/* * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (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 */ #include <openssl/rc4.h> #include "rc4_locl.h" /*- * RC4 as implemented from a posting from * Newsgroups: sci.crypt * From: sterndark@netcom.com (David Sterndark) * Subject: RC4 Algorithm revealed. * Message-ID: <sternCvKL4B.Hyy@netcom.com> * Date: Wed, 14 Sep 1994 06:35:31 GMT */ void RC4(RC4_KEY *key, size_t len, const unsigned char *indata, unsigned char *outdata) { register RC4_INT *d; register RC4_INT x, y, tx, ty; size_t i; x = key->x; y = key->y; d = key->data; #define LOOP(in,out) \ x=((x+1)&0xff); \ tx=d[x]; \ y=(tx+y)&0xff; \ d[x]=ty=d[y]; \ d[y]=tx; \ (out) = d[(tx+ty)&0xff]^ (in); i = len >> 3; if (i) { for (;;) { LOOP(indata[0], outdata[0]); LOOP(indata[1], outdata[1]); LOOP(indata[2], outdata[2]); LOOP(indata[3], outdata[3]); LOOP(indata[4], outdata[4]); LOOP(indata[5], outdata[5]); LOOP(indata[6], outdata[6]); LOOP(indata[7], outdata[7]); indata += 8; outdata += 8; if (--i == 0) break; } } i = len & 0x07; if (i) { for (;;) { LOOP(indata[0], outdata[0]); if (--i == 0) break; LOOP(indata[1], outdata[1]); if (--i == 0) break; LOOP(indata[2], outdata[2]); if (--i == 0) break; LOOP(indata[3], outdata[3]); if (--i == 0) break; LOOP(indata[4], outdata[4]); if (--i == 0) break; LOOP(indata[5], outdata[5]); if (--i == 0) break; LOOP(indata[6], outdata[6]); if (--i == 0) break; } } key->x = x; key->y = y; }