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comparison src/ciphers/safer/saferp.c @ 192:9cc34777b479 libtomcrypt

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propagate from branch 'au.asn.ucc.matt.ltc-orig' (head 9ba8f01f44320e9cb9f19881105ae84f84a43ea9) to branch 'au.asn.ucc.matt.dropbear.ltc' (head dbf51c569bc34956ad948e4cc87a0eeb2170b768)
author Matt Johnston <matt@ucc.asn.au>
date Sun, 08 May 2005 06:36:47 +0000
parents 1c15b283127b
children 39d5d58461d6
comparison
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164:cd1143579f00 192:9cc34777b479
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11
12 /**
13 @file saferp.c
14 SAFER+ Implementation by Tom St Denis
15 */
16 #include "tomcrypt.h"
17
18 #ifdef SAFERP
19
20 const struct ltc_cipher_descriptor saferp_desc =
21 {
22 "safer+",
23 4,
24 16, 32, 16, 8,
25 &saferp_setup,
26 &saferp_ecb_encrypt,
27 &saferp_ecb_decrypt,
28 &saferp_test,
29 &saferp_done,
30 &saferp_keysize,
31 NULL, NULL, NULL, NULL, NULL, NULL, NULL
32 };
33
34 /* ROUND(b,i)
35 *
36 * This is one forward key application. Note the basic form is
37 * key addition, substitution, key addition. The safer_ebox and safer_lbox
38 * are the exponentiation box and logarithm boxes respectively.
39 * The value of 'i' is the current round number which allows this
40 * function to be unrolled massively. Most of SAFER+'s speed
41 * comes from not having to compute indirect accesses into the
42 * array of 16 bytes b[0..15] which is the block of data
43 */
44
45 extern const unsigned char safer_ebox[], safer_lbox[];
46
47 #define ROUND(b, i) \
48 b[0] = (safer_ebox[(b[0] ^ skey->saferp.K[i][0]) & 255] + skey->saferp.K[i+1][0]) & 255; \
49 b[1] = safer_lbox[(b[1] + skey->saferp.K[i][1]) & 255] ^ skey->saferp.K[i+1][1]; \
50 b[2] = safer_lbox[(b[2] + skey->saferp.K[i][2]) & 255] ^ skey->saferp.K[i+1][2]; \
51 b[3] = (safer_ebox[(b[3] ^ skey->saferp.K[i][3]) & 255] + skey->saferp.K[i+1][3]) & 255; \
52 b[4] = (safer_ebox[(b[4] ^ skey->saferp.K[i][4]) & 255] + skey->saferp.K[i+1][4]) & 255; \
53 b[5] = safer_lbox[(b[5] + skey->saferp.K[i][5]) & 255] ^ skey->saferp.K[i+1][5]; \
54 b[6] = safer_lbox[(b[6] + skey->saferp.K[i][6]) & 255] ^ skey->saferp.K[i+1][6]; \
55 b[7] = (safer_ebox[(b[7] ^ skey->saferp.K[i][7]) & 255] + skey->saferp.K[i+1][7]) & 255; \
56 b[8] = (safer_ebox[(b[8] ^ skey->saferp.K[i][8]) & 255] + skey->saferp.K[i+1][8]) & 255; \
57 b[9] = safer_lbox[(b[9] + skey->saferp.K[i][9]) & 255] ^ skey->saferp.K[i+1][9]; \
58 b[10] = safer_lbox[(b[10] + skey->saferp.K[i][10]) & 255] ^ skey->saferp.K[i+1][10]; \
59 b[11] = (safer_ebox[(b[11] ^ skey->saferp.K[i][11]) & 255] + skey->saferp.K[i+1][11]) & 255; \
60 b[12] = (safer_ebox[(b[12] ^ skey->saferp.K[i][12]) & 255] + skey->saferp.K[i+1][12]) & 255; \
61 b[13] = safer_lbox[(b[13] + skey->saferp.K[i][13]) & 255] ^ skey->saferp.K[i+1][13]; \
62 b[14] = safer_lbox[(b[14] + skey->saferp.K[i][14]) & 255] ^ skey->saferp.K[i+1][14]; \
63 b[15] = (safer_ebox[(b[15] ^ skey->saferp.K[i][15]) & 255] + skey->saferp.K[i+1][15]) & 255;
64
65 /* This is one inverse key application */
66 #define iROUND(b, i) \
67 b[0] = safer_lbox[(b[0] - skey->saferp.K[i+1][0]) & 255] ^ skey->saferp.K[i][0]; \
