C# Discussion Boards - CodeProject

26-Feb-09 10:05

Adam_Omer wrote:
any help?

Yes: buy a Sat Nav.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

[Message Deleted]

mobius11100126-Feb-09 8:56

mobius111001

26-Feb-09 8:56

[Message Deleted]

CPallini26-Feb-09 10:07

26-Feb-09 10:07

mobius111001 wrote:
I want to create a COM object that I will expose to 3rd parties.

Hum, interesting... What has it to do with the C# forum?

mobius11100126-Feb-09 10:08

mobius111001

26-Feb-09 10:08

Where else should it go? Does it count I'm writing the COM object in C#?

CPallini26-Feb-09 21:12

26-Feb-09 21:12

mobius111001 wrote:
Does it count I'm writing the COM object in C#?

Yes, indeed: you lost 100 man points for doing it that way.
Smile | :)

led mike26-Feb-09 10:09

led mike

26-Feb-09 10:09

CPallini wrote:
What has it to do with the C# forum?

He can't tell you that silly, you don't have proper security clearance. $Shucks | :-\$

Jim Crafton26-Feb-09 10:48

Jim Crafton

26-Feb-09 10:48

You guys are evil. Funny as hell, but evil nevertheless Smile | :)

¡El diablo está en mis pantalones! ¡Mire, mire!
SELECT * FROM User WHERE Clue > 0
0 rows returned
Save an Orange - Use the VCF!
VCF Blog
Just Say No to Web 2 Point Oh

led mike26-Feb-09 11:01

led mike

26-Feb-09 11:01

Did you seem my reply in the ASP.NET forum? Blush | :O

CPallini26-Feb-09 21:11

26-Feb-09 21:11

harold aptroot26-Feb-09 11:50

harold aptroot

26-Feb-09 11:50

Do they requirements specify how strong the encryption needs to be?

The requirements are unrealistic. It is in fact impossible without relying on user input*. You can use encryption of course, but it will not do anything besides wasting valuable resources. It will bar only the worst pseudo cracker that dares call himself/herself a cracker - and those are not the people that the company should be concerned about.
It's impossible because this is not a communication-channel you're trying to protect (where evil Eve only has knowledge about the communication itself), this amounts to trying to protect static data. It's impossible. Even if 3rd party programs have to use a "secret" key. They key is not secret, because the 3rd party program can access it. Thus, so can anyone who has the 3rd party program. Even if it has to, for example, use yet an other key to decrypt the real key. Or a 3rd key to decrypt the 2nd key. Somewhere it will end in a piece of data that is readily available to anyone.

That leaves you with user input - that is, requiring that 3rd party software do not store the key inside itself, but asks the user to input it. Sure the users could leak it, but at least the data itself doesn't contain its own key.

However, and this is a much bigger problem, the very thing you're trying to protect with such heavy locks is still unprotected. That is, to use it directly requires opening the locks.. but what's to keep anyone from dumping the locks? Decompile(.NET - obfuscators will not stop real crackers)/disassemble(native) the dll, delete the encryption code, and recompile/re-assemble..
The only people you'd successfully protect from, are people from which you have little to fear.

Regex Problem

musefan26-Feb-09 8:35

26-Feb-09 8:35

Hi all,

I am having a little trouble with Regex.

Basically i have a text file that i am trying to parse.

In this file i know there will be a number of names, these names will always use 100 bytes of space, if the name, in plain ASCII code, is less then 100 bytes the remainder of the space is filed with 0xFF

My regex code is as follows.

streamreader sr = new streamreader("file.txt");
string text = sr.ReadToEnd();
sr.close();

string pattern = @"[A-Za-z0-9]|\xFF{100}";

Regex = new Regex(pattern);

foreach(Match match in Regex.Matches(text))
{
   //not getting the result i expect, which i can clearly see if a HexEditor

}

I think the problem is with the \xFF part of the program, as a simple regex expression such as @"\xFF" returns no where near as many 0xFF values as are present in the file

Thanks for any help

If only MySelf.Visible was more than just a getter...

