Runtime exception on encrypting/decrypting streams using DCP

[circuitchaser]

Hello all,

I trying to make enc/dec using the DCP suite, but I get the "Stream Read Error" from EReadError class on executing the function below.

Code: Pascal  [Select][+][-]

1. function TForm1.EncriptDecript: boolean;
2. var
3.   cipher, decipher: TDCP_rijndael;
4.   data, outputData: TBytes;
5.   raw, encripted, decripted: TMemoryStream;
6. begin
7.   try
8.     raw:= TMemoryStream.Create;
9.     encripted:= TMemoryStream.Create;
10.     decripted:= TMemoryStream.Create;
11.  
12.     SetLength(data, 2);
13.     SetLength(outputData, 2);
14.  
15.     data[0]:= 157;
16.     data[1]:= 210;
17.  
18.     raw.Position:= 0;
19.     raw.Write(data, sizeof(data));
20.  
21.     try
22.       cipher:= TDCP_rijndael.Create(nil);
23.       cipher.BlockSize:= 256;
24.       cipher.InitStr('test', TDCP_sha256);
25.       cipher.EncryptStream(raw, encripted, raw.Size);
26.       cipher.Burn;
27.       cipher.Free;
28.  
29.       decipher:= TDCP_rijndael.Create(nil);
30.       decipher.BlockSize:= 256;
31.       decipher.InitStr('test', TDCP_sha256);
32.       decipher.DecryptStream(encripted, decripted, encripted.Size);
33.       decipher.Burn;
34.       decipher.Free;
35.  
36.       decripted.Position:= 0;
37.       decripted.ReadBuffer(outputData, SizeOf(outputData));
38.  
39.       result:= true;
40.     except
41.       ShowMessage('Fatal error.');
42.     end;
43.   finally
44.     FreeAndNil(decripted);
45.     FreeAndNil(encripted);
46.     FreeAndNil(raw);
47.   end;
48. end;  
49.  

The objective is read the "outputData" identical as "data" byte array after e/d operations.

Can someone help me please?
Thanks!

[dsiders]

Hello all,

I trying to make enc/dec using the DCP suite, but I get the "Stream Read Error" from EReadError class on executing the function below.

Code: Pascal  [Select][+][-]

1. function TForm1.EncriptDecript: boolean;
2. var
3.   cipher, decipher: TDCP_rijndael;
4.   data, outputData: TBytes;
5.   raw, encripted, decripted: TMemoryStream;
6. begin
7.   try
8.     raw:= TMemoryStream.Create;
9.     encripted:= TMemoryStream.Create;
10.     decripted:= TMemoryStream.Create;
11.  
12.     SetLength(data, 2);
13.     SetLength(outputData, 2);
14.  
15.     data[0]:= 157;
16.     data[1]:= 210;
17.  
18.     raw.Position:= 0;
19.     raw.Write(data, sizeof(data));
20.  
21.     try
22.       cipher:= TDCP_rijndael.Create(nil);
23.       cipher.BlockSize:= 256;
24.       cipher.InitStr('test', TDCP_sha256);
25.       cipher.EncryptStream(raw, encripted, raw.Size);
26.       cipher.Burn;
27.       cipher.Free;
28.  
29.       decipher:= TDCP_rijndael.Create(nil);
30.       decipher.BlockSize:= 256;
31.       decipher.InitStr('test', TDCP_sha256);
32.       decipher.DecryptStream(encripted, decripted, encripted.Size);
33.       decipher.Burn;
34.       decipher.Free;
35.  
36.       decripted.Position:= 0;
37.       decripted.ReadBuffer(outputData, SizeOf(outputData));
38.  
39.       result:= true;
40.     except
41.       ShowMessage('Fatal error.');
42.     end;
43.   finally
44.     FreeAndNil(decripted);
45.     FreeAndNil(encripted);
46.     FreeAndNil(raw);
47.   end;
48. end;  
49.  

The objective is read the "outputData" identical as "data" byte array after e/d operations.

Can someone help me please?
Thanks!

You did not reset the position for the Encripted stream after it was written by Cipher and before it was read by Decipher.

Code: Pascal  [Select][+][-]

1. Encipted.Position := 0;

[circuitchaser]

Hello dsiders, thanks for the answer.

You did not reset the position for the Encripted stream after it was written by Cipher and before it was read by Decipher.

I changed the code, but the error persists.
See:

Code: Pascal  [Select][+][-]

1. try
2.       cipher:= TDCP_rijndael.Create(nil);
3.       cipher.BlockSize:= 256;
4.       cipher.InitStr('test', TDCP_sha256);
5.       cipher.EncryptStream(raw, encripted, raw.Size);
6.       cipher.Burn;
7.       cipher.Free;
8.  
9.       //The change
10.       encripted.Position:= 0;
11.  
12.       decipher:= TDCP_rijndael.Create(nil);
13.       decipher.BlockSize:= 256;
14.       decipher.InitStr('test', TDCP_sha256);
15.       decipher.DecryptStream(encripted, decripted, encripted.Size);
16.       decipher.Burn;
17.       decipher.Free;
18.  
19.       decripted.Position:= 0;
20.       decripted.ReadBuffer(outputData, SizeOf(outputData));
21.  
22.       result:= true;
23.     except
24.       ShowMessage('Fatal error.');
25.     end;    
26.  

Note: when debugging, I saw from watches and noted the "encripted" shows "MEMORY: nil" on properties (attached images).

[TRon]

@circuitchaser:
It goes for every stream so also for your raw stream. You have written data to it yet expect the position to be at position 0 when you feed it to encryptstream.

Also when you read and write buffers to and from streams always use their index(ed byte) otherwise it will overwrite the types internal storage format.