/*

 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

/*

 * RC4 low level APIs are deprecated for public use, but still ok for internal

 * use.

 */

#include "internal/deprecated.h"

#include <openssl/rc4.h>

#include "rc4_local.h"

#include <openssl/opensslv.h>

const char *RC4_options(void)

{

    if (sizeof(RC4_INT) == 1)

        return "rc4(char)";

    else

        return "rc4(int)";

}

/*-

 * RC4 as implemented from a posting from

 * Newsgroups: sci.crypt

 * Subject: RC4 Algorithm revealed.

 * Message-ID: <sternCvKL4B.Hyy@netcom.com>

 * Date: Wed, 14 Sep 1994 06:35:31 GMT

 */

void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)

{

    register RC4_INT tmp;

    register int id1, id2;

    register RC4_INT *d;

    unsigned int i;

    d = &(key->data[0]);

    key->x = 0;

    key->y = 0;

    id1 = id2 = 0;

#define SK_LOOP(d,n) { \

                tmp=d[(n)]; \

                id2 = (data[id1] + tmp + id2) & 0xff; \

                if (++id1 == len) id1=0; \

                d[(n)]=d[id2]; \

                d[id2]=tmp; }

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

        d[i] = i;

    for (i = 0; i < 256; i += 4) {

        SK_LOOP(d, i + 0);

        SK_LOOP(d, i + 1);

        SK_LOOP(d, i + 2);

        SK_LOOP(d, i + 3);

    }

}