * (4 + offset) + 1]);
262 y[2] = (unsigned char)(sbox(0, (ulong32)y[2]) ^ M[4 * (4 + offset) + 2]);
263 y[3] = (unsigned char)(sbox(0, (ulong32)y[3]) ^ M[4 * (4 + offset) + 3]);
264 /* FALLTHROUGH */
265 case 2:
266 y[0] = (unsigned char)(sbox(1, sbox(0, sbox(0, (ulong32)y[0]) ^ M[4 * (2 + offset) + 0]) ^ M[4 * (0 + offset) + 0]));
267 y[1] = (unsigned char)(sbox(0, sbox(0, sbox(1, (ulong32)y[1]) ^ M[4 * (2 + offset) + 1]) ^ M[4 * (0 + offset) + 1]));
268 y[2] = (unsigned char)(sbox(1, sbox(1, sbox(0, (ulong32)y[2]) ^ M[4 * (2 + offset) + 2]) ^ M[4 * (0 + offset) + 2]));
269 y[3] = (unsigned char)(sbox(0, sbox(1, sbox(1, (ulong32)y[3]) ^ M[4 * (2 + offset) + 3]) ^ M[4 * (0 + offset) + 3]));
270 /* FALLTHROUGH */
271 }
272 mds_mult(y, out);
273 }
274
275 #ifndef LTC_TWOFISH_SMALL
276
277 /* for GCC we don't use pointer aliases */
278 #if defined(__GNUC__)
279 #define S1 skey->twofish.S[0]
280 #define S2 skey->twofish.S[1]
281 #define S3 skey->twofish.S[2]
282 #define S4 skey->twofish.S[3]
283 #endif
284
285 /* the G function */
286 #define g_func(x, dum) (S1[LTC_BYTE(x,0)] ^ S2[LTC_BYTE(x,1)] ^ S3[LTC_BYTE(x,2)] ^ S4[LTC_BYTE(x,3)])
287 #define g1_func(x, dum) (S2[LTC_BYTE(x,0)] ^ S3[LTC_BYTE(x,1)] ^ S4[LTC_BYTE(x,2)] ^ S1[LTC_BYTE(x,3)])
288
289 #else
290
291 #ifdef LTC_CLEAN_STACK
_g_func(ulong32 x,const symmetric_key * key)292 static ulong32 _g_func(ulong32 x, const symmetric_key *key)
293 #else
294 static ulong32 g_func(ulong32 x, const symmetric_key *key)
295 #endif
296 {
297 unsigned char g, i, y, z;
298 ulong32 res;
299
300 res = 0;
301 for (y = 0; y < 4; y++) {
302 z = key->twofish.start;
303
304 /* do unkeyed substitution */
305 g = sbox(qord[y][z++], (x >> (8*y)) & 255);
306
307 /* first subkey */
308 i = 0;
309
310 /* do key mixing+sbox until z==5 */
311 while (z != 5) {
312 g = g ^ key->twofish.S[4*i++ + y];
313 g = sbox(qord[y][z++], g);
314 }
315
316 /* multiply g by a column of the MDS */
317 res ^= mds_column_mult(g, y);
318 }
319 return res;
320 }
321
322 #define g1_func(x, key) g_func(ROLc(x, 8), key)
323
324 #ifdef LTC_CLEAN_STACK
g_func(ulong32 x,const symmetric_key * key)325 static ulong32 g_func(ulong32 x, const symmetric_key *key)
326 {
327 ulong32 y;
328 y = _g_func(x, key);
329 burn_stack(sizeof(unsigned char) * 4 + sizeof(ulong32));
330 return y;
331 }
332 #endif /* LTC_CLEAN_STACK */
333
334 #endif /* LTC_TWOFISH_SMALL */
335
336 /**
337 Initialize the Twofish block cipher
338 @param key The symmetric key you wish to pass
339 @param keylen The key length in bytes
340 @param num_rounds The number of rounds desired (0 for default)
341 @param skey The key in as scheduled by this function.
