Re: [Lazarus] Encryption compatible with .net

[Graeme Geldenhuys]

On 2015-11-15 05:30, Gabriele Cappelletto wrote:
> what's the code to decrypt it with DCPCrypt?


Here is one usage example... This is actually the DES3 self-test code

===
procedure test;
const
  Key: array[0..23] of byte =
($01,$23,$45,$67,$89,$ab,$cd,$ef,$fe,$dc,$ba,$98,
 $76,$54,$32,$10,$89,$ab,$cd,$ef,$01,$23,$45,$67);// whatever
your key is
  PlainText: array[0..7] of byte=
($01,$23,$45,$67,$89,$ab,$cd,$e7);
  CipherText: array[0..7] of byte=
($de,$0b,$7c,$06,$ae,$5e,$0e,$d5);
var
  Cipher: TDCP_3des;
  Block: array[0..7] of byte;
begin
  dcpFillChar(Block, SizeOf(Block), 0); // initialize block to 0's
  Cipher:= TDCP_3des.Create(nil);
  Cipher.Init(Key,Sizeof(Key)*8,nil);
  Cipher.EncryptECB(PlainText,Block); // encrypt to Block
  Result:= CompareMem(@Block,@CipherText,Sizeof(CipherText));
  Cipher.DecryptECB(Block,Block); // decrypt the data in Block
  Result:= Result and CompareMem(@Block,@PlainText,Sizeof(PlainText));
  Cipher.Free;
end;

===


Here is another example where DCPCrypt is used to decrypt a file. It
used a different cipher and hash, but the usage would be the same for
DES or DES3.


==
procedure TDecryptDCPCrypt.DecryptFile(const pSrcFile, pDestFile: string);
var
  SrcFileStream, DestFileStream: TFileStream;
  DestPath: string;
  lSrc, lDest: string;
begin
  lSrc := tiFixPathDelim(pSrcFile);
  lDest := tiFixPathDelim(pDestFile);

  if FileExists(lSrc) then
  begin
SrcFileStream  := TFileStream.Create(lSrc, fmOpenRead);
DestFileStream := TFileStream.Create(lDest, fmCreate);

try
  DestPath := ExtractFilePath(lDest);
  if not DirectoryExists(DestPath) then
CreateDir(DestPath);

  try
FCipher.InitStr(cDecryptKey, TDCP_haval);
FCipher.DecryptStream(SrcFileStream, DestFileStream,
LongWord(SrcFileStream.Size));
FCipher.Burn;
  except
on E: Exception do
begin
  Log(E.Message, lsError);
  raise ESlideDecryptionFailed.Create('Failed to decrypt slide <'
  + lSrc + '>' + tiLineEnd +  'Error: ' + E.Message);
end;
  end;  { try.. except }

finally
  SrcFileStream.Free;
  DestFileStream.Free;
end;  { try..finally }
  end  { if }
  else
Log('pSrcFile does NOT exist!', lsError);
end;
==

Regards,
  - Graeme -

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Re: [Lazarus] Encryption compatible with .net

[Sven Barth]

Am 15.11.2015 06:31 schrieb "Gabriele Cappelletto" <
cappellettogabri...@yahoo.it>:
>
>
>
> Il 14/11/2015 18:11, Graeme Geldenhuys ha scritto:
> > On 2015-11-14 09:44, Gabriele Cappelletto wrote:
> >> the .net DESCryptoServiceProvider.
> > Please show how the data was encrypted... The exact code snippet would
> > be useful. I could then show you how to use DCPCrypt with the same
> > settings to decrypt it.
> >
> > Without knowing how it was encrypted, there is no way anybody can show
> > you code on how to decrypt it.
> >
> > Regards,
> >   - Graeme -
> > Ok thanks. We start from the opposite. cryptographer a string with
vb.net with the following code, what's the code to decrypt it with DCPCrypt?
>
> Ok thanks. We start from the opposite. cryptographer a string with
> vb.net with the following code, what's the code to decrypt it with
DCPCrypt?
>
> Dim Key() As Byte = {}
> Dim IV() As Byte = {1, 2, 3, 4, 5, 6, 7, 8}
>
> Dim KeyStr As String = "cicciob1"
> Dim vector As String = "12345678"
> Dim inputByteArray(TextBox3.Text.Length) As Byte
> Dim des As New DESCryptoServiceProvider
> 'des.Mode = CipherMode.CBC
> 'des.Padding = PaddingMode.Zeros
> Key = System.Text.Encoding.UTF8.GetBytes(KeyStr)
> inputByteArray = Encoding.UTF8.GetBytes(TextBox3.Text)
>
> Dim ms As New MemoryStream
> Dim cs As New CryptoStream(ms, des.CreateEncryptor(Key, IV),
> CryptoStreamMode.Write)
> cs.Write(inputByteArray, 0, inputByteArray.Length)
> cs.FlushFinalBlock()
>
> TextBox4.Text = Convert.ToBase64String(ms.ToArray)

