Mercurial > gnulib
annotate lib/arcfour.c @ 40057:b06060465f09
maint: Run 'make update-copyright'
| author | Paul Eggert <eggert@cs.ucla.edu> |
|---|---|
| date | Tue, 01 Jan 2019 00:25:11 +0100 |
| parents | 10eb9086bea0 |
| children |
| rev | line source |
|---|---|
| 6377 | 1 /* arcfour.c --- The arcfour stream cipher |
|
40057
b06060465f09
maint: Run 'make update-copyright'
Paul Eggert <eggert@cs.ucla.edu>
parents:
19484
diff
changeset
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2 * Copyright (C) 2000-2003, 2005-2006, 2009-2019 Free Software Foundation, Inc. |
| 6377 | 3 * |
| 4 * This file is free software; you can redistribute it and/or modify | |
| 5 * it under the terms of the GNU General Public License as published | |
| 6 * by the Free Software Foundation; either version 2, or (at your | |
| 7 * option) any later version. | |
| 8 * | |
| 9 * This file is distributed in the hope that it will be useful, but | |
| 10 * WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 12 * General Public License for more details. | |
| 13 * | |
| 14 * You should have received a copy of the GNU General Public License | |
| 19190 | 15 * along with this file; if not, see <https://www.gnu.org/licenses/>. |
| 6377 | 16 * |
| 17 */ | |
| 18 | |
| 19 /* Code from Libgcrypt adapted for gnulib by Simon Josefsson. */ | |
| 20 | |
| 21 /* | |
| 22 * For a description of the algorithm, see: | |
| 23 * Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1996. | |
| 24 * ISBN 0-471-11709-9. Pages 397 ff. | |
| 25 */ | |
| 26 | |
|
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* lib/arcfour.c: Assume config.h.
Eric Blake <ebb9@byu.net>
parents:
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diff
changeset
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27 #include <config.h> |
| 6377 | 28 |
| 29 #include "arcfour.h" | |
| 30 | |
| 31 void | |
| 32 arcfour_stream (arcfour_context * context, const char *inbuf, char *outbuf, | |
|
12421
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Use spaces for indentation, not tabs.
Bruno Haible <bruno@clisp.org>
parents:
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changeset
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33 size_t length) |
| 6377 | 34 { |
| 6423 | 35 uint8_t i = context->idx_i; |
| 36 uint8_t j = context->idx_j; | |
| 6377 | 37 char *sbox = context->sbox; |
| 38 | |
| 39 for (; length > 0; length--) | |
| 40 { | |
| 41 char t; | |
| 42 | |
| 6423 | 43 i++; |
| 44 j += sbox[i]; | |
| 6377 | 45 t = sbox[i]; |
| 46 sbox[i] = sbox[j]; | |
| 47 sbox[j] = t; | |
| 48 *outbuf++ = (*inbuf++ | |
|
12421
e8d2c6fc33ad
Use spaces for indentation, not tabs.
Bruno Haible <bruno@clisp.org>
parents:
7584
diff
changeset
|
49 ^ sbox[(0U + sbox[i] + sbox[j]) % ARCFOUR_SBOX_SIZE]); |
| 6377 | 50 } |
| 51 | |
| 52 context->idx_i = i; | |
| 53 context->idx_j = j; | |
| 54 } | |
| 55 | |
| 56 void | |
| 57 arcfour_setkey (arcfour_context * context, const char *key, size_t keylen) | |
| 58 { | |
| 59 size_t i, j, k; | |
| 60 char *sbox = context->sbox; | |
| 61 | |
| 62 context->idx_i = context->idx_j = 0; | |
| 63 for (i = 0; i < ARCFOUR_SBOX_SIZE; i++) | |
| 64 sbox[i] = i; | |
| 65 for (i = j = k = 0; i < ARCFOUR_SBOX_SIZE; i++) | |
| 66 { | |
| 67 char t; | |
| 68 j = (j + sbox[i] + key[k]) % ARCFOUR_SBOX_SIZE; | |
| 69 t = sbox[i]; | |
| 70 sbox[i] = sbox[j]; | |
| 71 sbox[j] = t; | |
| 72 if (++k == keylen) | |
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12421
e8d2c6fc33ad
Use spaces for indentation, not tabs.
Bruno Haible <bruno@clisp.org>
parents:
7584
diff
changeset
|
73 k = 0; |
| 6377 | 74 } |
| 75 } |