342 @return CRYPT_OK if successful
343 */
344 #ifdef LTC_CLEAN_STACK
_twofish_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)345 static int _twofish_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
346 #else
347 int twofish_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
348 #endif
349 {
350 #ifndef LTC_TWOFISH_SMALL
351 unsigned char S[4*4], tmpx0, tmpx1;
352 #endif
353 int k, x, y;
354 unsigned char tmp[4], tmp2[4], M[8*4];
355 ulong32 A, B;
356
357 LTC_ARGCHK(key != NULL);
358 LTC_ARGCHK(skey != NULL);
359
360 /* invalid arguments? */
361 if (num_rounds != 16 && num_rounds != 0) {
362 return CRYPT_INVALID_ROUNDS;
363 }
364
365 if (keylen != 16 && keylen != 24 && keylen != 32) {
366 return CRYPT_INVALID_KEYSIZE;
367 }
368
369 /* k = keysize/64 [but since our keysize is in bytes...] */
370 k = keylen / 8;
371
372 /* copy the key into M */
373 for (x = 0; x < keylen; x++) {
374 M[x] = key[x] & 255;
375 }
376
377 /* create the S[..] words */
378 #ifndef LTC_TWOFISH_SMALL
379 for (x = 0; x < k; x++) {
380 rs_mult(M+(x*8), S+(x*4));
381 }
382 #else
383 for (x = 0; x < k; x++) {
384 rs_mult(M+(x*8), skey->twofish.S+(x*4));
385 }
386 #endif
387
388 /* make subkeys */
389 for (x = 0; x < 20; x++) {
390 /* A = h(p * 2x, Me) */
391 for (y = 0; y < 4; y++) {
392 tmp[y] = x+x;
393 }
394 h_func(tmp, tmp2, M, k, 0);
395 LOAD32L(A, tmp2);
396
397 /* B = ROL(h(p * (2x + 1), Mo), 8) */
398 for (y = 0; y < 4; y++) {
399 tmp[y] = (unsigned char)(x+x+1);
400 }
401 h_func(tmp, tmp2, M, k, 1);
402 LOAD32L(B, tmp2);
403 B = ROLc(B, 8);
404
405 /* K[2i] = A + B */
406 skey->twofish.K[x+x] = (A + B) & 0xFFFFFFFFUL;
407
408 /* K[2i+1] = (A + 2B) <<< 9 */
409 skey->twofish.K[x+x+1] = ROLc(B + B + A, 9);
410 }
411
412 #ifndef LTC_TWOFISH_SMALL
413 /* make the sboxes (large ram variant) */
414 if (k == 2) {
415 for (x = 0; x < 256; x++) {
416 tmpx0 = (unsigned char)sbox(0, x);
417 tmpx1 = (unsigned char)sbox(1, x);
418 skey->twofish.S[0][x] = mds_column_mult(sbox(1, (sbox(0, tmpx0 ^ S[0]) ^ S[4])),0);
419 skey->twofish.S[1][x] = mds_column_mult(sbox(0, (sbox(0, tmpx1 ^ S[1]) ^ S[5])),1);
420 skey->twofish.S[2][x] = mds_column_mult(sbox(1, (sbox(1, tmpx0 ^ S[2]) ^ S[6])),2);
421 skey->twofish.S[3][x] = mds_column_mult(sbox(0, (sbox(1, tmpx1 ^ S[3]) ^ S[7])),3);
422 }
423 } else if (k == 3) {
424 for (x = 0; x < 256; x++) {
425 tmpx0 = (unsigned char)sbox(0, x);
426 tmpx1 = (unsigned char)sbox(1, x);
427 skey->twofish.S[0][x] = mds_column_mult(sbox(1, (sbox(0, sbox(0, tmpx1 ^ S[0]) ^ S[4]) ^ S[8])),0);
428 skey->twofish.S[1][x] = mds_column_mult(sbox(0, (sbox(0, sbox(1, tmpx1 ^ S[1]) ^ S[5]) ^ S[9])),1);
429 skey->twofish.S[2][x] = mds_column_mult(sbox(1, (sbox(1, sbox(0, tmpx0 ^ S[2]) ^ S[6]) ^ S[10])),2);
430 skey->twofish.S[3][x] = mds_column_mult(sbox(0, (sbox(1, sbox(1, tmpx0 ^ S[3]) ^ S[7]) ^ S[11])),3);
431 }
432 } else {
433 for (x = 0; x < 256; x++) {
