Re: 3DES and how to change mode and set IV.

Hello Wolfgang,  first of all, thanks by your example...

I have tried this:

==================
procedure TForm3.DoEncrypt(InputFilename: string; OutputFilename: 
string; MyPassword: string);
var
  cryptContext : TCryptContext;
  key          : AnsiString;
  data         : TMemoryStream;

begin
  data := TMemoryStream.Create;
  data.LoadFromFile(InputFileName);

  key := MyPassword;

  try
    cryptContext := TCryptContext.Create(CRYPT_ALGO_3DES);
    try

      cryptContext.SetAttribute(CRYPT_CTXINFO_MODE, ord(CRYPT_MODE_ECB));
      cryptContext.SetAttributeString(CRYPT_CTXINFO_KEY, key);
      //---> ECB mode  --- 
cryptContext.SetAttributeBinary(CRYPT_CTXINFO_IV, @iv, 8);
      cryptContext.Encrypt(@data, data.size);  // Here the error...

    finally
      cryptContext.Destroy;
    end;
    data.SaveToFile(OutputFilename);
  except
     on E:Exception do
       ShowMessage(E.ClassName + ': ' + E.Message);
  end;
end;
==================

But I have _always_ the error:
     Bad argument, parameter 3

but I don't know what is the parameter 3.

Greetings...

GMX escribió:
> The Delphi Interface for cryptlib contains all functions needed
> for this job. But the "Delphi-like" interface DelphiCryptlib.pas
> with object oriented features for cryptlib does not contain
> methods for the low level features of cryptlib.
>
> But it is very simple to expand the objects and methods and
> implement any "missing" feature. I give you a sample for the
> low level encoding/decoding as suggested by Peter below.
>
> The Delphi interface module DelphiCryptlib.pas is available
> from my Delphi-cryptlib pages http://cryptlib.sogot.de
>
> Wolfgang Gothier
> --
>
> Source samples:
> ------------------------------------------------------------------
> program SampleForFernandoPerez;
>
> {$APPTYPE CONSOLE}
>
> uses
>    SysUtils,
>    DelphiCryptlib,
>    cryptlib,
>    LowLevelDelphiCryptlib in 'LowLevelDelphiCryptlib.pas';
>
> var
>    cryptContext: TCryptContext;
>    key : AnsiString = 'My Special Key 1';
>    iv : array[0..7] of byte = (8,7,6,5,4,3,2,1);
>    data: array[1..16] of byte = (0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5);
>
> begin
>    try
>      cryptContext := TCryptContext.Create(CRYPT_ALGO_3DES);
>      with cryptContext do begin
>        SetAttribute(CRYPT_CTXINFO_MODE, ord(CRYPT_MODE_CBC));
>        SetAttributeString(CRYPT_CTXINFO_KEY, key);
>        SetAttributeBinary(CRYPT_CTXINFO_IV, @iv, 8);
>        Encrypt(@data, SizeOf(data));
>      end;
>      cryptContext.Destroy;
>
>      { the decryption follows as sample }
>      cryptContext := TCryptContext.Create(CRYPT_ALGO_3DES);
>      cryptContext.SetAttribute(CRYPT_CTXINFO_MODE, ord(CRYPT_MODE_CBC));
>      cryptContext.SetAttributeString(CRYPT_CTXINFO_KEY, key);
>      cryptContext.SetAttributeBinary(CRYPT_CTXINFO_IV, @iv, 8);
>      cryptContext.Decrypt(@data, SizeOf(data));
>      cryptContext.Destroy;
>
>    except
>      on E:Exception do
>        Writeln(E.Classname, ': ', E.Message);
>    end;
> end.
>
> ------------------------------------------------------------------
> ------------------------------------------------------------------
>
> unit LowLevelDelphiCryptlib;
>
> interface
>
> uses
>    DelphiCryptlib,
>    cryptlib;
>
> type
>    TCryptContext = class(TCryptObject)
>      constructor Create(algo: CRYPT_ALGO_TYPE);
>      procedure Encrypt(data: Pointer; length: Integer);
>      procedure Decrypt(data: Pointer; length: Integer);
>    end;
>
> implementation
>
> constructor TCryptContext.Create(algo: CRYPT_ALGO_TYPE);
> var
>    err: Integer;
> begin
>    err := cryptCreateContext(CryptHandle, CRYPT_UNUSED, algo);
>    if err < 0 then
>      raise ECryptError.Create(err, 'cryptCreateContext');
> end;
>
> procedure TCryptContext.Encrypt(data: Pointer; length: Integer);
> var
>    err: Integer;
> begin
>    err := cryptEncrypt( CryptHandle, data, length );
>    if err < 0 then
>      raise ECryptError.Create(err, 'cryptEncrypt');
> end;
>
> procedure TCryptContext.Decrypt(data: Pointer; length: Integer);
> var
>    err: Integer;
> begin
>    err := cryptDecrypt( CryptHandle, data, length );
>    if err < 0 then
>      raise ECryptError.Create(err, 'cryptDecrypt');
> end;
>
> end.
> ------------------------------------------------------------------
>
>
> -------- Original Message  --------
> Subject: Re: [Cryptlib] 3DES and how to change mode and set IV.
> From: Fernando Perez <[email protected]>
> To: Peter Gutmann <[email protected]>
> Date: Wed Sep 02 2009 16:46:17 GMT+0200
>
>   
>> Hello Peter, sorry my delay I have been testing and trying without 
>> success... :-(
>>
>> Perhaps the big problem is that we are doing all of this on Delphi 
>> (object Pascal language) and we have not could to get this to work.
>>
>> Thanks anyway...
>>
>> Greetings..
>>
>>
>>
>>
>>
>> Peter Gutmann escribió:
>>     
>>> Fernando Perez <[email protected]> writes:
>>>
>>>  
>>>       
>>>> I need to crypt/decrypt with cryptlib, but I need to support all mode 
>>>> formats
>>>> (cbc, ecb, ....) and IV's.   I have read documentation, search into 
>>>> but I
>>>> have no luck to get info on how to change cbc-mode or set the IV.  I 
>>>> need a
>>>> step by step functions to execute (an esquematic view)...
>>>>     
>>>>         
>>> To set the IV, see "Working with Initialisation Vectors" in the 
>>> manual, or
>>> "Conventional Encryption" for a complete code example.  Here's a 
>>> sample, for
>>> CBC mode:
>>>
>>>   CRYPT_CONTEXT cryptContext;
>>>
>>>   cryptCreateContext( &cryptContext, CRYPT_UNUSED, CRYPT_ALGO_3DES );
>>>   cryptSetAttribute( cryptContext, CRYPT_CTXINFO_MODE, CRYPT_MODE_CBC );
>>>   cryptSetAttributeString( cryptContext, CRYPT_CTXINFO_KEY, key, 16 );
>>>   cryptSetAttributeString( cryptContext, CRYPT_CTXINFO_IV, iv, 8 );
>>>   cryptEncrypt( cryptContext, data, length );
>>>   cryptDestroyContext( cryptContext );
>>>
>>> Peter.
>>>       
>
>
>   

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