68 b[1] = (safer_ebox[(b[1] ^ skey->saferp.K[i+1][1]) & 255] - skey->saferp.K[i][1]) & 255; \
69 b[2] = (safer_ebox[(b[2] ^ skey->saferp.K[i+1][2]) & 255] - skey->saferp.K[i][2]) & 255; \
70 b[3] = safer_lbox[(b[3] - skey->saferp.K[i+1][3]) & 255] ^ skey->saferp.K[i][3]; \
71 b[4] = safer_lbox[(b[4] - skey->saferp.K[i+1][4]) & 255] ^ skey->saferp.K[i][4]; \
72 b[5] = (safer_ebox[(b[5] ^ skey->saferp.K[i+1][5]) & 255] - skey->saferp.K[i][5]) & 255; \
73 b[6] = (safer_ebox[(b[6] ^ skey->saferp.K[i+1][6]) & 255] - skey->saferp.K[i][6]) & 255; \
74 b[7] = safer_lbox[(b[7] - skey->saferp.K[i+1][7]) & 255] ^ skey->saferp.K[i][7]; \
75 b[8] = safer_lbox[(b[8] - skey->saferp.K[i+1][8]) & 255] ^ skey->saferp.K[i][8]; \
76 b[9] = (safer_ebox[(b[9] ^ skey->saferp.K[i+1][9]) & 255] - skey->saferp.K[i][9]) & 255; \
77 b[10] = (safer_ebox[(b[10] ^ skey->saferp.K[i+1][10]) & 255] - skey->saferp.K[i][10]) & 255; \
78 b[11] = safer_lbox[(b[11] - skey->saferp.K[i+1][11]) & 255] ^ skey->saferp.K[i][11]; \
79 b[12] = safer_lbox[(b[12] - skey->saferp.K[i+1][12]) & 255] ^ skey->saferp.K[i][12]; \
80 b[13] = (safer_ebox[(b[13] ^ skey->saferp.K[i+1][13]) & 255] - skey->saferp.K[i][13]) & 255; \
81 b[14] = (safer_ebox[(b[14] ^ skey->saferp.K[i+1][14]) & 255] - skey->saferp.K[i][14]) & 255; \
82 b[15] = safer_lbox[(b[15] - skey->saferp.K[i+1][15]) & 255] ^ skey->saferp.K[i][15];
83
84 /* This is a forward single layer PHT transform. */
85 #define PHT(b) \
86 b[0] = (b[0] + (b[1] = (b[0] + b[1]) & 255)) & 255; \
87 b[2] = (b[2] + (b[3] = (b[3] + b[2]) & 255)) & 255; \
88 b[4] = (b[4] + (b[5] = (b[5] + b[4]) & 255)) & 255; \
89 b[6] = (b[6] + (b[7] = (b[7] + b[6]) & 255)) & 255; \
90 b[8] = (b[8] + (b[9] = (b[9] + b[8]) & 255)) & 255; \
91 b[10] = (b[10] + (b[11] = (b[11] + b[10]) & 255)) & 255; \
92 b[12] = (b[12] + (b[13] = (b[13] + b[12]) & 255)) & 255; \
93 b[14] = (b[14] + (b[15] = (b[15] + b[14]) & 255)) & 255;
94
95 /* This is an inverse single layer PHT transform */
96 #define iPHT(b) \
97 b[15] = (b[15] - (b[14] = (b[14] - b[15]) & 255)) & 255; \
98 b[13] = (b[13] - (b[12] = (b[12] - b[13]) & 255)) & 255; \
99 b[11] = (b[11] - (b[10] = (b[10] - b[11]) & 255)) & 255; \
100 b[9] = (b[9] - (b[8] = (b[8] - b[9]) & 255)) & 255; \
101 b[7] = (b[7] - (b[6] = (b[6] - b[7]) & 255)) & 255; \
102 b[5] = (b[5] - (b[4] = (b[4] - b[5]) & 255)) & 255; \
103 b[3] = (b[3] - (b[2] = (b[2] - b[3]) & 255)) & 255; \
104 b[1] = (b[1] - (b[0] = (b[0] - b[1]) & 255)) & 255; \
105
106 /* This is the "Armenian" Shuffle. It takes the input from b and stores it in b2 */
107 #define SHUF(b, b2) \
108 b2[0] = b[8]; b2[1] = b[11]; b2[2] = b[12]; b2[3] = b[15]; \
109 b2[4] = b[2]; b2[5] = b[1]; b2[6] = b[6]; b2[7] = b[5]; \
110 b2[8] = b[10]; b2[9] = b[9]; b2[10] = b[14]; b2[11] = b[13]; \
111 b2[12] = b[0]; b2[13] = b[7]; b2[14] = b[4]; b2[15] = b[3];
112
113 /* This is the inverse shuffle. It takes from b and gives to b2 */
114 #define iSHUF(b, b2) \
115 b2[0] = b[12]; b2[1] = b[5]; b2[2] = b[4]; b2[3] = b[15]; \
116 b2[4] = b[14]; b2[5] = b[7]; b2[6] = b[6]; b2[7] = b[13]; \
117 b2[8] = b[0]; b2[9] = b[9]; b2[10] = b[8]; b2[11] = b[1]; \
118 b2[12] = b[2]; b2[13] = b[11]; b2[14] = b[10]; b2[15] = b[3];
119
120 /* The complete forward Linear Transform layer.
