String handling issue with Free Pascal

[Sogcelak]

Thanks for your reply! Seems like I was a bit confusing. The function is nice, but it doesn't solve my issues. The code above was not part of my program, just a quick example of the source of my problem.

The main problem is that I can't get the program to test through all variations. It's a mathematical problem that I can't solve because of the weird way Pascal handles strings. This is what my program should really do:

Input1: Hash: e2075474294983e013ee4dd2201c7a73
Input2: Estimated maximum length of original characters: 4
Process:
Md5('0')->0
Md5('1')->0
Md5('2')->0
Md5('3')->0
.
.
.
Md5('9')->0
Md5('a')->0
Md5('b')->0
.
.
.
Md5('z')->0
Md5('00')->0
Md5('01')->0
Md5('02')->0
.
.
.
Md5('0a')->0
Mdt('0b')->0
.
.
.
Md5('a9')->0
Md5('aa')->0
Md5('ab')->0
Md5('ac')->Match Found
Md5('ad')->0
.
.
.
Md5('zzzz')->0

Output: 1 Match found: ac



Pascal has this nice function in the Md5 unit:

hash:=Md5Print(Md5String(string));

So hashing all the possible combinations, once they are generated, is not an issue.

See if there is a match is not an issue, since a single 'if' condition in the loop will do fine.

Making the program generate all the possible variations is the issue, because I can't write a procedure that handles string lengths dynamically. In Pascal your string must have a defined length, and you can't change that. Only deleting from the string, or adding to a string will change its length and it makes things very complicated in this case.

And no, lol I don't want to use it to break your passwords. Besides I wouldn't be able to. When I got my activation code it wasn't hashed in md5 so I guess your passwords aren't stored in md5 either (which is a pretty good decision as it is getting less and less secure). Cheers

[Sogcelak]

@User137
That will be implemented in the program, but first I need to optimize other things. If I want to add capitalized characters into the pool of characters my program uses, then it adds another 23 characters and it will make things a hell lot slower even without the NextChar function.

@Athena
That's a really cool guide you have written but erm... The basics, you say?? Unfortunately for me I could understand it until the second page, and there were things I didn't understand on the first page too(VCL thread??, TDXTimer??). It's just too advanced stuff for me. I don't know most of these functions. I don't know how classes handle these public and protected stuffs, or what's that constructor thing, how does inheriting work, what the hell does "try", "except", and "finally" do etc...etc... Hell, I don't even know how the OS exactly handles multithreading. How am I supposed to tell it how to do it, if I don't even know how it should be working? And finally, I also have no idea about how exactly can I use multithreading to fasten up this program. My program does one thing, and it is trying all different combinations of characters, so I don't see what tasks I could give to another thread. See I'm having difficulties with understanding the most basic things about multithreading, that's why I said I needed to study it a bit before I can implement it in my program.

[pitfiend]

@User137
That will be implemented in the program, but first I need to optimize other things. If I want to add capitalized characters into the pool of characters my program uses, then it adds another 23 characters and it will make things a hell lot slower even without the NextChar function.

@Athena
That's a really cool guide you have written but erm... The basics, you say?? Unfortunately for me I could understand it until the second page, and there were things I didn't understand on the first page too(VCL thread??, TDXTimer??). It's just too advanced stuff for me. I don't know most of these functions. I don't know how classes handle these public and protected stuffs, or what's that constructor thing, how does inheriting work, what the hell does "try", "except", and "finally" do etc...etc... Hell, I don't even know how the OS exactly handles multithreading. How am I supposed to tell it how to do it, if I don't even know how it should be working? And finally, I also have no idea about how exactly can I use multithreading to fasten up this program. My program does one thing, and it is trying all different combinations of characters, so I don't see what tasks I could give to another thread. See I'm having difficulties with understanding the most basic things about multithreading, that's why I said I needed to study it a bit before I can implement it in my program.

I think you need to have a look here. It's a Delphi "starters" site, were most of the language is explained. It is not very updated to last Delphi version, but the basics are there.

[AthenaOfDelphi]

I think you need to have a look here. It's a Delphi "starters" site, were most of the language is explained. It is not very updated to last Delphi version, but the basics are there.

I would also add http://www.pp4s.co.uk/main/tutorials.html. A good friend of mine has been using the PP4S tutorials to teach herself Delphi and she's found them pretty good although they do have a preference for Free Pascal.