434 tmpx0 = (unsigned char)sbox(0, x);
435 tmpx1 = (unsigned char)sbox(1, x);
436 skey->twofish.S[0][x] = mds_column_mult(sbox(1, (sbox(0, sbox(0, sbox(1, tmpx1 ^ S[0]) ^ S[4]) ^ S[8]) ^ S[12])),0);
437 skey->twofish.S[1][x] = mds_column_mult(sbox(0, (sbox(0, sbox(1, sbox(1, tmpx0 ^ S[1]) ^ S[5]) ^ S[9]) ^ S[13])),1);
438 skey->twofish.S[2][x] = mds_column_mult(sbox(1, (sbox(1, sbox(0, sbox(0, tmpx0 ^ S[2]) ^ S[6]) ^ S[10]) ^ S[14])),2);
439 skey->twofish.S[3][x] = mds_column_mult(sbox(0, (sbox(1, sbox(1, sbox(0, tmpx1 ^ S[3]) ^ S[7]) ^ S[11]) ^ S[15])),3);
440 }
441 }
442 #else
443 /* where to start in the sbox layers */
444 /* small ram variant */
445 switch (k) {
446 case 4 : skey->twofish.start = 0; break;
447 case 3 : skey->twofish.start = 1; break;
448 default: skey->twofish.start = 2; break;
449 }
450 #endif
451 return CRYPT_OK;
452 }
453
454 #ifdef LTC_CLEAN_STACK
twofish_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)455 int twofish_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
456 {
457 int x;
458 x = _twofish_setup(key, keylen, num_rounds, skey);
459 burn_stack(sizeof(int) * 7 + sizeof(unsigned char) * 56 + sizeof(ulong32) * 2);
460 return x;
461 }
462 #endif
463
464 /**
465 Encrypts a block of text with Twofish
466 @param pt The input plaintext (16 bytes)
467 @param ct The output ciphertext (16 bytes)
468 @param skey The key as scheduled
469 @return CRYPT_OK if successful
470 */
471 #ifdef LTC_CLEAN_STACK
_twofish_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)472 static int _twofish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
473 #else
474 int twofish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
475 #endif
476 {
477 ulong32 a,b,c,d,ta,tb,tc,td,t1,t2;
478 const ulong32 *k;
479 int r;
480 #if !defined(LTC_TWOFISH_SMALL) && !defined(__GNUC__)
481 const ulong32 *S1, *S2, *S3, *S4;
482 #endif
483
484 LTC_ARGCHK(pt != NULL);
485 LTC_ARGCHK(ct != NULL);
486 LTC_ARGCHK(skey != NULL);
487
488 #if !defined(LTC_TWOFISH_SMALL) && !defined(__GNUC__)
489 S1 = skey->twofish.S[0];
490 S2 = skey->twofish.S[1];
491 S3 = skey->twofish.S[2];
492 S4 = skey->twofish.S[3];
493 #endif
494
495 LOAD32L(a,&pt[0]); LOAD32L(b,&pt[4]);
496 LOAD32L(c,&pt[8]); LOAD32L(d,&pt[12]);
497 a ^= skey->twofish.K[0];
498 b ^= skey->twofish.K[1];
499 c ^= skey->twofish.K[2];
500 d ^= skey->twofish.K[3];
501
502 k = skey->twofish.K + 8;
503 for (r = 8; r != 0; --r) {
504 t2 = g1_func(b, skey);
505 t1 = g_func(a, skey) + t2;
506 c = RORc(c ^ (t1 + k[0]), 1);
507 d = ROLc(d, 1) ^ (t2 + t1 + k[1]);
508
509 t2 = g1_func(d, skey);
510 t1 = g_func(c, skey) + t2;
511 a = RORc(a ^ (t1 + k[2]), 1);
512 b = ROLc(b, 1) ^ (t2 + t1 + k[3]);
513 k += 4;
514 }
515
516 /* output with "undo last swap" */
517 ta = c ^ skey->twofish.K[4];
518 tb = d ^ skey->twofish.K[5];
519 tc = a ^ skey->twofish.K[6];
520 td = b ^ skey->twofish.K[7];
521
522 /* store output */