121 * Note that alternating usage of b and b2.
122 * Each round of LT starts in 'b' and ends in 'b2'.
123 */
124 #define LT(b, b2) \
125 PHT(b); SHUF(b, b2); \
126 PHT(b2); SHUF(b2, b); \
127 PHT(b); SHUF(b, b2); \
128 PHT(b2);
129
130 /* This is the inverse linear transform layer. */
131 #define iLT(b, b2) \
132 iPHT(b); \
133 iSHUF(b, b2); iPHT(b2); \
134 iSHUF(b2, b); iPHT(b); \
135 iSHUF(b, b2); iPHT(b2);
136
137 #ifdef LTC_SMALL_CODE
138
139 static void _round(unsigned char *b, int i, symmetric_key *skey)
140 {
141 ROUND(b, i);
142 }
143
144 static void _iround(unsigned char *b, int i, symmetric_key *skey)
145 {
146 iROUND(b, i);
147 }
148
149 static void _lt(unsigned char *b, unsigned char *b2)
150 {
151 LT(b, b2);
152 }
153
154 static void _ilt(unsigned char *b, unsigned char *b2)
155 {
156 iLT(b, b2);
157 }
158
159 #undef ROUND
160 #define ROUND(b, i) _round(b, i, skey)
161
162 #undef iROUND
163 #define iROUND(b, i) _iround(b, i, skey)
164
165 #undef LT
166 #define LT(b, b2) _lt(b, b2)
167
168 #undef iLT
169 #define iLT(b, b2) _ilt(b, b2)
170
171 #endif
172
173 /* These are the 33, 128-bit bias words for the key schedule */
174 static const unsigned char safer_bias[33][16] = {
175 { 70, 151, 177, 186, 163, 183, 16, 10, 197, 55, 179, 201, 90, 40, 172, 100},
176 { 236, 171, 170, 198, 103, 149, 88, 13, 248, 154, 246, 110, 102, 220, 5, 61},
177 { 138, 195, 216, 137, 106, 233, 54, 73, 67, 191, 235, 212, 150, 155, 104, 160},
178 { 93, 87, 146, 31, 213, 113, 92, 187, 34, 193, 190, 123, 188, 153, 99, 148},
179 { 42, 97, 184, 52, 50, 25, 253, 251, 23, 64, 230, 81, 29, 65, 68, 143},
180 { 221, 4, 128, 222, 231, 49, 214, 127, 1, 162, 247, 57, 218, 111, 35, 202},
181 { 58, 208, 28, 209, 48, 62, 18, 161, 205, 15, 224, 168, 175, 130, 89, 44},
182 { 125, 173, 178, 239, 194, 135, 206, 117, 6, 19, 2, 144, 79, 46, 114, 51},
183 { 192, 141, 207, 169, 129, 226, 196, 39, 47, 108, 122, 159, 82, 225, 21, 56},
184 { 252, 32, 66, 199, 8, 228, 9, 85, 94, 140, 20, 118, 96, 255, 223, 215},
185 { 250, 11, 33, 0, 26, 249, 166, 185, 232, 158, 98, 76, 217, 145, 80, 210},
186 { 24, 180, 7, 132, 234, 91, 164, 200, 14, 203, 72, 105, 75, 78, 156, 53},
187 { 69, 77, 84, 229, 37, 60, 12, 74, 139, 63, 204, 167, 219, 107, 174, 244},
188 { 45, 243, 124, 109, 157, 181, 38, 116, 242, 147, 83, 176, 240, 17, 237, 131},
189 { 182, 3, 22, 115, 59, 30, 142, 112, 189, 134, 27, 71, 126, 36, 86, 241},
190 { 136, 70, 151, 177, 186, 163, 183, 16, 10, 197, 55, 179, 201, 90, 40, 172},
191 { 220, 134, 119, 215, 166, 17, 251, 244, 186, 146, 145, 100, 131, 241, 51, 239},
192 { 44, 181, 178, 43, 136, 209, 153, 203, 140, 132, 29, 20, 129, 151, 113, 202},
193 { 163, 139, 87, 60, 130, 196, 82, 92, 28, 232, 160, 4, 180, 133, 74, 246},
194 { 84, 182, 223, 12, 26, 142, 222, 224, 57, 252, 32, 155, 36, 78, 169, 152},
