2 * Copyright 2006 Mike McCormack
4 * based on arc4.cpp - written and placed in the public domain by Wei Dai
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 /* http://cryptopp.sourceforge.net/docs/ref521/arc4_8cpp-source.html */
26 #define WIN32_NO_STATUS
30 typedef struct tag_arc4_info {
31 unsigned char state[256];
35 static void arc4_init(arc4_info *a4i, const BYTE *key, unsigned int keyLen)
37 unsigned int keyIndex = 0, stateIndex = 0;
48 stateIndex += key[keyIndex] + a;
50 a4i->state[i] = a4i->state[stateIndex];
51 a4i->state[stateIndex] = a;
52 if (++keyIndex >= keyLen)
57 static void arc4_ProcessString(arc4_info *a4i, BYTE *inoutString, unsigned int length)
59 BYTE *const s=a4i->state;
60 unsigned int x = a4i->x;
61 unsigned int y = a4i->y;
72 *inoutString++ ^= s[(a+b) & 0xff];
82 unsigned char *Buffer;
85 /******************************************************************************
86 * SystemFunction032 [ADVAPI32.@]
88 * Encrypts a string data using ARC4
91 * data [I/O] data to encrypt
95 * Success: STATUS_SUCCESS
96 * Failure: STATUS_UNSUCCESSFUL
99 * see http://web.it.kth.se/~rom/ntsec.html#crypto-strongavail
101 NTSTATUS WINAPI SystemFunction032(struct ustring *data, struct ustring *key)
105 arc4_init(&a4i, key->Buffer, key->Length);
106 arc4_ProcessString(&a4i, data->Buffer, key->Length);
108 return STATUS_SUCCESS;