523 STORE32L(ta,&ct[0]); STORE32L(tb,&ct[4]);
524 STORE32L(tc,&ct[8]); STORE32L(td,&ct[12]);
525
526 return CRYPT_OK;
527 }
528
529 #ifdef LTC_CLEAN_STACK
twofish_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)530 int twofish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
531 {
532 int err = _twofish_ecb_encrypt(pt, ct, skey);
533 burn_stack(sizeof(ulong32) * 10 + sizeof(int));
534 return err;
535 }
536 #endif
537
538 /**
539 Decrypts a block of text with Twofish
540 @param ct The input ciphertext (16 bytes)
541 @param pt The output plaintext (16 bytes)
542 @param skey The key as scheduled
543 @return CRYPT_OK if successful
544 */
545 #ifdef LTC_CLEAN_STACK
_twofish_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)546 static int _twofish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
547 #else
548 int twofish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
549 #endif
550 {
551 ulong32 a,b,c,d,ta,tb,tc,td,t1,t2;
552 const ulong32 *k;
553 int r;
554 #if !defined(LTC_TWOFISH_SMALL) && !defined(__GNUC__)
555 const ulong32 *S1, *S2, *S3, *S4;
556 #endif
557
558 LTC_ARGCHK(pt != NULL);
559 LTC_ARGCHK(ct != NULL);
560 LTC_ARGCHK(skey != NULL);
561
562 #if !defined(LTC_TWOFISH_SMALL) && !defined(__GNUC__)
563 S1 = skey->twofish.S[0];
564 S2 = skey->twofish.S[1];
565 S3 = skey->twofish.S[2];
566 S4 = skey->twofish.S[3];
567 #endif
568
569 /* load input */
570 LOAD32L(ta,&ct[0]); LOAD32L(tb,&ct[4]);
571 LOAD32L(tc,&ct[8]); LOAD32L(td,&ct[12]);
572
573 /* undo undo final swap */
574 a = tc ^ skey->twofish.K[6];
575 b = td ^ skey->twofish.K[7];
576 c = ta ^ skey->twofish.K[4];
577 d = tb ^ skey->twofish.K[5];
578
579 k = skey->twofish.K + 36;
580 for (r = 8; r != 0; --r) {
581 t2 = g1_func(d, skey);
582 t1 = g_func(c, skey) + t2;
583 a = ROLc(a, 1) ^ (t1 + k[2]);
584 b = RORc(b ^ (t2 + t1 + k[3]), 1);
585
586 t2 = g1_func(b, skey);
587 t1 = g_func(a, skey) + t2;
588 c = ROLc(c, 1) ^ (t1 + k[0]);
589 d = RORc(d ^ (t2 + t1 + k[1]), 1);
590 k -= 4;
591 }
592
593 /* pre-white */
594 a ^= skey->twofish.K[0];
595 b ^= skey->twofish.K[1];
596 c ^= skey->twofish.K[2];
597 d ^= skey->twofish.K[3];
598
599 /* store */
600 STORE32L(a, &pt[0]); STORE32L(b, &pt[4]);
601 STORE32L(c, &pt[8]); STORE32L(d, &pt[12]);
602 return CRYPT_OK;
603 }
604
605 #ifdef LTC_CLEAN_STACK
twofish_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)606 int twofish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
607 {
608 int err =_twofish_ecb_decrypt(ct, pt, skey);
609 burn_stack(sizeof(ulong32) * 10 + sizeof(int));
610 return err;
611 }
612 #endif
613
614 /**
615 Performs a self-test of the Twofish block cipher
616 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
617 */
twofish_test(void)618 int twofish_test(void)
619 {
620 #ifndef LTC_TEST
621 return CRYPT_NOP;
622 #else
623 static const struct {
624 int keylen;
625 unsigned char key[32], pt[16], ct[16];
626 } tests[] = {
627 { 16,