195 { 171, 242, 96, 208, 108, 234, 250, 199, 217, 0, 212, 31, 110, 67, 188, 236},
196 { 137, 254, 122, 93, 73, 201, 50, 194, 249, 154, 248, 109, 22, 219, 89, 150},
197 { 233, 205, 230, 70, 66, 143, 10, 193, 204, 185, 101, 176, 210, 198, 172, 30},
198 { 98, 41, 46, 14, 116, 80, 2, 90, 195, 37, 123, 138, 42, 91, 240, 6},
199 { 71, 111, 112, 157, 126, 16, 206, 18, 39, 213, 76, 79, 214, 121, 48, 104},
200 { 117, 125, 228, 237, 128, 106, 144, 55, 162, 94, 118, 170, 197, 127, 61, 175},
201 { 229, 25, 97, 253, 77, 124, 183, 11, 238, 173, 75, 34, 245, 231, 115, 35},
202 { 200, 5, 225, 102, 221, 179, 88, 105, 99, 86, 15, 161, 49, 149, 23, 7},
203 { 40, 1, 45, 226, 147, 190, 69, 21, 174, 120, 3, 135, 164, 184, 56, 207},
204 { 8, 103, 9, 148, 235, 38, 168, 107, 189, 24, 52, 27, 187, 191, 114, 247},
205 { 53, 72, 156, 81, 47, 59, 85, 227, 192, 159, 216, 211, 243, 141, 177, 255},
206 { 62, 220, 134, 119, 215, 166, 17, 251, 244, 186, 146, 145, 100, 131, 241, 51}};
207
208 /**
209 Initialize the SAFER+ block cipher
210 @param key The symmetric key you wish to pass
211 @param keylen The key length in bytes
212 @param num_rounds The number of rounds desired (0 for default)
213 @param skey The key in as scheduled by this function.
214 @return CRYPT_OK if successful
215 */
216 int saferp_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
217 {
218 unsigned x, y, z;
219 unsigned char t[33];
220 static const int rounds[3] = { 8, 12, 16 };
221
222 LTC_ARGCHK(key != NULL);
223 LTC_ARGCHK(skey != NULL);
224
225 /* check arguments */
226 if (keylen != 16 && keylen != 24 && keylen != 32) {
227 return CRYPT_INVALID_KEYSIZE;
228 }
229
230 /* Is the number of rounds valid? Either use zero for default or
231 * 8,12,16 rounds for 16,24,32 byte keys
232 */
233 if (num_rounds != 0 && num_rounds != rounds[(keylen/8)-2]) {
234 return CRYPT_INVALID_ROUNDS;
235 }
236
237 /* 128 bit key version */
238 if (keylen == 16) {
239 /* copy key into t */
240 for (x = y = 0; x < 16; x++) {
241 t[x] = key[x];
242 y ^= key[x];
243 }
244 t[16] = y;
245
246 /* make round keys */
247 for (x = 0; x < 16; x++) {
248 skey->saferp.K[0][x] = t[x];
249 }
250
251 /* make the 16 other keys as a transformation of the first key */
252 for (x = 1; x < 17; x++) {
253 /* rotate 3 bits each */
254 for (y = 0; y < 17; y++) {
255 t[y] = ((t[y]<<3)|(t[y]>>5)) & 255;
256 }
257
258 /* select and add */
259 z = x;
260 for (y = 0; y < 16; y++) {
261 skey->saferp.K[x][y] = (t[z] + safer_bias[x-1][y]) & 255;
262 if (++z == 17) { z = 0; }
263 }
264 }
265 skey->saferp.rounds = 8;
266 } else if (keylen == 24) {
267 /* copy key into t */
268 for (x = y = 0; x < 24; x++) {
269 t[x] = key[x];
270 y ^= key[x];
271 }
272 t[24] = y;
273
274 /* make round keys */
275 for (x = 0; x < 16; x++) {