A person can produce over 5 times there own body weight in excrement each year... please re-read your questions before posting

PIEBALDconsult26-Feb-09 9:01

PIEBALDconsult

26-Feb-09 9:01

How about something like:

@"[A-Za-z0-9\xFF]{100}";

(Untested)

And about whitespace?

musefan26-Feb-09 10:15

26-Feb-09 10:15

thanks for your reply,

I have tried your suggestion too and get the same results. white space characters in addition to basic symbols may be present but for now im just looking to get this one working as i am certain the HEX value is what is causing me problems

If only MySelf.Visible was more than just a getter...

A person can produce over 5 times there own body weight in excrement each year... please re-read your questions before posting

Luc Pattyn26-Feb-09 11:01

Luc Pattyn

26-Feb-09 11:01

Hi,

ReadToEnd reads data as text, i.e. it applies an encoding to interpret the bytes and returns a Unicode string. Are you sure your text still holds characters with the value \u00FF?

I suggest you print out a few hundred chars in hex and check.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets

modified on Sunday, June 12, 2011 8:43 AM

PIEBALDconsult26-Feb-09 12:46

PIEBALDconsult

26-Feb-09 12:46

Oh, yeah, I hadn't thought of that.

musefan26-Feb-09 23:53

26-Feb-09 23:53

Thanks Luc, correct as allways Smile | :)

Printed the chars out as ints and found they where much higher than i was expecting. the thing i found unusual thou, atleats in my opinion, was that FF became 65333 as did a number of other Hex values over D8 (maybe lower values but i didnt see any others)

is there any reason why FF should not translate to 00FF?

Anyway my resulting modification was to loop the BaseStream and use a string builder with each byte read. works just as i expect now Smile | :)

While on the subject. Do you know if it is possible to perform a Regex search on the file itself?

i understand that a full string is required to ensure patterns are not split but it just seems bad to load the whole file into memory, even if its small in relation to RAM.

Initial i had my own file search that used keyword that allowed wildcards directly with the BaseStream, but this only works when there are contant values to identify.

I would have a keyword class and a method that takes a byte value, if that value matches the keyword at index 0 it incremets a counter so the next byte passed in is checked against index 1. if the count equals the keyword length then the function returns true (a match) then i can process.

I just think it would be good for regex to have a similar option because at the minute i can not handle a progress bar update until the regex has found matches. Possibly regex was not meant for file searching and more for validation of string values.

Anyway lol, thanks again

If only MySelf.Visible was more than just a getter...

A person can produce over 5 times there own body weight in excrement each year... please re-read your questions before posting

Luc Pattyn27-Feb-09 1:26

Luc Pattyn

27-Feb-09 1:26

Hi musefan,

whne you read text from a file, an encoding is used; you can specify one explicitly, most methods (e.g. File.ReadAllText) allow you to specify one; or you get your system's default encoding implicitly, which depends on regional settings.

I expect the regional setting ("code page") to be such that a lot of special characters get encoded in the byte value range [0x80, 0xFF], in order to save bytes in a file (and make it region-dependent!).
As an example, in Western Europe the default code page is 1252, which puts the Euro sign at 0x80, although there also is a Unicode character for it (0x20AC). So by default, reading a file containing 0x80 will result in a string with a 0x20AC at that position.

No, Regex does not work on files or streams, it needs a string.

No, progress indication is not really possible when you ask for a bulk operation such as File.ReadAllLines, a Regex operation, an SQL database operation, etc. Progress indication is available only when you implement it, which implies there are many steps in the job, possibly forcing you to cut the job in small steps (and forego the big methods such as ReadAllLines, and all Regex stuff).

I'm not a very big fan of Regex for your needs, I would have coded that with direct byte or char manipulations on the stream. Not sure whether I would chose bytes or chars though, probably bytes since your file does not really qualify as text, due to the 0xFF stuff.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

modified on Sunday, June 12, 2011 8:43 AM

musefan27-Feb-09 1:44