linux-imx

/*

 * Cryptographic API

 *

 * ARC4 Cipher Algorithm

 *

 * Jon Oberheide <jon@oberheide.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 */

​

#include <crypto/algapi.h>

#include <crypto/arc4.h>

#include <crypto/internal/skcipher.h>

#include <linux/init.h>

#include <linux/module.h>

​

struct arc4_ctx {

    u32 S[256];

    u32 x, y;

};

​

static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,

            unsigned int key_len)

{

    struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);

    int i, j = 0, k = 0;

​

    ctx->x = 1;

    ctx->y = 0;

​

    for (i = 0; i < 256; i++)

        ctx->S[i] = i;

​

    for (i = 0; i < 256; i++) {

        u32 a = ctx->S[i];

        j = (j + in_key[k] + a) & 0xff;

        ctx->S[i] = ctx->S[j];

        ctx->S[j] = a;

        if (++k >= key_len)

            k = 0;

    }

​

    return 0;

}

​

static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,

                 unsigned int key_len)

{

    return arc4_set_key(&tfm->base, in_key, key_len);

}

​

static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,

               unsigned int len)

{

    u32 *const S = ctx->S;

    u32 x, y, a, b;

    u32 ty, ta, tb;

​

    if (len == 0)