276 skey->saferp.K[0][x] = t[x];
277 }
278
279 for (x = 1; x < 25; x++) {
280 /* rotate 3 bits each */
281 for (y = 0; y < 25; y++) {
282 t[y] = ((t[y]<<3)|(t[y]>>5)) & 255;
283 }
284
285 /* select and add */
286 z = x;
287 for (y = 0; y < 16; y++) {
288 skey->saferp.K[x][y] = (t[z] + safer_bias[x-1][y]) & 255;
289 if (++z == 25) { z = 0; }
290 }
291 }
292 skey->saferp.rounds = 12;
293 } else {
294 /* copy key into t */
295 for (x = y = 0; x < 32; x++) {
296 t[x] = key[x];
297 y ^= key[x];
298 }
299 t[32] = y;
300
301 /* make round keys */
302 for (x = 0; x < 16; x++) {
303 skey->saferp.K[0][x] = t[x];
304 }
305
306 for (x = 1; x < 33; x++) {
307 /* rotate 3 bits each */
308 for (y = 0; y < 33; y++) {
309 t[y] = ((t[y]<<3)|(t[y]>>5)) & 255;
310 }
311
312 /* select and add */
313 z = x;
314 for (y = 0; y < 16; y++) {
315 skey->saferp.K[x][y] = (t[z] + safer_bias[x-1][y]) & 255;
316 if (++z == 33) { z = 0; }
317 }
318 }
319 skey->saferp.rounds = 16;
320 }
321 #ifdef LTC_CLEAN_STACK
322 zeromem(t, sizeof(t));
323 #endif
324 return CRYPT_OK;
325 }
326
327 /**
328 Encrypts a block of text with SAFER+
329 @param pt The input plaintext (16 bytes)
330 @param ct The output ciphertext (16 bytes)
331 @param skey The key as scheduled
332 */
333 void saferp_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
334 {
335 unsigned char b[16];
336 int x;
337
338 LTC_ARGCHK(pt != NULL);
339 LTC_ARGCHK(ct != NULL);
340 LTC_ARGCHK(skey != NULL);
341
342 /* do eight rounds */
343 for (x = 0; x < 16; x++) {
344 b[x] = pt[x];
345 }
346 ROUND(b, 0); LT(b, ct);
347 ROUND(ct, 2); LT(ct, b);
348 ROUND(b, 4); LT(b, ct);
349 ROUND(ct, 6); LT(ct, b);
350 ROUND(b, 8); LT(b, ct);
351 ROUND(ct, 10); LT(ct, b);
352 ROUND(b, 12); LT(b, ct);
353 ROUND(ct, 14); LT(ct, b);
354 /* 192-bit key? */
355 if (skey->saferp.rounds > 8) {
356 ROUND(b, 16); LT(b, ct);
357 ROUND(ct, 18); LT(ct, b);
358 ROUND(b, 20); LT(b, ct);
359 ROUND(ct, 22); LT(ct, b);
360 }
361 /* 256-bit key? */
362 if (skey->saferp.rounds > 12) {
363 ROUND(b, 24); LT(b, ct);
364 ROUND(ct, 26); LT(ct, b);
365 ROUND(b, 28); LT(b, ct);
366 ROUND(ct, 30); LT(ct, b);
367 }
368 ct[0] = b[0] ^ skey->saferp.K[skey->saferp.rounds*2][0];
369 ct[1] = (b[1] + skey->saferp.K[skey->saferp.rounds*2][1]) & 255;
370 ct[2] = (b[2] + skey->saferp.K[skey->saferp.rounds*2][2]) & 255;
371 ct[3] = b[3] ^ skey->saferp.K[skey->saferp.rounds*2][3];
372 ct[4] = b[4] ^ skey->saferp.K[skey->saferp.rounds*2][4];
373 ct[5] = (b[5] + skey->saferp.K[skey->saferp.rounds*2][5]) & 255;
374 ct[6] = (b[6] + skey->saferp.K[skey->saferp.rounds*2][6]) & 255;
375 ct[7] = b[7] ^ skey->saferp.K[skey->saferp.rounds*2][7];
376 ct[8] = b[8] ^ skey->saferp.K[skey->saferp.rounds*2][8];
377 ct[9] = (b[9] + skey->saferp.K[skey->saferp.rounds*2][9]) & 255;
