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Closed 10 years ago.
I have the following code:
#include <iostream>
#include <string>
void main()
{
std::string str;
std::cin>>str;
if(str == "TheCorrectSerialNumber")
std::cout<<"Hello world!!!"<<std::endl;
}
I need a decompilation or disassemblering tool which can help me by doing below listed steps find the "TheCorrectSerialNumber". So the steps are:
decompile or diassembler the executable of my code
run the exe and type not the Correct Serial but something like “AAA”
find my “AAA” with what string is being compared and finally find out the "TheCorrectSerialNumber".
Please provide me also with directions how your suggested tool is doing above listed steps.
Thanks a lot!!!
NOTE: For those who tend to think that I want to crack someone’s code! First look ant my questions that I've asked just before and just after this question. I am a programmer and I need to concern about my codes security. Thus I have decided to crack my codes and to do some exercises on the other codes (on the sites that teach cracking there are a bunch of softs that are designed to be cracked) to understand how to deliver a secure code. If you know how people do cracking you probably will create more secure code that someone who doesn't know. And if you what to study how to crack you have to try. That is my point!
Depending on what platform you are on, you can use GDB (Gnu debugger) or IDA Pro.
I don't have much experience in reverse engineering on Windows, however Lena's tutorials are probably the best place to start in regards to reversing basic binaries. It'll run you through the basics of analyzing binaries at the assembly level and patching them. I believe it primarily makes use of ollydbg
Either you're doing something unethical or you're not. Either way you need something called a debugger and there will be one for your platform.
A debugger is a tool designed to help debug programs by attaching to a running piece of code and letting you examine it's state while running. Essentially you can view the state of the code (what's running where when etc) and state if the data. After all its all just a program counter and some memory, with a few registers thrown in to make life easy.
It is very easy to do with disassembling.
You need HIEW and W32DASM tools or OllyDbg (for example).
Just look at some examples of using this tools in youtube (cracking).
www.wasm.ru
www.cracklab.ru
Very helpful sites!!!!
Dude .. for something as trivial as this, just open it up in notepad, you'll find your "TheCorrectSerialNumber" .. probably right next to "Hello World!!!".
gray hat python http://nostarch.com/images/ghpython_cov.png
Let's assume you're not doing something illegal.
I can recommend the gray hat book for reverse engineering especially if you're already fluent with python.
Related
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Closed 12 years ago.
Days ago I created a program in Python to download stuff from the Internet, doing HTTP POST and GET and parsing JSON objects. I noticed some slow performance and I was thinking about writing it from scratch using another language, so I started to write it in C++ to make it faster. Finally I give up, C++ wasn't made for the Internet and it's very difficult to get something working.
I was thinking about giving C# or Java a try, which would you recommend? (I need my program to be fully cross-platform, other programming languages are valid too)
Edit: You can check the source code here: http://code.google.com/p/grooveapi/
Rewriting an IO bound application in a different language is unlikely to make any difference in its execution speed.
If you need it to be cross-platform: (i.e. you just write it once and it can run anywhere) Then Java or Python are your only options. This is because any C variant will need compiling specifically for the platform you intend to use it on.
My suggestion: Out of the two I would suggest Python. I have be educated in Java at University, and have learnt Python myself. Python is the language I turn to for web programming projects (in the form of Django on a larger scale) and the language used at companies I have worked for inside of their web applications.
Before you switch to another language... are you sure the performance problems are due to the language itself? It can very well be possible the problem is in the program, or the network latency or any other reason.
Don't blame the language before you've profiled your application carefully, maybe you have a bottleneck somewhere. The cost of a new development will be always very high, specially compared to a few line changes if you've found a problem in your code.
how did you notice "slow performance" when using python? I mean, python is slow, ok, but for your use case it shouldn't matter. Did you profile the code? Can you paste the code here so we can take a look and maybe improve it?
I don't know what kind of performance issues you had with your program in python but it usually does great for me ( scripts parsing log files that are huge take really little time for instance...).
now It all depends on the general purpose of this. If its just a script, no gui etc.. then you should definitely look into optimizing python, or doing some perl or php-cli script.
I'm not familiar with it first hand but ruby seems to have a big following and seems very "internet" oriented aswel.
If you do want to create something more than a script you have lots of options, c# is one of them, but it won't be cross platform, i'd go with java.
In the end I'd recommend rechecking your python code, it seems odd that its not doing what you want performance wise.... python is really good.
You should choose the language you feel most comfortable with. In most cases the performance of the scripting language is not the bottleneck. It is more important to get things done quickly and keep it maintainable. I would recommend you to choose Ruby or Python. If you have to get Python faster you still can choose to use JIT implementation like PyPy. Actually quite high traffic webapps, like YouTube, use Python.
I'd go with the good, old PHP! It has proven time and time again, that it is more than capable of doing this, and is quite easy to learn.
So my advice: Go with PHP!
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Closed 13 years ago.
C# is owned by Microsoft and Java is owned by Sun/Oracle. What dangers does that really expose to the users of these languages? Has anyone felt their code was "owned"? Do projects like Mono help keep the "owners" honest?
Please do not make this a holy war of languages. I just want to know if it's rational to avoid such languages or if that's just paranoia. An interview with the inventor of C++ got me thinking, but I also want to balance his thoughts with the thoughts of the community as a whole.
