[URGENT] help extracting FoxPro DBF Encrypted fields

Hi everyone.

I'm working with a Foxpro DBF database, but I'm not using Visual Foxpro to read the data. I'm doing this from C#.Net.

In fact .. I've never really used Foxpro before.

My problem is as follows:

In C# and Crystal Reports .. a lot of the string fields simply return blank strings (i.e. "")

When I view the table in FoxPro, they are fixed-width character fields, and browsing the table shows that they contain a bunch of special ASCII characters.
A
#
E

I know that the data is there, because when I run the FoxPro application which came with the database files I can see the actually data (actually numerical decimal values).

So .. my question is thus:

Having FoxPro installed .. how would I go about decrypting these files

Secondly ... how could I then read these values through an ODBC or DSN data source

All help appreciated .. this is quite urgent.

thankyou

Martiankeeper

Answer this question

[URGENT] help extracting FoxPro DBF Encrypted fields

qrz
Thankyou for the swift reply

I'm assuming that there is no standard "encrypt" / "decrypt" methods, functions or tools in Foxpro

The problem is that the vendor is not interested and refuses to co-operate
(he can't be bothered to do the work himself, but at the same time doesn't want someone else access to the system that he wrote).

Which, as I'm sure you can imagine, is very frustrating.

(any encryption cracking tools or services out there )
Waldis
It sounds like the VFP app is decrypting the data on the fly.

I think you will need the vendors help.

Dave M.
Rob Redbeard
Is it really encrypted data or are you looking at it wrong

You say they're numerical decimal values and getting string fields instead In foxpro numerical values are stored in different ways and some of them if not casted to right type looks like special ASCII chars (memory representation of an integer or real for example).

Would you show your C# code (1.1 or 2.0 ).

PS: Instead of ODBC use OLEDB. VFP has VFPOLEDB driver downloadable from MS VFP site.
AmitInnani
Oooops ...

hehe ... I did copy and paste, but trimmed out loads of other stuff (which doesn't affect this problem .. and is sensitive information).

so .. apart from my previous typos ...
any ideas
cmyster

Actually FoxPro dose have one, but encryption requires an encryption key used for Encrypting and decrypting.

If this is the method he used. Perhaps you can persuade (ie bride) your vendor for the encryption key. Than handle the rest yourself.

See:

http://www.code-magazine.com/article.aspx quickid=0203041&page=3

also

http://doc.advisor.com/Articles.nsf/nl/12579

Dave M.
julio666

"vendor is not interested and refuses to co-operate" - they never do.

You are facing a formidable task. It is called binary file analysis/parsing. I may be in your shoes a month from now. It is actually the end goal of a long series of projects of mine. I did some preliminary search and the results are not encouraging so far.

I can leave here a few links some of them barely relevant but still may be useful. If you get anywhere, share your experience. The last website contains all sorts of codes. They also welcome any new discoveries.

http://sweetscape.fileburst.com/010edrefmanual.pdf
http://www.byronref.com/rmb/pxspecs.htm
http://www.clicketyclick.dk/databases/xbase/format/dbf.html#DBF_STRUCT
http://www.dbase.com/KnowledgeBase/int/db7_file_fmt.htm
http://www.packetsnifferanalyzers.com/ OVRAW=packet%20sniffer%20&OVKEY=packet%20sniffer&OVMTC=standard
http://www.the-oasis.net/
http://www.wotsit.org/

Thanks.
Erathus
What typos

LeszekG

C# Code I am using.

// Initialize database connection.
OleDbConnection _connection = new OleDbConnection(
@"Provider=vfpoledb.1;" +
@"Data Source=C:\MyDataTable\;" +
@"Collating Sequence=general");

try
{
// SQL select statement
string strSelect = "SELECT * FROM MyTable";

OleDbDataAdapter _dataAdapter = new OleDbDataAdapter(strSelect, _connection);

OleDbCommandBuilder _commandBuilder = new OleDbCommandBuilder(_dataAdapter);

DataSet _dataset = new DataSet();
_dataset.Clear();

_dataAdapter.FillSchema(_dataset, SchemaType.Source);
_dataAdapter.Fill(_dataset);
}
foreach(DataRow _datarow in _dataset.Tables[0].Rows)
{
Console.Writeline ( _datarow["myField"] );
}
finally
{
_connection.Close();
}

When I ask for the _datarow values .. it doesn't even return a data type ... it's just "" (blank string).

If I try and cast it to a numerical data type it returns an error (saying that blank strings cannot be cast to integers).

So .. not much luck there methinks.

Martin

Buffy6

Theoretical using a decompiler, one may be able to get the encryption key and Decrypt his\her's data files.

I’m not sure I doing do is legal or ethical if one was only tying to get there own data.

Dave M.
jcarranza
try block is missing closing braces and Writeline.
Fredrik G
OK to me it looks like this code has typos and wouldn't even compile. Considering you have the right version it might be encrypted data (and you should have already tried to preview data in VS IDE).
[URGENT] help extracting FoxPro DBF Encrypted fields

Answer this question