628 { 0x9F, 0x58, 0x9F, 0x5C, 0xF6, 0x12, 0x2C, 0x32,
629 0xB6, 0xBF, 0xEC, 0x2F, 0x2A, 0xE8, 0xC3, 0x5A },
630 { 0xD4, 0x91, 0xDB, 0x16, 0xE7, 0xB1, 0xC3, 0x9E,
631 0x86, 0xCB, 0x08, 0x6B, 0x78, 0x9F, 0x54, 0x19 },
632 { 0x01, 0x9F, 0x98, 0x09, 0xDE, 0x17, 0x11, 0x85,
633 0x8F, 0xAA, 0xC3, 0xA3, 0xBA, 0x20, 0xFB, 0xC3 }
634 }, {
635 24,
636 { 0x88, 0xB2, 0xB2, 0x70, 0x6B, 0x10, 0x5E, 0x36,
637 0xB4, 0x46, 0xBB, 0x6D, 0x73, 0x1A, 0x1E, 0x88,
638 0xEF, 0xA7, 0x1F, 0x78, 0x89, 0x65, 0xBD, 0x44 },
639 { 0x39, 0xDA, 0x69, 0xD6, 0xBA, 0x49, 0x97, 0xD5,
640 0x85, 0xB6, 0xDC, 0x07, 0x3C, 0xA3, 0x41, 0xB2 },
641 { 0x18, 0x2B, 0x02, 0xD8, 0x14, 0x97, 0xEA, 0x45,
642 0xF9, 0xDA, 0xAC, 0xDC, 0x29, 0x19, 0x3A, 0x65 }
643 }, {
644 32,
645 { 0xD4, 0x3B, 0xB7, 0x55, 0x6E, 0xA3, 0x2E, 0x46,
646 0xF2, 0xA2, 0x82, 0xB7, 0xD4, 0x5B, 0x4E, 0x0D,
647 0x57, 0xFF, 0x73, 0x9D, 0x4D, 0xC9, 0x2C, 0x1B,
648 0xD7, 0xFC, 0x01, 0x70, 0x0C, 0xC8, 0x21, 0x6F },
649 { 0x90, 0xAF, 0xE9, 0x1B, 0xB2, 0x88, 0x54, 0x4F,
650 0x2C, 0x32, 0xDC, 0x23, 0x9B, 0x26, 0x35, 0xE6 },
651 { 0x6C, 0xB4, 0x56, 0x1C, 0x40, 0xBF, 0x0A, 0x97,
652 0x05, 0x93, 0x1C, 0xB6, 0xD4, 0x08, 0xE7, 0xFA }
653 }
654 };
655
656
657 symmetric_key key;
658 unsigned char tmp[2][16];
659 int err, i, y;
660
661 for (i = 0; i < (int)(sizeof(tests)/sizeof(tests[0])); i++) {
662 if ((err = twofish_setup(tests[i].key, tests[i].keylen, 0, &key)) != CRYPT_OK) {
663 return err;
664 }
665 twofish_ecb_encrypt(tests[i].pt, tmp[0], &key);
666 twofish_ecb_decrypt(tmp[0], tmp[1], &key);
667 if (compare_testvector(tmp[0], 16, tests[i].ct, 16, "Twofish Encrypt", i) != 0 ||
668 compare_testvector(tmp[1], 16, tests[i].pt, 16, "Twofish Decrypt", i) != 0) {
669 return CRYPT_FAIL_TESTVECTOR;
670 }
671 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
672 for (y = 0; y < 16; y++) tmp[0][y] = 0;
673 for (y = 0; y < 1000; y++) twofish_ecb_encrypt(tmp[0], tmp[0], &key);
674 for (y = 0; y < 1000; y++) twofish_ecb_decrypt(tmp[0], tmp[0], &key);
675 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
676 }
677 return CRYPT_OK;
678 #endif
679 }
680
681 /** Terminate the context
682 @param skey The scheduled key
683 */
twofish_done(symmetric_key * skey)684 void twofish_done(symmetric_key *skey)
685 {
686 LTC_UNUSED_PARAM(skey);
687 }
688
689 /**
690 Gets suitable key size
691 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
692 @return CRYPT_OK if the input key size is acceptable.
693 */
twofish_keysize(int * keysize)694 int twofish_keysize(int *keysize)
695 {
696 LTC_ARGCHK(keysize);
697 if (*keysize < 16) {
698 return CRYPT_INVALID_KEYSIZE;
699 }
700 if (*keysize < 24) {
701 *keysize = 16;
702 return CRYPT_OK;
703 }
704 if (*keysize < 32) {
705 *keysize = 24;
706 return CRYPT_OK;
707 }
708 *keysize = 32;
709 return CRYPT_OK;
710 }
711
712 #endif
713
714
715 /* ref: $Format:%D$ */
716 /* git commit: $Format:%H$ */
717 /* commit time: $Format:%ai$ */
718