Re: Debug/Release problems (again) CryptLib v4.2

[Michael Hunley]

I haven't used the RijndaelEncryption class, yet, but chances are it uses 
some form of randomness to improve the cryptographic security.  It 
generally is not correct to "validate" a crypto algorithm by comparing the 
output of two encryptions.  The validation is to encrypt and decrypt and 
make sure the plaintext matches (checksums aren't a bad idea, either).  Is 
this what you have done, or are you doing a byte compare on the output of rEnc?

At 07:24 PM 4/8/2003 +0530, you wrote:
Hi,

I've got terrible problems with cryptlib.
I have two seperate applications, one is a general purpose key generator 
and the other is an application that uses cryptlib.
After some trouble I managed to get the keygen to puke out the same output 
given an input and vice versa.
I did the same to the application.

Now the trouble is when I use the output from the keygen as an input to 
the application, it doesn't give me the correct result.

Here's what the code looks like:

bool Obfuscate(char * szSrc, BYTE * sEncrypted, int * iBufferSize)
{
try {
    CryptoPP::RijndaelEncryption rEnc(ENCRYPTIONKEY);
    memset(sEncrypted, 0, *iBufferSize);
    int iSize = strlen(szSrc);
    if(iSize > *iBufferSize)
    {
        return false;
    }
    if(iSize < *iBufferSize && (*iBufferSize - iSize - 1) > 0)
        memset(&szSrc[iSize], 0, *iBufferSize - iSize - 1); // ensure 
rest of array is empty
    // compute no of 16 byte blocks
    int nBlocks;
    if(iSize % 16 == 0)
        nBlocks = iSize/16;
    else
        nBlocks = iSize/16 + 1; // last block will be padded with 0s

    for(int i = 0; i < nBlocks; i++)
    {
        rEnc.ProcessBlock((BYTE *)&szSrc[i*16], (BYTE *)&sEncrypted[i*16]);
    }
    *iBufferSize = nBlocks * 16;
}
catch(CryptoPP::Exception &e)
{
return false;
}
catch(std::exception &e)
{
return false;
}
catch(...)
{
return false;
}
return true;
}
Now, what is the problem??

Why should two different programs including the _same_copy_ of the library 
be unable to yield the same result?
The only difference is that one of the apps uses the above code as a 
member function (of a class) and the other uses it as a raw function (no 
class).

I picture myself as going bald trying to solve the problem... and I'm only 
25!! :)
I can provide the project settings if required, but they're absolutely the 
same.