What did you try in the Pascal side (code please)? Did you decode the
Base64 stream before passing the data to the decryption?

Regards,
Sven
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Re: [Lazarus] Encryption compatible with .net

[DougC]

After quick look I noticed that



var

  Vector : array of Byte;



  SetLength(Vector, 8);

  Vector[0] := 1;

  Vector[1] := 2;

  Vector[2] := 3;

  Vector[3] := 4;

  Vector[4] := 5;

  Vector[5] := 6;

  Vector[6] := 7;

  Vector[7] := 8;



does not match



  Dim vector As String = "12345678"



Should be something like

  Vector[0] := '1';

  Vector[1] := '2';

  Vector[2] := '3';

  Vector[3] := '4';

  Vector[4] := '5';

  Vector[5] := '6';

  Vector[6] := '7';

  Vector[7] := '8';



I didn't look at the rest.




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Re: [Lazarus] Encryption compatible with .net

[DougC]

So why is vector in your code? Including irrelevant parts just makes it harder 
for others to help you.



Rewrite your Pascal code to use the same variables as the VB code!





  On Sun, 15 Nov 2015 06:56:09 -0500 Gabriele Cappelletto 
cappellettogabri...@yahoo.it wrote 




But the cipther constructor does not refer to vector, but the variable IV. 
Vector is not used in this example






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Re: [Lazarus] Encryption compatible with .net

[Gabriele Cappelletto]

  
  
I have try with this code but not work, I have test the function
give me the same result:

var
  Cipher: TDCP_des;
  KeyStr: string;
  TextIn, TextOut : String;
  Hash: TDCP_sha1;
  Digest: array[0..19] of byte;
  Vector : array of Byte;

  src, enc, b64: TBytes;
  index, lunghezza, blocksize, paddingsize: integer; 

begin
    SetLength(Vector, 8);

  Vector[0] := 1;
  Vector[1] := 2;
  Vector[2] := 3;
  Vector[3] := 4;
  Vector[4] := 5;
  Vector[5] := 6;
  Vector[6] := 7;
  Vector[7] := 8;

  Cipher := TDCP_des.Create(Self); 
   Cipher.Init('cicciob1',Length('cicciob1')*8, addr(Vector[0]));
  TextIn := Edit1.Text;
  lunghezza := Length(TextIn);
  index := SizeOf(TextIn);
  blocksize := Cipher.BlockSize div 8;
  paddingsize:= blocksize - (lunghezza mod blocksize);
  Inc(lunghezza, paddingsize);
  SetLength(TextIn, lunghezza);
  for index:=paddingsize downto 1 do
  begin
   TextIn[lunghezza - index] := char(0); 
  end;
  index := Length(TextOut);
  SetLength(TextOut, lunghezza);
  Cipher.EncryptCBC(TextIn[1], TextOut[1], length(TextIn));
  Edit2.Text:=EncodeStringBase64(TextOut); 






Il 15/11/2015 11:59, Sven Barth ha
  scritto:


