ia64/linux-2.6.18-xen.hg

view crypto/arc4.c @ 854:950b9eb27661

usbback: fix urb interval value for interrupt urbs.

Signed-off-by: Noboru Iwamatsu <n_iwamatsu@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Apr 06 13:51:20 2009 +0100 (2009-04-06)
parents 831230e53067
children
line source
1 /*
2 * Cryptographic API
3 *
4 * ARC4 Cipher Algorithm
5 *
6 * Jon Oberheide <jon@oberheide.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 */
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/crypto.h>
18 #define ARC4_MIN_KEY_SIZE 1
19 #define ARC4_MAX_KEY_SIZE 256
20 #define ARC4_BLOCK_SIZE 1
22 struct arc4_ctx {
23 u8 S[256];
24 u8 x, y;
25 };
27 static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
28 unsigned int key_len, u32 *flags)
29 {
30 struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
31 int i, j = 0, k = 0;
33 ctx->x = 1;
34 ctx->y = 0;
36 for(i = 0; i < 256; i++)
37 ctx->S[i] = i;
39 for(i = 0; i < 256; i++)
40 {
41 u8 a = ctx->S[i];
42 j = (j + in_key[k] + a) & 0xff;
43 ctx->S[i] = ctx->S[j];
44 ctx->S[j] = a;
45 if(++k >= key_len)
46 k = 0;
47 }
49 return 0;
50 }
52 static void arc4_crypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
53 {
54 struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
56 u8 *const S = ctx->S;
57 u8 x = ctx->x;
58 u8 y = ctx->y;
59 u8 a, b;
61 a = S[x];
62 y = (y + a) & 0xff;
63 b = S[y];
64 S[x] = b;
65 S[y] = a;
66 x = (x + 1) & 0xff;
67 *out++ = *in ^ S[(a + b) & 0xff];
69 ctx->x = x;
70 ctx->y = y;
71 }
73 static struct crypto_alg arc4_alg = {
74 .cra_name = "arc4",
75 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
76 .cra_blocksize = ARC4_BLOCK_SIZE,
77 .cra_ctxsize = sizeof(struct arc4_ctx),
78 .cra_module = THIS_MODULE,
79 .cra_list = LIST_HEAD_INIT(arc4_alg.cra_list),
80 .cra_u = { .cipher = {
81 .cia_min_keysize = ARC4_MIN_KEY_SIZE,
82 .cia_max_keysize = ARC4_MAX_KEY_SIZE,
83 .cia_setkey = arc4_set_key,
84 .cia_encrypt = arc4_crypt,
85 .cia_decrypt = arc4_crypt } }
86 };
88 static int __init arc4_init(void)
89 {
90 return crypto_register_alg(&arc4_alg);
91 }
94 static void __exit arc4_exit(void)
95 {
96 crypto_unregister_alg(&arc4_alg);
97 }
99 module_init(arc4_init);
100 module_exit(arc4_exit);
102 MODULE_LICENSE("GPL");
103 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
104 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");