Hi Dillon,
Thanks for the swift reply.
Regarding my code, I have a small utility that downloads an updated
database with information that I would like to encrypt. The method I
want to use if that the .exe would know how to decrypt the file and
display its data.
I'm really a newbie rookie novice here and just starting to get used
to the idea of composing multiple transformations on top one another.
Hugo's example looks very appealing to me and your touch of embedding
the key into the executable seems like exactly what I need.
After spending many hours following your last post, I reached the same
dead end... memcpy crashes.
Here's the detailed explanation:
I d/l the full dobrexor project, and since it didn't have a .dsp/.dsw
files set, I went and installed VS2005.
Since it didn't also have a .sln file, I realized the hard way that
the .vcproj file is of VS2008.
Nevermind, I created a new Win32 Console App. under VS2005 and since
then, I spent many hours trying to make everything work...
I used the statis lib. version of cryptopp552, which does not really
work out-of-the-box are requires its own tweaks.
It took me a while to realize that dobrexor is set to wirk with
cryptopp's DLL version.
I changed it to work with the static lib version, but I got into more
trouble when trying to use work with dobrexor's menus.
Trying to encrypt a file, it crashed with a null filename.
After a short while I found that dobrexor contains the following
lines:
const char pub[1024]="";
const char pri[4096]="";
Evidently, these supposed to be the pub/priv file names.
Added my own filename (although I think that dobrexor should ask the
user to input the pub/priv filenames, at least if the filename strings
are empty).
Now it all works, up to the point where I crash on the very same
memcpy line as stated above..........
I'm guessing you have a very well tweaked development environment, but
can you please verify and let me know if a clean copy of both dobrexor
and cryptopp552 compiles out-of-the-box (e.g. a clean install on a
VMWare or something)?
Thanks,
Avi.
On Feb 1, 2:24 pm, Dillon Beresford <[email protected]>
wrote:
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> Hash: SHA1
>
>
>
> Avi wrote:
> > Hi Dillon,
>
> > I'm new around here and new to the cryptography world.
>
> > I'm using VC++ 6.0 SP5 on a WinXP SP2 machine (I have a legacy code
> > base that I'd like to secure).
>
> > I tried to follow your (and originally Hugo's) example, but I'm having
> > the same runtime error in both cases.
> > I'm posting my problem here instead of in Hugo's thread in order to
> > narrow the differences between our executables (since you embedded
> > your keys into the source code).
>
> > The code crashes in oaep.cpp, line 91: memcpy(output, M, maskedDB
> > +dbLen-M);
> > The 'output' value is 0 (NULL).
>
> > I attached the call stack below.
> > Any ideas?
>
> > Avi.
>
> > --
> > CryptoPP::OAEP_Base::Unpad(const unsigned char * 0x0032b7f1, unsigned
> > int 255, unsigned char * 0x00000000, const CryptoPP::NameValuePairs &
> > {...}) line 91 + 20 bytes
> > CryptoPP::TF_DecryptorBase::Decrypt(CryptoPP::RandomNumberGenerator &
> > {...}, const unsigned char * 0x0032bbd8, unsigned int 257, unsigned
> > char * 0x00000000, const CryptoPP::NameValuePairs & {...}) line 142 +
> > 59 bytes
> > CryptoPP::PK_DefaultDecryptionFilter::Put2(const unsigned char *
> > 0x00000000, unsigned int 0, int -1, unsigned char 1) line 626 + 75
> > bytes
> > CryptoPP::BufferedTransformation::MessageEnd(int -1, unsigned char 1)
> > line 763 + 78 bytes
> > CryptoPP::SimpleProxyFilter::LastPut(const unsigned char * 0x00000000,
> > const unsigned char * 0x00000000) line 513 + 51 bytes
> > CryptoPP::FilterWithBufferedInput::PutMaybeModifiable(unsigned char *
> > 0x00326d68, unsigned int 0, int -2, unsigned char 1, unsigned char 0)
> > line 410
> > CryptoPP::FilterWithBufferedInput::Put2(const unsigned char *
> > 0x00326d68, unsigned int 0, int -2, unsigned char 1) line 156
> > CryptoPP::Filter::Output(int 2, const unsigned char * 0x00326d68,
> > unsigned int 0, int -2, unsigned char 1, const
> > std::basic_string<char,std::char_traits<char>,std::allocator<char> > &
> > {0x00000000 ""}) line 115 + 44 bytes
> > CryptoPP::BaseN_Decoder::Put2(const unsigned char * 0x00000000,
> > unsigned int 0, int -1, unsigned char 1) line 163 + 42 bytes
> > CryptoPP::BufferedTransformation::ChannelPut2(const
> > std::basic_string<char,std::char_traits<char>,std::allocator<char> > &
> > {0x00000000 ""}, const unsigned char * 0x00000000, unsigned int 0, int
> > -1, unsigned char 1) line 250 + 27 bytes
> > CryptoPP::BufferedTransformation::ChannelMessageEnd(const
> > std::basic_string<char,std::char_traits<char>,std::allocator<char> > &
> > {0x00000000 ""}, int -1, unsigned char 1) line 938 + 63 bytes
> > CryptoPP::BufferedTransformation::TransferMessagesTo2