  Am 15.11.2015 06:31 schrieb "Gabriele Cappelletto" :
>
>
>
> Il 14/11/2015 18:11, Graeme Geldenhuys ha scritto:
> > On 2015-11-14 09:44, Gabriele Cappelletto wrote:
> >> the .net DESCryptoServiceProvider.
> > Please show how the data was encrypted... The exact
code snippet would
> > be useful. I could then show you how to use DCPCrypt
with the same
> > settings to decrypt it.
> >
> > Without knowing how it was encrypted, there is no way
anybody can show
> > you code on how to decrypt it.
> >
> > Regards,
> >   - Graeme -
> > Ok thanks. We start from the opposite. cryptographer a
string with vb.net
with the following code, what's the code to decrypt it with
DCPCrypt?
>
> Ok thanks. We start from the opposite. cryptographer a
string with
> vb.net
with the following code, what's the code to decrypt it with
DCPCrypt?
>
>         Dim Key() As Byte = {}
>         Dim IV() As Byte = {1, 2, 3, 4, 5, 6, 7, 8}
>
>         Dim KeyStr As String = "cicciob1"
>         Dim vector As String = "12345678"
>         Dim inputByteArray(TextBox3.Text.Length) As Byte
>         Dim des As New DESCryptoServiceProvider
>         'des.Mode = CipherMode.CBC
>         'des.Padding = PaddingMode.Zeros
>         Key = System.Text.Encoding.UTF8.GetBytes(KeyStr)
>         inputByteArray =
Encoding.UTF8.GetBytes(TextBox3.Text)
>
>         Dim ms As New MemoryStream
>         Dim cs As New CryptoStream(ms,
des.CreateEncryptor(Key, IV),
> CryptoStreamMode.Write)
>         cs.Write(inputByteArray, 0, inputByteArray.Length)
>         cs.FlushFinalBlock()
>
>         TextBox4.Text = Convert.ToBase64String(ms.ToArray)
  What did you try in the Pascal side (code please)? Did you
decode the Base64 stream before passing the data to the
decryption?
  Regards,
Sven
  
  
  
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Re: [Lazarus] Encryption compatible with .net

[Gabriele Cappelletto]

  
  
But the cipther constructor does not refer to vector, but the
variable IV. Vector is not used in this example

Il 15/11/2015 12:44, DougC ha scritto:


  
  
After quick look I noticed that



var

  Vector : array of Byte;



  SetLength(Vector, 8);

  Vector[0] := 1;

  Vector[1] := 2;

  Vector[2] := 3;

  Vector[3] := 4;

  Vector[4] := 5;

  Vector[5] := 6;

  Vector[6] := 7;

  Vector[7] := 8;



does not match



  Dim vector As String = "12345678"



Should be something like

  Vector[0] := '1';

  Vector[1] := '2';

  Vector[2] := '3';

  Vector[3] := '4';

  Vector[4] := '5';

  Vector[5] := '6';

  Vector[6] := '7';

  Vector[7] := '8';



I didn't look at the rest.



  
  
  
  
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Re: [Lazarus] Encryption compatible with .net

[payl]

I see another problem: Your pascal implementation sets key badly. I think  
it should be 'key'[1]. However as I didn't even use buffer with constant  
string so I might be wrong.
You should also try to encrypt longer messages to see if first block is  
intact because then it's padding problem.
Please also note that such implementation is insecure because IV is  
static, key isn't derived with KDF, DES is insecure nowadays, and no  
integrity checking is done. So if you want your encryption to be of any  
security, fix these flaws.
Also consider cleaning up code so we don't get confused about unused  
variables.


(Btw. My first post on this mailing list - yay!)

W dniu .11.2015 o 12:56 Gabriele Cappelletto  
 pisze:


But the cipther constructor does not refer to vector, but the variable  
IV. Vector is not used in this example


Il 15/11/2015 12:44, DougC ha scritto:

After quick look I noticed that

var
 Vector : array of Byte;

 SetLength(Vector, 8);
 Vector[0] := 1;
 Vector[1] := 2;
 Vector[2] := 3;
 Vector[3] := 4;
 Vector[4] := 5;
 Vector[5] := 6;
 Vector[6] := 7;
 Vector[7] := 8;

does not match

 Dim vector As String = "12345678"

Should be something like
 Vector[0] := '1';
 Vector[1] := '2';
 Vector[2] := '3';
 Vector[3] := '4';
 Vector[4] := '5';
 Vector[5] := '6';
 Vector[6] := '7';
 Vector[7] := '8';

I didn't look at the rest.



