/*
 * 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);
    }
}