/* * Copyright 2006 Mike McCormack * * based on arc4.cpp - written and placed in the public domain by Wei Dai * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA */ /* http://cryptopp.sourceforge.net/docs/ref521/arc4_8cpp-source.html */ #include <stdarg.h> #include "ntstatus.h" #define WIN32_NO_STATUS #include "windef.h" #include "winternl.h" #include "crypt.h" typedef struct tag_arc4_info { unsigned char state[256]; unsigned char x, y; } arc4_info; static void arc4_init(arc4_info *a4i, const BYTE *key, unsigned int keyLen) { unsigned int keyIndex = 0, stateIndex = 0; unsigned int i, a; a4i->x = a4i->y = 0; for (i=0; i<256; i++) a4i->state[i] = i; for (i=0; i<256; i++) { a = a4i->state[i]; stateIndex += key[keyIndex] + a; stateIndex &= 0xff; a4i->state[i] = a4i->state[stateIndex]; a4i->state[stateIndex] = a; if (++keyIndex >= keyLen) keyIndex = 0; } } static void arc4_ProcessString(arc4_info *a4i, BYTE *inoutString, unsigned int length) { BYTE *const s=a4i->state; unsigned int x = a4i->x; unsigned int y = a4i->y; unsigned int a, b; while(length--) { x = (x+1) & 0xff; a = s[x]; y = (y+a) & 0xff; b = s[y]; s[x] = b; s[y] = a; *inoutString++ ^= s[(a+b) & 0xff]; } a4i->x = x; a4i->y = y; } /****************************************************************************** * SystemFunction032 [ADVAPI32.@] * * Encrypts a string data using ARC4 * * PARAMS * data [I/O] data to encrypt * key [I] key data * * RETURNS * Success: STATUS_SUCCESS * Failure: STATUS_UNSUCCESSFUL * * NOTES * see http://web.it.kth.se/~rom/ntsec.html#crypto-strongavail */ NTSTATUS WINAPI SystemFunction032(struct ustring *data, const struct ustring *key) { arc4_info a4i; arc4_init(&a4i, key->Buffer, key->Length); arc4_ProcessString(&a4i, data->Buffer, data->Length); return STATUS_SUCCESS; }