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[Lazarus] Encryption compatible with .net

[Gabriele Cappelletto]

I can not find a way to encrypt a file with Lazarus and decrypt it with
the .net DESCryptoServiceProvider. I tried with lockbox2, DCPcrypt but I
could not. Someone can give me the code to implement this in Lazarus?

Gabriele Cappelletto

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Re: [Lazarus] Encryption compatible with .net

[Gabriele Cappelletto]

Il 14/11/2015 18:11, Graeme Geldenhuys ha scritto:
> On 2015-11-14 09:44, Gabriele Cappelletto wrote:
>> the .net DESCryptoServiceProvider.
> Please show how the data was encrypted... The exact code snippet would
> be useful. I could then show you how to use DCPCrypt with the same
> settings to decrypt it.
>
> Without knowing how it was encrypted, there is no way anybody can show
> you code on how to decrypt it.
>
> Regards,
>   - Graeme -
> Ok thanks. We start from the opposite. cryptographer a string with vb.net 
> with the following code, what's the code to decrypt it with DCPCrypt?

Ok thanks. We start from the opposite. cryptographer a string with
vb.net with the following code, what's the code to decrypt it with DCPCrypt?

Dim Key() As Byte = {}
Dim IV() As Byte = {1, 2, 3, 4, 5, 6, 7, 8}

Dim KeyStr As String = "cicciob1"
Dim vector As String = "12345678"
Dim inputByteArray(TextBox3.Text.Length) As Byte
Dim des As New DESCryptoServiceProvider
'des.Mode = CipherMode.CBC
'des.Padding = PaddingMode.Zeros
Key = System.Text.Encoding.UTF8.GetBytes(KeyStr)   
inputByteArray = Encoding.UTF8.GetBytes(TextBox3.Text)
   
Dim ms As New MemoryStream
Dim cs As New CryptoStream(ms, des.CreateEncryptor(Key, IV),
CryptoStreamMode.Write)
cs.Write(inputByteArray, 0, inputByteArray.Length)
cs.FlushFinalBlock()

TextBox4.Text = Convert.ToBase64String(ms.ToArray)



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Re: [Lazarus] Encryption compatible with .net

[leledumbo]

> I can not find a way to encrypt a file with Lazarus and decrypt it with 
the .net DESCryptoServiceProvider. I tried with lockbox2, DCPcrypt but I 
could not. Someone can give me the code to implement this in Lazarus?

DES is a standard encryption. If you can't decrypt what's encrypted by a
standard encryption, regardless of languages and libraries, then either the
library or your way to use the library is wrong. Ensure all properties (key
size, block size, initialization vector, whatever) you use is the same and
the resulting data is also of the same type and structure. All in all, show
what you've done.



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Re: [Lazarus] Encryption compatible with .net

[Gabriele Cappelletto]

I tried to put all the same properties, but I could not. There is
probably something I did wrong. So I ask if someone can give me the
code. is two days I feel.


Il 14/11/2015 16:36, leledumbo ha scritto:
>> I can not find a way to encrypt a file with Lazarus and decrypt it with 
> the .net DESCryptoServiceProvider. I tried with lockbox2, DCPcrypt but I 
> could not. Someone can give me the code to implement this in Lazarus?
>
> DES is a standard encryption. If you can't decrypt what's encrypted by a
> standard encryption, regardless of languages and libraries, then either the
> library or your way to use the library is wrong. Ensure all properties (key
> size, block size, initialization vector, whatever) you use is the same and
> the resulting data is also of the same type and structure. All in all, show
> what you've done.
>
>
>
> --
> View this message in context: 
> http://free-pascal-lazarus.989080.n3.nabble.com/Lazarus-Encryption-compatible-with-net-tp4045490p4045492.html
> Sent from the Free Pascal - Lazarus mailing list archive at Nabble.com.
>
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Re: [Lazarus] Encryption compatible with .net

[Graeme Geldenhuys]

On 2015-11-14 09:44, Gabriele Cappelletto wrote:
> the .net DESCryptoServiceProvider.

Please show how the data was encrypted... The exact code snippet would
be useful. I could then show you how to use DCPCrypt with the same
settings to decrypt it.

Without knowing how it was encrypted, there is no way anybody can show
you code on how to decrypt it.

Regards,
  - Graeme -

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My public PGP key:  http://tinyurl.com/graeme-pgp

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