prng.cpp
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/* Copyright (C) 2010-2012 kaosu (qiupf2000@gmail.com)
* This file is part of the Interactive Text Hooker.
* Interactive Text Hooker is free software: you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* This program 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 General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "aes256.h"
#include "prng.h"
//#include "sha.h"
#include <ITH\Hash.h>
void PRNGInit(PRNGContext* ctx)
{
unsigned int seed;
__asm rdtsc
__asm mov seed,eax
HashSHA256((u8*)&seed, 4, ctx->prng_key);
memset(ctx->prng_key + 32,0,224);
KeyExpansion(ctx->prng_key);
}
void PRNGGen(PRNGContext* ctx, unsigned char *dest, unsigned int size)
{
unsigned int i,remain;
if (size<=0) return;
memset(dest,0,size);
remain=size&0xF;
size &= ~0xF;
for (i=0;i<size;i+=0x10)
{
AES256EncryptRound(ctx->seed,ctx->seed,ctx->prng_key,4);
memcpy(dest+i,ctx->seed, 0x10);
//memcpy(dest+(i<<4),ctx->seed,0x10);
}
if (remain)
{
AES256EncryptRound(ctx->seed,ctx->seed,ctx->prng_key,4);
memcpy(dest+size,ctx->seed,remain);
}
}