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// Crypto/WzAes.cpp
/*
This code implements Brian Gladman's scheme
specified in password Based File Encryption Utility.
Note: you must include MyAes.cpp to project to initialize AES tables
*/
#include "StdAfx.h"
#include "../Common/StreamObjects.h"
#include "../Common/StreamUtils.h"
#include "Pbkdf2HmacSha1.h"
#include "RandGen.h"
#include "WzAes.h"
// define it if you don't want to use speed-optimized version of Pbkdf2HmacSha1
// #define _NO_WZAES_OPTIMIZATIONS
namespace NCrypto {
namespace NWzAes {
const unsigned kAesKeySizeMax = 32;
static const UInt32 kNumKeyGenIterations = 1000;
STDMETHODIMP CBaseCoder::CryptoSetPassword(const Byte *data, UInt32 size)
{
if(size > kPasswordSizeMax)
return E_INVALIDARG;
_key.Password.SetCapacity(size);
memcpy(_key.Password, data, size);
return S_OK;
}
#ifndef _NO_WZAES_OPTIMIZATIONS
static void BytesToBeUInt32s(const Byte *src, UInt32 *dest, unsigned destSize)
{
for (unsigned i = 0; i < destSize; i++)
dest[i] =
((UInt32)(src[i * 4 + 0]) << 24) |
((UInt32)(src[i * 4 + 1]) << 16) |
((UInt32)(src[i * 4 + 2]) << 8) |
((UInt32)(src[i * 4 + 3]));
}
#endif
STDMETHODIMP CBaseCoder::Init()
{
UInt32 keySize = _key.GetKeySize();
UInt32 keysTotalSize = 2 * keySize + kPwdVerifCodeSize;
Byte buf[2 * kAesKeySizeMax + kPwdVerifCodeSize];
// for (unsigned ii = 0; ii < 1000; ii++)
{
#ifdef _NO_WZAES_OPTIMIZATIONS
NSha1::Pbkdf2Hmac(
_key.Password, _key.Password.GetCapacity(),
_key.Salt, _key.GetSaltSize(),
kNumKeyGenIterations,
buf, keysTotalSize);
#else
UInt32 buf32[(2 * kAesKeySizeMax + kPwdVerifCodeSize + 3) / 4];
UInt32 key32SizeTotal = (keysTotalSize + 3) / 4;
UInt32 salt[kSaltSizeMax * 4];
UInt32 saltSizeInWords = _key.GetSaltSize() / 4;
BytesToBeUInt32s(_key.Salt, salt, saltSizeInWords);
NSha1::Pbkdf2Hmac32(
_key.Password, _key.Password.GetCapacity(),
salt, saltSizeInWords,
kNumKeyGenIterations,
buf32, key32SizeTotal);
for (UInt32 j = 0; j < keysTotalSize; j++)
buf[j] = (Byte)(buf32[j / 4] >> (24 - 8 * (j & 3)));
#endif
}
_hmac.SetKey(buf + keySize, keySize);
memcpy(_key.PwdVerifComputed, buf + 2 * keySize, kPwdVerifCodeSize);
AesCtr2_Init(&_aes);
Aes_SetKey_Enc(_aes.aes + _aes.offset + 8, buf, keySize);
return S_OK;
}
HRESULT CEncoder::WriteHeader(ISequentialOutStream *outStream)
{
UInt32 saltSize = _key.GetSaltSize();
g_RandomGenerator.Generate(_key.Salt, saltSize);
Init();
RINOK(WriteStream(outStream, _key.Salt, saltSize));
return WriteStream(outStream, _key.PwdVerifComputed, kPwdVerifCodeSize);
}
HRESULT CEncoder::WriteFooter(ISequentialOutStream *outStream)
{
Byte mac[kMacSize];
_hmac.Final(mac, kMacSize);
return WriteStream(outStream, mac, kMacSize);
}
STDMETHODIMP CDecoder::SetDecoderProperties2(const Byte *data, UInt32 size)
{
if (size != 1)
return E_INVALIDARG;
_key.Init();
return SetKeyMode(data[0]) ? S_OK : E_INVALIDARG;
}
HRESULT CDecoder::ReadHeader(ISequentialInStream *inStream)
{
UInt32 saltSize = _key.GetSaltSize();
UInt32 extraSize = saltSize + kPwdVerifCodeSize;
Byte temp[kSaltSizeMax + kPwdVerifCodeSize];
RINOK(ReadStream_FAIL(inStream, temp, extraSize));
UInt32 i;
for (i = 0; i < saltSize; i++)
_key.Salt[i] = temp[i];
for (i = 0; i < kPwdVerifCodeSize; i++)
_pwdVerifFromArchive[i] = temp[saltSize + i];
return S_OK;
}
static bool CompareArrays(const Byte *p1, const Byte *p2, UInt32 size)
{
for (UInt32 i = 0; i < size; i++)
if (p1[i] != p2[i])
return false;
return true;
}
bool CDecoder::CheckPasswordVerifyCode()
{
return CompareArrays(_key.PwdVerifComputed, _pwdVerifFromArchive, kPwdVerifCodeSize);
}
HRESULT CDecoder::CheckMac(ISequentialInStream *inStream, bool &isOK)
{
isOK = false;
Byte mac1[kMacSize];
RINOK(ReadStream_FAIL(inStream, mac1, kMacSize));
Byte mac2[kMacSize];
_hmac.Final(mac2, kMacSize);
isOK = CompareArrays(mac1, mac2, kMacSize);
return S_OK;
}
CAesCtr2::CAesCtr2()
{
offset = ((0 - (unsigned)(ptrdiff_t)aes) & 0xF) / sizeof(UInt32);
}
void AesCtr2_Init(CAesCtr2 *p)
{
UInt32 *ctr = p->aes + p->offset + 4;
unsigned i;
for (i = 0; i < 4; i++)
ctr[i] = 0;
p->pos = AES_BLOCK_SIZE;
}
void AesCtr2_Code(CAesCtr2 *p, Byte *data, SizeT size)
{
unsigned pos = p->pos;
UInt32 *buf32 = p->aes + p->offset;
if (size == 0)
return;
if (pos != AES_BLOCK_SIZE)
{
const Byte *buf = (const Byte *)buf32;
do
*data++ ^= buf[pos++];
while (--size != 0 && pos != AES_BLOCK_SIZE);
}
if (size >= 16)
{
SizeT size2 = size >> 4;
g_AesCtr_Code(buf32 + 4, data, size2);
size2 <<= 4;
data += size2;
size -= size2;
pos = AES_BLOCK_SIZE;
}
if (size != 0)
{
unsigned j;
const Byte *buf;
for (j = 0; j < 4; j++)
buf32[j] = 0;
g_AesCtr_Code(buf32 + 4, (Byte *)buf32, 1);
buf = (const Byte *)buf32;
pos = 0;
do
*data++ ^= buf[pos++];
while (--size != 0 && pos != AES_BLOCK_SIZE);
}
p->pos = pos;
}
STDMETHODIMP_(UInt32) CEncoder::Filter(Byte *data, UInt32 size)
{
AesCtr2_Code(&_aes, data, size);
_hmac.Update(data, size);
return size;
}
STDMETHODIMP_(UInt32) CDecoder::Filter(Byte *data, UInt32 size)
{
_hmac.Update(data, size);
AesCtr2_Code(&_aes, data, size);
return size;
}
}}
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