| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. |
| 3 | * |
| 4 | * Licensed under the OpenSSL license (the "License"). You may not use |
| 5 | * this file except in compliance with the License. You can obtain a copy |
| 6 | * in the file LICENSE in the source distribution or at |
| 7 | * https://www.openssl.org/source/license.html |
| 8 | */ |
| 9 | |
| 10 | #include <openssl/rc4.h> |
| 11 | #include "rc4_local.h" |
| 12 | |
| 13 | /*- |
| 14 | * RC4 as implemented from a posting from |
| 15 | * Newsgroups: sci.crypt |
| 16 | * Subject: RC4 Algorithm revealed. |
| 17 | * Message-ID: <sternCvKL4B.Hyy@netcom.com> |
| 18 | * Date: Wed, 14 Sep 1994 06:35:31 GMT |
| 19 | */ |
| 20 | |
| 21 | void RC4(RC4_KEY *key, size_t len, const unsigned char *indata, |
| 22 | unsigned char *outdata) |
| 23 | { |
| 24 | register RC4_INT *d; |
| 25 | register RC4_INT x, y, tx, ty; |
| 26 | size_t i; |
| 27 | |
| 28 | x = key->x; |
| 29 | y = key->y; |
| 30 | d = key->data; |
| 31 | |
| 32 | #define LOOP(in,out) \ |
| 33 | x=((x+1)&0xff); \ |
| 34 | tx=d[x]; \ |
| 35 | y=(tx+y)&0xff; \ |
| 36 | d[x]=ty=d[y]; \ |
| 37 | d[y]=tx; \ |
| 38 | (out) = d[(tx+ty)&0xff]^ (in); |
| 39 | |
| 40 | i = len >> 3; |
| 41 | if (i) { |
| 42 | for (;;) { |
| 43 | LOOP(indata[0], outdata[0]); |
| 44 | LOOP(indata[1], outdata[1]); |
| 45 | LOOP(indata[2], outdata[2]); |
| 46 | LOOP(indata[3], outdata[3]); |
| 47 | LOOP(indata[4], outdata[4]); |
| 48 | LOOP(indata[5], outdata[5]); |
| 49 | LOOP(indata[6], outdata[6]); |
| 50 | LOOP(indata[7], outdata[7]); |
| 51 | indata += 8; |
| 52 | outdata += 8; |
| 53 | if (--i == 0) |
| 54 | break; |
| 55 | } |
| 56 | } |
| 57 | i = len & 0x07; |
| 58 | if (i) { |
| 59 | for (;;) { |
| 60 | LOOP(indata[0], outdata[0]); |
| 61 | if (--i == 0) |
| 62 | break; |
| 63 | LOOP(indata[1], outdata[1]); |
| 64 | if (--i == 0) |
| 65 | break; |
| 66 | LOOP(indata[2], outdata[2]); |
| 67 | if (--i == 0) |
| 68 | break; |
| 69 | LOOP(indata[3], outdata[3]); |
| 70 | if (--i == 0) |
| 71 | break; |
| 72 | LOOP(indata[4], outdata[4]); |
| 73 | if (--i == 0) |
| 74 | break; |
| 75 | LOOP(indata[5], outdata[5]); |
| 76 | if (--i == 0) |
| 77 | break; |
| 78 | LOOP(indata[6], outdata[6]); |
| 79 | if (--i == 0) |
| 80 | break; |
| 81 | } |
| 82 | } |
| 83 | key->x = x; |
| 84 | key->y = y; |
| 85 | } |