378 ct[10] = (b[10] + skey->saferp.K[skey->saferp.rounds*2][10]) & 255;
379 ct[11] = b[11] ^ skey->saferp.K[skey->saferp.rounds*2][11];
380 ct[12] = b[12] ^ skey->saferp.K[skey->saferp.rounds*2][12];
381 ct[13] = (b[13] + skey->saferp.K[skey->saferp.rounds*2][13]) & 255;
382 ct[14] = (b[14] + skey->saferp.K[skey->saferp.rounds*2][14]) & 255;
383 ct[15] = b[15] ^ skey->saferp.K[skey->saferp.rounds*2][15];
384 #ifdef LTC_CLEAN_STACK
385 zeromem(b, sizeof(b));
386 #endif
387 }
388
389 /**
390 Decrypts a block of text with SAFER+
391 @param ct The input ciphertext (16 bytes)
392 @param pt The output plaintext (16 bytes)
393 @param skey The key as scheduled
394 */
395 void saferp_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
396 {
397 unsigned char b[16];
398 int x;
399
400 LTC_ARGCHK(pt != NULL);
401 LTC_ARGCHK(ct != NULL);
402 LTC_ARGCHK(skey != NULL);
403
404 /* do eight rounds */
405 b[0] = ct[0] ^ skey->saferp.K[skey->saferp.rounds*2][0];
406 b[1] = (ct[1] - skey->saferp.K[skey->saferp.rounds*2][1]) & 255;
407 b[2] = (ct[2] - skey->saferp.K[skey->saferp.rounds*2][2]) & 255;
408 b[3] = ct[3] ^ skey->saferp.K[skey->saferp.rounds*2][3];
409 b[4] = ct[4] ^ skey->saferp.K[skey->saferp.rounds*2][4];
410 b[5] = (ct[5] - skey->saferp.K[skey->saferp.rounds*2][5]) & 255;
411 b[6] = (ct[6] - skey->saferp.K[skey->saferp.rounds*2][6]) & 255;
412 b[7] = ct[7] ^ skey->saferp.K[skey->saferp.rounds*2][7];
413 b[8] = ct[8] ^ skey->saferp.K[skey->saferp.rounds*2][8];
414 b[9] = (ct[9] - skey->saferp.K[skey->saferp.rounds*2][9]) & 255;
415 b[10] = (ct[10] - skey->saferp.K[skey->saferp.rounds*2][10]) & 255;
416 b[11] = ct[11] ^ skey->saferp.K[skey->saferp.rounds*2][11];
417 b[12] = ct[12] ^ skey->saferp.K[skey->saferp.rounds*2][12];
418 b[13] = (ct[13] - skey->saferp.K[skey->saferp.rounds*2][13]) & 255;
419 b[14] = (ct[14] - skey->saferp.K[skey->saferp.rounds*2][14]) & 255;
420 b[15] = ct[15] ^ skey->saferp.K[skey->saferp.rounds*2][15];
421 /* 256-bit key? */
422 if (skey->saferp.rounds > 12) {
423 iLT(b, pt); iROUND(pt, 30);
424 iLT(pt, b); iROUND(b, 28);
425 iLT(b, pt); iROUND(pt, 26);
426 iLT(pt, b); iROUND(b, 24);
427 }
428 /* 192-bit key? */
429 if (skey->saferp.rounds > 8) {
430 iLT(b, pt); iROUND(pt, 22);
431 iLT(pt, b); iROUND(b, 20);
432 iLT(b, pt); iROUND(pt, 18);
433 iLT(pt, b); iROUND(b, 16);
434 }
435 iLT(b, pt); iROUND(pt, 14);
436 iLT(pt, b); iROUND(b, 12);
437 iLT(b, pt); iROUND(pt,10);
438 iLT(pt, b); iROUND(b, 8);
439 iLT(b, pt); iROUND(pt,6);
440 iLT(pt, b); iROUND(b, 4);
441 iLT(b, pt); iROUND(pt,2);
442 iLT(pt, b); iROUND(b, 0);
443 for (x = 0; x < 16; x++) {
444 pt[x] = b[x];
445 }
446 #ifdef LTC_CLEAN_STACK
447 zeromem(b, sizeof(b));
448 #endif
449 }
450
451 /**
452 Performs a self-test of the SAFER+ block cipher
