LockBox3 DecryptStream can't create plain stream

Question

When I try to encode some binary data everything works fine:

void __fastcall TForm1::EncryptBtnClick(TObject *Sender)
{
  char plainchar[16]={0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F};
  char keychar[16]={0xE8,0xE9,0xEA,0xEB,0xED,0xEE,0xEF,0xF0,0xF2,0xF3,0xF4,0xF5,0xF7,0xF8,0xF9,0xFA};
  char chiperchar[16];

  TMemoryStream *plainStream;
  TMemoryStream *chiperStream;
  TMemoryStream *keyStream;

  plainStream = new TMemoryStream();
  chiperStream = new TMemoryStream();
  keyStream = new TMemoryStream();

  plainStream->Clear();
  plainStream->Position=0;
  plainStream->WriteBuffer(plainchar,16);
  plainStream->Position=0;

  keyStream->Clear();
  keyStream->Position=0;
  keyStream->WriteBuffer(keychar,16);
  keyStream->Position=0;
  Codec1->Reset();
  Codec1->InitFromStream(keyStream);

  Codec1->EncryptStream(plainStream,chiperStream);

  chiperStream->Position=0;
  chiperStream->ReadBuffer(chiperchar,16);

  plainStream->Free();
  chiperStream->Free();
  keyStream->Free();
}

And I get expected

0x3E,0x45,0xC2,0x15,0xBA,0x45,0x0E,0xA6,0xEF,0x94,0xA3,0x08,0x82,0xB8,0x1B,0xD4

in chiperchar buffer.

Unfortunately when I try to use DecryptStream function for above chiper buffer, it doesn't create plain data stream (stream is 0 byte lenght)

void __fastcall TForm1::DecryptBtnClick(TObject *Sender)
{
char chiperchar[16]={0x3E,0x45,0xC2,0x15,0xBA,0x45,0x0E,0xA6,0xEF,0x94,0xA3,0x08,0x82,0xB8,0x1B,0xD4};
char keychar[16]={0xE8,0xE9,0xEA,0xEB,0xED,0xEE,0xEF,0xF0,0xF2,0xF3,0xF4,0xF5,0xF7,0xF8,0xF9,0xFA};
char plainchar[16];

TMemoryStream *plainStream;
TMemoryStream *chiperStream;
TMemoryStream *keyStream;

plainStream = new TMemoryStream();
chiperStream = new TMemoryStream();
keyStream = new TMemoryStream();

chiperStream->Clear();
chiperStream->Position=0;
chiperStream->WriteBuffer(chiperchar,16);
chiperStream->Position=0;

keyStream->Clear();
keyStream->Position=0;
keyStream->WriteBuffer(keychar,16);
keyStream->Position=0;
Codec1->Reset();
Codec1->InitFromStream(keyStream);

plainStream->Clear();
plainStream->Position=0;

Codec1->DecryptStream(plainStream,chiperStream);

plainStream->Position=0;
chiperStream->Position=0;

plainStream->Position=0;
plainStream->ReadBuffer(plainchar,16);

plainStream->Free();
chiperStream->Free();
keyStream->Free();
}

What I'm dooing wrong ? Why DecrpytStream cannot create proper stream ?

When I use EncryptString and DecryptString functions, everything works fine, and after encryption and decryption I get the same string.

Codec1 properties are:

AsymetricKeySizeInBits = 128
AdvancedOptions2 = []
CryptoLibrary = CryptographicLibrary1
StreamCipherId = 'native.StreamToBlock'
BlockCipherId = 'native.AES-128'
ChainId = 'native.ECB'

Lockbox is a Delphi cryptographic library. What language is this? Java? C++? What version of Lockbox are you using and where did you source it from? — Sean B. Durkin, Jul 04 '16 at 23:59
This is C++ Builder 10 Seattle from Embarcadero, LockBox version 3.5.0 has been sourced from GetIt Package Manager build in IDE. I've tried use DecryptStream and DecryptMemory functions. In both cases function doesn't fill plainStream (plainStream->Lenght is still 0). EncryptStream function works fine, as well as EncryptString and DecryptString. Can you please provide any working demo code for C++ or Delphi ? — Sebastor, Jul 05 '16 at 05:56
After instalation I had to comment this line" __property TOnGenerateKeyFunc OnCustomCipherGenerateKey = {read=FOnGenerateKeyFunc, write=FOnGenerateKeyFunc};" in Utplb_cryptographiclibrary.hpp file. Could this be the caouse of these problem ? — Sebastor, Jul 05 '16 at 11:01

score 0 · Answer 1 · answered Jul 06 '16 at 07:39

Sorry, I don't know C++. My language is Delphi.

This works ....

procedure TForm30.Button1Click(Sender: TObject);
const
  chiperchar: utf8string = #$3E#$45#$C2#$15#$BA#$45#$0E#$A6#$EF#$94#$A3#$08#$82#$B8#$1B#$D4;
  keychar   : utf8string = #$E8#$E9#$EA#$EB#$ED#$EE#$EF#$F0#$F2#$F3#$F4#$F5#$F7#$F8#$F9#$FA;
var
  plainStream, chiperStream, keyStream: TMemoryStream;
  OriginalPlainText: string;
  ReconstructedPlainText: string;

begin
  plainStream  := TMemoryStream.Create;
  chiperStream := TMemoryStream.Create;
  keyStream    := TMemoryStream.Create;
  try
    OriginalPlainText := 'Your lips are smoother than vasoline.';
    Memo1.Lines.Add( 'Plaintext (passed as UTF-8 encoding) = "' + OriginalPlainText + '"');
    TPLB3.StreamUtils.String_to_stream( OriginalPlainText, plainStream, TEncoding.UTF8);
    Memo1.Lines.Add( 'Length of plaintext = ' + IntToStr( plainStream.Size) + ' bytes.');
    keyStream.WriteBuffer( keychar[ Low( keychar)], Length( keychar));
    keyStream.Position := 0;
    Codec1.InitFromStream( keyStream);

    Codec1.EncryptStream( plainStream, chiperStream);
    Memo1.Lines.Add( 'Base64 encoding of ciphertext = ' + TPLB3.StreamUtils.Stream_to_Base64( chiperStream));
    Memo1.Lines.Add( 'Length of ciphertext = ' + IntToStr( chiperStream.Size) + ' bytes.');

    Codec1.Reset;
    chiperStream.Position := 0;
    plainStream.Size := 0;
    Codec1.DecryptStream( plainStream, chiperStream);
    ReconstructedPlainText := TPLB3.StreamUtils.Stream_to_string( plainStream, TEncoding.UTF8);
    Memo1.Lines.Add( 'Reconstructed plaintext = "' + ReconstructedPlainText + '"');

  finally
    plainStream.Free;
    chiperStream.Free;
    keyStream.Free;
    end
end;

This is using version 3.6.3 from https://github.com/SeanBDurkin/tplockbox This is for Delphi, not C++

Thanks for your efford, but the code still doesn't work with c++builder. — Sebastor, Jul 07 '16 at 08:08

LockBox3 DecryptStream can't create plain stream

1 Answers1