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

I have found what is parameter 3 error:

"Loading a key will return a CRYPT_ERROR_PARAM3 error if the key is a weak
key. cryptExportKey will export the correct parity-adjusted version of 
the key."

Hummm.... My test password is (text plain):
12345678abcdefgh87654321

I think this is not a weak key...

Thanks in advance...





Fernando Perez escribió:
> 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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