AES encryption problem

[elippo]

Hello,

I am facing a problem using the AES decryption that I got from link
My function exits and doesn't continue the algorithm after the execution of the following line of code

bufDecryptor->ProcessFinalL(plainTextPtr,cipherTextPtr);

I have surfed the web, and I've found several issues with same problem without any solution.
So can anyone help me with this issue ?
Kindly find below the function I am using for decryption.

QString MainWindow::decryptData(QString dataToDecrypt,QString keyOfDecryption)
{
    TPtrC16 textPtr1(reinterpret_cast<const TUint16*>(keyOfDecryption.utf16()));
    HBufC8 *pHeap81 = HBufC8::NewMaxLC(textPtr1.Length());
    pHeap81->Des().Copy(textPtr1);
    TPtr8 aKey = pHeap81->Des();
    TPtr8 aIv = pHeap81->Des();
    QString enc(QByteArray::fromBase64(dataToDecrypt.toAscii()));
    RFs fsSession;
    User::LeaveIfError(fsSession.Connect());
    TPtrC16 textPtr(reinterpret_cast<const TUint16*>(enc.utf16()));
    HBufC8 *pHeap8 = HBufC8::NewMaxLC(textPtr.Length());
    pHeap8->Des().Copy(textPtr);
    TPtr8 plainTextPtr = pHeap8->Des();
    CAESDecryptor* method = CAESDecryptor::NewL(aKey);
    CModeCBCDecryptor* mode = CModeCBCDecryptor::NewL(method, aIv);
    CPadding* padding = CPaddingPKCS7::NewL(method->BlockSize());
    CBufferedDecryptor* bufDecryptor = CBufferedDecryptor::NewL(mode, padding);
    HBufC8* cipherText = HBufC8::NewL(bufDecryptor->MaxFinalOutputLength(plainTextPtr.Size()));
    TPtr8 cipherTextPtr = cipherText->Des();
    bufDecryptor->ProcessFinalL(plainTextPtr,cipherTextPtr);
    QString result3;
    result3=QString::fromAscii((const char *)cipherText->Ptr(), cipherText->Length());
    CleanupStack::PopAndDestroy();
    CleanupStack::PopAndDestroy();
    return result3;
}

Note that there is something so weird about it; Sometimes I am able to decrypt some encrypted data with the same algorithm,and sometimes it fails for another encrypted data.

Best Regards,
elippo

[symbianyucca]

Might help if you get the panic/leave code, it might give good ideas on what is going wrong in there.

[elippo]

Might help if you get the panic/leave code, it might give good ideas on what is going wrong in there.

I got on my debug screen

Active object (ptr=0x00903648, vptr=0x7d944a8c) leave: -6

and using Y-task I got the following error ( JavaCommsClient-10000-0x13075fd0-621051169 Kill : 4320892 )

Any idea ?

[symbianyucca]

-6 if that is really error code, would indicate bad request: http://www.developer.nokia.com/Commu...OS_Error_Codes , so you should check what kind of values you are supposed to give to the function

[elippo]

Does anyone have an idea why the decryptData function works for some strings, and fails on others.

Best Regards

[symbianyucca]

Not certain if it helps, but can you check whether it is related to the code string lenght ? or any other issue which would make the string different.

The paddign there should take care of the right sizing, anyway, can you check that cipherText really is 16-bytes dividable, and not 8 bytes in all cases..

[elippo]

HI,

I have noticed the below.
Crashing String: . "QStrig dataToDecrypt" passed to the function have a size of "44"
. " TPtr8 plainTextPtr " have a size of "5"
. " TPtr8 cipherTextPtr" have a size of "0"

Working Sring : . "QStrig dataToDecrypt" passed to the function have a size of "44"
. " TPtr8 plainTextPtr " have a size of "32"
. " TPtr8 cipherTextPtr" have a size of "27"

So the problem is in the plainTextPtr. why the size is "5" ?????

QString enc(QByteArray::fromBase64(dataToDecrypt.toAscii()));
RFs fsSession;
User::LeaveIfError(fsSession.Connect());
TPtrC16 textPtr(reinterpret_cast<const TUint16*>(enc.utf16()));
HBufC8 *pHeap8 = HBufC8::NewMaxLC(textPtr.Length());
pHeap8->Des().Copy(textPtr);
TPtr8 plainTextPtr = pHeap8->Des(); // [B]plainTextPtr.Size() is equals sometimes to 32(decryption work well) and sometime to 5 (decryption crash).[/B]

Any Help ? Please I need to fix this problem of decryption.