Mercurial > hg > octave-nkf > gnulib-hg
annotate lib/arcfour.c @ 8051:9c2b0396b27c
Stylistic change: Use '#if HAVE_*' instead of '#ifdef HAVE_*'.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Tue, 30 Jan 2007 01:07:22 +0000 |
| parents | a88f85e4728f |
| children | e8d2c6fc33ad |
| rev | line source |
|---|---|
| 6377 | 1 /* arcfour.c --- The arcfour stream cipher |
|
7584
a88f85e4728f
* lib/arcfour.c: Assume config.h.
Eric Blake <ebb9@byu.net>
parents:
6423
diff
changeset
|
2 * Copyright (C) 2000, 2001, 2002, 2003, 2005, 2006 Free Software |
|
a88f85e4728f
* lib/arcfour.c: Assume config.h.
Eric Blake <ebb9@byu.net>
parents:
6423
diff
changeset
|
3 * Foundation, Inc. |
| 6377 | 4 * |
| 5 * This file is free software; you can redistribute it and/or modify | |
| 6 * it under the terms of the GNU General Public License as published | |
| 7 * by the Free Software Foundation; either version 2, or (at your | |
| 8 * option) any later version. | |
| 9 * | |
| 10 * This file is distributed in the hope that it will be useful, but | |
| 11 * WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 * General Public License for more details. | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License | |
| 16 * along with this file; if not, write to the Free Software | |
| 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
| 18 * 02110-1301, USA. | |
| 19 * | |
| 20 */ | |
| 21 | |
| 22 /* Code from Libgcrypt adapted for gnulib by Simon Josefsson. */ | |
| 23 | |
| 24 /* | |
| 25 * For a description of the algorithm, see: | |
| 26 * Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996. | |
| 27 * ISBN 0-471-11709-9. Pages 397 ff. | |
| 28 */ | |
| 29 | |
|
7584
a88f85e4728f
* lib/arcfour.c: Assume config.h.
Eric Blake <ebb9@byu.net>
parents:
6423
diff
changeset
|
30 #include <config.h> |
| 6377 | 31 |
| 32 #include "arcfour.h" | |
| 33 | |
| 34 void | |
| 35 arcfour_stream (arcfour_context * context, const char *inbuf, char *outbuf, | |
| 36 size_t length) | |
| 37 { | |
| 6423 | 38 uint8_t i = context->idx_i; |
| 39 uint8_t j = context->idx_j; | |
| 6377 | 40 char *sbox = context->sbox; |
| 41 | |
| 42 for (; length > 0; length--) | |
| 43 { | |
| 44 char t; | |
| 45 | |
| 6423 | 46 i++; |
| 47 j += sbox[i]; | |
| 6377 | 48 t = sbox[i]; |
| 49 sbox[i] = sbox[j]; | |
| 50 sbox[j] = t; | |
| 51 *outbuf++ = (*inbuf++ | |
| 52 ^ sbox[(0U + sbox[i] + sbox[j]) % ARCFOUR_SBOX_SIZE]); | |
| 53 } | |
| 54 | |
| 55 context->idx_i = i; | |
| 56 context->idx_j = j; | |
| 57 } | |
| 58 | |
| 59 void | |
| 60 arcfour_setkey (arcfour_context * context, const char *key, size_t keylen) | |
| 61 { | |
| 62 size_t i, j, k; | |
| 63 char *sbox = context->sbox; | |
| 64 | |
| 65 context->idx_i = context->idx_j = 0; | |
| 66 for (i = 0; i < ARCFOUR_SBOX_SIZE; i++) | |
| 67 sbox[i] = i; | |
| 68 for (i = j = k = 0; i < ARCFOUR_SBOX_SIZE; i++) | |
| 69 { | |
| 70 char t; | |
| 71 j = (j + sbox[i] + key[k]) % ARCFOUR_SBOX_SIZE; | |
| 72 t = sbox[i]; | |
| 73 sbox[i] = sbox[j]; | |
| 74 sbox[j] = t; | |
| 75 if (++k == keylen) | |
| 76 k = 0; | |
| 77 } | |
| 78 } |