453 @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
454 */
455 int saferp_test(void)
456 {
457 #ifndef LTC_TEST
458 return CRYPT_NOP;
459 #else
460 static const struct {
461 int keylen;
462 unsigned char key[32], pt[16], ct[16];
463 } tests[] = {
464 {
465 16,
466 { 41, 35, 190, 132, 225, 108, 214, 174,
467 82, 144, 73, 241, 241, 187, 233, 235 },
468 { 179, 166, 219, 60, 135, 12, 62, 153,
469 36, 94, 13, 28, 6, 183, 71, 222 },
470 { 224, 31, 182, 10, 12, 255, 84, 70,
471 127, 13, 89, 249, 9, 57, 165, 220 }
472 }, {
473 24,
474 { 72, 211, 143, 117, 230, 217, 29, 42,
475 229, 192, 247, 43, 120, 129, 135, 68,
476 14, 95, 80, 0, 212, 97, 141, 190 },
477 { 123, 5, 21, 7, 59, 51, 130, 31,
478 24, 112, 146, 218, 100, 84, 206, 177 },
479 { 92, 136, 4, 63, 57, 95, 100, 0,
480 150, 130, 130, 16, 193, 111, 219, 133 }
481 }, {
482 32,
483 { 243, 168, 141, 254, 190, 242, 235, 113,
484 255, 160, 208, 59, 117, 6, 140, 126,
485 135, 120, 115, 77, 208, 190, 130, 190,
486 219, 194, 70, 65, 43, 140, 250, 48 },
487 { 127, 112, 240, 167, 84, 134, 50, 149,
488 170, 91, 104, 19, 11, 230, 252, 245 },
489 { 88, 11, 25, 36, 172, 229, 202, 213,
490 170, 65, 105, 153, 220, 104, 153, 138 }
491 }
492 };
493
494 unsigned char tmp[2][16];
495 symmetric_key skey;
496 int err, i, y;
497
498 for (i = 0; i < (int)(sizeof(tests) / sizeof(tests[0])); i++) {
499 if ((err = saferp_setup(tests[i].key, tests[i].keylen, 0, &skey)) != CRYPT_OK) {
500 return err;
501 }
502 saferp_ecb_encrypt(tests[i].pt, tmp[0], &skey);
503 saferp_ecb_decrypt(tmp[0], tmp[1], &skey);
504
505 /* compare */
506 if (memcmp(tmp[0], tests[i].ct, 16) || memcmp(tmp[1], tests[i].pt, 16)) {
507 return CRYPT_FAIL_TESTVECTOR;
508 }
509
510 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
511 for (y = 0; y < 16; y++) tmp[0][y] = 0;
512 for (y = 0; y < 1000; y++) saferp_ecb_encrypt(tmp[0], tmp[0], &skey);
513 for (y = 0; y < 1000; y++) saferp_ecb_decrypt(tmp[0], tmp[0], &skey);
514 for (y = 0; y < 16; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
515 }
516
517 return CRYPT_OK;
518 #endif
519 }
520
521 /** Terminate the context
522 @param skey The scheduled key
523 */
524 void saferp_done(symmetric_key *skey)
525 {
526 }
527
528 /**
529 Gets suitable key size
530 @param keysize [in/out] The length of the recommended key (in bytes). This function will store the suitable size back in this variable.
531 @return CRYPT_OK if the input key size is acceptable.
532 */
533 int saferp_keysize(int *keysize)
534 {
535 LTC_ARGCHK(keysize != NULL);
536
537 if (*keysize < 16)
538 return CRYPT_INVALID_KEYSIZE;
539 if (*keysize < 24) {
540 *keysize = 16;
541 } else if (*keysize < 32) {
542 *keysize = 24;
543 } else {
544 *keysize = 32;
545 }
546 return CRYPT_OK;
547 }
548
549 #endif
550
551