3 * $Id: icrypt.c,v 1.2 1997/08/04 10:24:22 mdw Exp $
5 * Higher level IDEA encryption
7 * (c) 1997 Mark Wooding
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of `become'
14 * `Become' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `Become' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `become'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.2 1997/08/04 10:24:22 mdw
33 * Sources placed under CVS control.
35 * Revision 1.1 1997/07/21 13:47:49 mdw
40 /*----- Header files ------------------------------------------------------*/
42 /* --- ANSI headers --- */
48 /* --- Local headers --- */
54 /*----- Main code ---------------------------------------------------------*/
56 /* --- @icrypt_init@ --- *
58 * Arguments: @icrypt_job *j@ = pointer to job context block
59 * @unsigned char *k@ = pointer to key data
60 * @const unsigned char *iv@ = pointer to IV
64 * Use: Primes the context block ready for encryption.
67 void icrypt_init(icrypt_job *j, unsigned char *k, const unsigned char *iv)
71 memcpy(j->iv, iv, IDEA_BLKSIZE);
73 memset(j->iv, 0, IDEA_BLKSIZE);
77 /* --- @icrypt_encrypt@ --- *
79 * Arguments: @icrypt_job *j@ = job handle
80 * @const void *src@ = pointer to source buffer
81 * @void *dest@ = pointer to destination buffer
82 * @size_t sz@ = size of buffers to handle
86 * Use: Encrypts data from the source to the destination, using the
87 * key attached to the job handle.
90 void icrypt_encrypt(icrypt_job *j, const void *src, void *dest, size_t sz)
96 /* --- First, use up bytes in the buffer --- */
98 while (j->i < IDEA_BLKSIZE && sz > 0) {
99 *d++ = j->iv[j->i++] ^= *s++;
104 /* --- Now encrypt larger chunks at a time --- */
106 while (sz >= IDEA_BLKSIZE) {
108 /* --- Freshen the IV --- */
110 idea_encrypt(&j->k, j->iv, j->iv);
112 /* --- Now encrypt some more bytes --- */
114 for (i = 0; i < IDEA_BLKSIZE; i++) {
115 *d++ = j->iv[i] ^= *s++;
121 /* --- Do the tail-end bits --- */
123 idea_encrypt(&j->k, j->iv, j->iv);
126 *d++ = j->iv[j->i++] ^= *s++;
131 /* --- @icrypt_decrypt@ --- *
133 * Arguments: @icrypt_job *j@ = job handle
134 * @const void *src@ = pointer to source buffer
135 * @void *dest@ = pointer to destination buffer
136 * @size_t sz@ = size of buffers to handle
140 * Use: Decrypts data from the source to the destination, using
141 * the key attached to the job handle.
144 void icrypt_decrypt(icrypt_job *j, const void *src, void *dest, size_t sz)
151 /* --- First, use up bytes in the buffer --- */
153 while (j->i < IDEA_BLKSIZE && sz > 0) {
155 *d++ = j->iv[j->i] ^ c;
161 /* --- Now encrypt larger chunks at a time --- */
163 while (sz >= IDEA_BLKSIZE) {
165 /* --- Freshen the IV --- */
167 idea_encrypt(&j->k, j->iv, j->iv);
169 /* --- Now encrypt some more bytes --- */
171 for (i = 0; i < IDEA_BLKSIZE; i++) {
180 /* --- Do the tail-end bits --- */
182 idea_encrypt(&j->k, j->iv, j->iv);
186 *d++ = j->iv[j->i] ^ c;
192 /* --- @icrypt_reset@ --- *
194 * Arguments: @icrypt_job *j@ = pointer to job context block
195 * @unsigned char *k@ = pointer to key data, or zero for
197 * @const unsigned char *iv@ = pointer to IV, or zero
201 * Use: Alters the context block. This can be used after recovery
202 * of a session key, for example.
205 void icrypt_reset(icrypt_job *j, unsigned char *k, const unsigned char *iv)
208 idea_ekeys(&j->k, k);
210 memcpy(j->iv, iv, IDEA_BLKSIZE);
212 unsigned char b[IDEA_BLKSIZE];
213 int n = j->i, o = IDEA_BLKSIZE - j->i;
215 memcpy(b, j->iv, sizeof(b));
216 memcpy(j->iv, b + n, o);
217 memcpy(j->iv + o, b, n);
222 /* --- @icrypt_saveIV@ --- *
224 * Arguments: @icrypt_job *j@ = pointer to job context block
225 * @unsigned char *iv@ = where to store the IV
229 * Use: Writes out the job's IV after munging it a little.
232 void icrypt_saveIV(icrypt_job *j, unsigned char *iv)
234 int n = j->i, o = IDEA_BLKSIZE - j->i;
236 memcpy(j->iv, iv + n, o);
237 memcpy(j->iv + o, iv, n);
238 idea_encrypt(&j->k, iv, iv);
241 /*----- Test rig ----------------------------------------------------------*/
252 void icrypt(icrypt_job *j,
253 void (*proc)(icrypt_job *j,
263 r = fread(buff, 1, sizeof(buff), fp);
265 proc(j, buff, buff, r);
266 fwrite(buff, 1, r, stdout);
270 int main(int argc, char *argv[])
274 void (*proc)(icrypt_job *j,
277 size_t sz) = icrypt_encrypt;
282 int i = getopt(argc, argv, "d");
286 proc = icrypt_decrypt;
290 char *pass = getpass("Password: ");
291 unsigned char k[IDEA_KEYSIZE];
293 md5_buffer(&md, pass, strlen(pass));
294 memset(pass, 0, strlen(pass));
297 icrypt_init(&j, k, 0);
301 icrypt(&j, proc, stdin);
303 while (optind < argc) {
304 char *p = argv[optind++];
305 if (strcmp(p, "-") == 0)
306 icrypt(&j, proc, stdin);
308 FILE *fp = fopen(p, "rb");
310 die("couldn't open `%s': %s", p, strerror(errno));
311 icrypt(&j, proc, fp);
321 /*----- That's all, folks -------------------------------------------------*/