> > (CryptoPP::BufferedTransformation & {...}, unsigned int & 0, const
> > std::basic_string<char,std::char_traits<char>,std::allocator<char> > &
> > {0x00000000 ""}, unsigned char 1) line 407 + 28 bytes
> > CryptoPP::BufferedTransformation::TransferAllTo2
> > (CryptoPP::BufferedTransformation & {...}, const
> > std::basic_string<char,std::char_traits<char>,std::allocator<char> > &
> > {0x00000000 ""}, unsigned char 1) line 448 + 24 bytes
> > CryptoPP::SourceTemplate<CryptoPP::StringStore>::PumpAll2(unsigned
> > char 1) line 718 + 73 bytes
> > CryptoPP::Source::PumpAll() line 689 + 47 bytes
> > CryptoPP::Source::SourceInitialize(unsigned char 1, const
> > CryptoPP::NameValuePairs & {...}) line 701
> > CryptoPP::StringSource::StringSource(const char * 0x0012fbd8, unsigned
> > char 1, CryptoPP::BufferedTransformation * 0x00326b10) line 737 + 173
> > bytes
> > stubClass::AES_CTR_Decrypt(const char * 0x0012ff48, const char *
> > 0x0012ff30) line 128 + 364 bytes
> > main() line 92
> > --
>
> > On Jan 23, 4:34 am, Dillon Beresford <[email protected]>
> > wrote:
> >> Hugo shared a class he coded up earlier this month which he gave to
>
> the group and while searching for information regarding an idea I came
> up with about self decrypting stubs using Crypto++, which I needed for
> my own project I found his thread. I was actually able to code up a
> little function which I added to the class to load keys using>>
> CryptoPP::ArraySource as opposed to LoadFile. For my project I needed
>
> to be able to generate stubs on the fly which would handle all of the
> decryption. I'm also currently writing up some code that will actually
> add two extra layers of protection to both keys inside the executable to
> avoid reverse code engineering from dumping keys in memory We simply
> store our keys in the stub.
>
> >> If we add stub + *.enc file to SFX we can have our stub do all the
> work for us. :)
>
> >> I would suggest to anyone storing keys inside a binary to compress the
>
> executable using something other than UPX or ASPack. ;-) keys get gen
> all the time so it's best to use something with tons of instructions for
> anti-debugging, strip TLS, exports, and CRC protection and aPlib for
> compression.
>
> >> Dillon's code reading from CryptoPP::ArraySource as opposed to
>
> CryptoPP::FileSource
>
>
>
> >> void stubClass::LoadKey(const char *bufferPub, const char *bufferPri) {
>
> >> CryptoPP::ArraySource(bufferPub, true,
>
> >> new CryptoPP::StringSink(pubString));
>
> >> CryptoPP::ArraySource(bufferPri, true,
>
> >> new CryptoPP::StringSink(priString));
>
> >> }
>
> >> Hugo's class using CryptoPP::FileSource
> >> /*
>
> >> void stubClass::LoadKey(const char *pubFilename, const char
> *privFilename) {
>
> >> CryptoPP::FileSource (pubFilename, true,
>
> >> new CryptoPP::StringSink(pubString));
>
> >> CryptoPP::FileSource (privFilename, true,
>
> >> new CryptoPP::StringSink(priString));
>
> >> }
>
> >> */
>
> >> We can store our keys in bufferPub and bufferPri and call this from
>
> the main() in our stub.
>
>
>
> >> const char bufferPri[]="308..."
> >> const char bufferPub[]="308..."
>
> >> int main() {
> >> char EFile[]="dob.enc";
> >> char DFile[]="dec.exe";
>
> >> stubClass stubDecrypt;
> >> // grab our keys from memory.
> >> stubDecrypt.LoadKey(bufferPub,bufferPri);
> >> // decrypt our file
> >> stubDecrypt.AES_CTR_Decrypt(EFile, DFile);
>
> >> return 0;
>
> >> }
>
> >> thanks Hugo!
>
> >> linked back to the original thread where Hugo posted his class.
>
> >>http://groups.google.com/group/cryptopp-users/browse_thread/thread/48...
>
> >> regards,
>
> >> Dillon Beresford
>
> >> stub.cpp
> >> 4KViewDownload
>
> >> stubClass.cpp
> >> 3KViewDownload
>
> >> stubClass.h
> >> < 1KViewDownload
>
> Avi - It looks like it's the first argument in memcpy(), if it's
> output is NULL then you get the error. Are you planning on decrypting
> from a stub or just need the decryption and encryption to read from
> key files? If you take a look at the svn Hugo and I maintain for our
> project you might get a better working example of how the Class is
> implemented. You can download the project here and use dobclass.
>
> http://code.google.com/p/komodopgmp/source/browse/trunk/windows/dev/d...http://code.google.com/p/komodopgmp/source/browse/trunk/windows/dev/d...
>
> Download the entire project if you like. It's the full implementation
> of the class you want.
>
> http://komodopgmp.googlecode.com/files/dobrexor-beta-build-win-curren...
>
> // file.read(Key,512); <--
>
> Let me know how your LoadKeys is working. Are you planning on securing
> this legacy code from one application or working with a self
> decrypting archive?
>
> Regards,
>
> Dillon Beresford
> Komodo PGMP projecthttp://code.google.com/p/komodopgmp/
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> pgpkeys.asc
> 2KViewDownload
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