As compared to what? Since you put it in these terms, the original C and C++ languages are "owned" by Bell Labs.
Java is not "Owned", it is open source. If you find a bug in it that you absolutely cannot deal with, you CAN fix it. (There are both open source and closed source implementations, however)
I don't know if you can get the source code to C#, but since Mono copied it there IS an open source for that as well.
I don't know if there is a second source for the .net libraries.
As for the actual "Dangers" (Which was your real question, after all), it would be that the company decides not to release updates any longer--if they do, will the language wither and die or will it take off on it's own? Java is in the process of transition from one of these states to another. Sorry, don't know about C#.
There is also the (Perceived) danger I mentioned earlier about--can you fix it if you hundred-million dollar company absolutely needs it fixed in order to continue.
This was a more significant problem twenty years ago, these days the fact is that if it's a good stable language, this isn't something you ever need to worry about.
No such danger for C# language. It is an ISO standard. Formally it is owned by a committee. But Java is a trademark
Getting up in the morning is risky, but that doesn't keep the world under the covers.
I feel like this is one of those acceptable risks. In Java's case, companies have used it for the last 15 years or so to their benefit.
What's the alternative? Developing and maintaining your own language so you own it? That's what SAP did. It seems to have worked out for them, but it'd be interesting to calculate the cost they've incurred.
Bjarne Stroustrup is a brilliant man, but let's not forget that he has biases. He isn't happy that Java eclipsed C++ as the primary object-oriented language when it came out. He's attributed it to Sun's marketing, not conceding that it might have improved on C++.
It's a good practice to try and spot biases on the part of any speaker to make sure you're not swallowing someone's view whole. This is one of those cases.
If there are not two independent implementations, language is "Owned" and you are at the mercy of the vendor should he raise prices or can the product.
I don't like that.
EDIT: As often as not, you can count legally forkable codebases as two (the second is yourself).
Aren't all languages owned by a person/company/standards body. The only way I can think of where it isn't really owned by anybody is if the person who made it is anonymous and also public domain
hmm, well Xbox only supports C# for indie games, and no other platform supports it.
obviously the danger is that if you want to do multi platform code, you want the language supported by the most platforms, the more "owned" language is probably going to be supported by less platforms.
the only issue I have is support for the language, and how hard it is to convert from one to the other, for instance I would say c++ to c# is easier than the other way because of memory management.
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Closed 10 years ago.
I'm conducting an interview in 45 min (my second ever!) for a candidate who's pretty junior and states she knows VB and C#. I do not have any experience in either of those languages.
Does anyone have any good simple interview questions for these languages that I can ask that will be informative without being too intimidating?
Note: I'm looking for language-specific ones, and not of the FizzBuzz variety (which I'm already planning on asking).
Related Question
https://stackoverflow.com/questions/70763/good-c-interview-questions-for-a-senior-dev-position
UPDATE: It's over - and thanks everyone! As Jon Skeet says - it's hard to ask questions to which you don't know the answers but I did find that her reaction to the question being asked, even without the answer, was pretty telling and showed me immediately whether or not she was familiar with the concepts being presented.
The problem with asking language-specific questions for a language you don't know yourself is that if any of the answers deviate from the specific ones you've been given here, you won't know if they're right or not. (I humbly suggest that most of the answers given so far suffer from that problem.)
Do you have a laptop available, so you can get them to code and see whether the result is the desired output? If so, FizzBuzz-style questions are a good start, and while you won't be able to judge the idiomatic style of the code you can at least see if it works :)
I find that a useful question to ask is what the candidate likes and dislikes about the language. What would they change if they could?
There are numerous lists on the web.
The C# ones one Mark Wagner's blog are quite good and range from the fairly simple to quite hard so you can go as deep as you like. However, as the commentators have pointed out some of them are in danger of becoming out date (if they're not already) - so use them as a guide.
Look here, maybe you can pick up something not too senior:
Questions every good .NET developer should be able to answer?
Good C# Interview Questions for a Senior Dev Position
I'm no expert on interviewing, so please take this as an opinion rather than gospel.
I'd ask the interviewee to bring in a hundred lines or so of code they've written in each language that accomplishes something interesting. In the interview, let them know what languages you do know, and ask them to review their code with you. Even without knowing the language you should be able to ask questions about various design decisions and determine whether the interviewee is actually comfortable with the language.
I think it is far more important to find out how the candidate thinks than to test their specific knowledge on a topic. For example, they may know C# but do they have the aptitude to learn VB.NET, or F#, or some other language. What makes them tick? Do they get excited by new framework features? What do they do for hobbies? How do they tackle problems? These things are far more important than knowing a language inside and out, especially when even the best developers still rely on the compiler to tell them they screwed up.
Its very dificult to answer your question, because we can list thousands of questions. However here is my abstract idea:
Test whether he knows all OOPs concepts and how it can be acheived in C#/VB.Net
Avoid critical questions as they are juniors.
Test them whether they can differntiate .Net languages from other HLL
Explain some .Net features and ask how they will achive them using C#/VB.Net
(ex: Reflection, Genrics, property)
Make sure that they can very-well pick-up if they given chance to work.
How about asking which strengths and weaknesses do she sees in each language? What would make one more appropriate than the other?
Note that while one could say that she isn't so familiar as to know an answer, that in itself can be a fine answer. Part of what you are wanting to see is their ability to communicate either technical arguments for or against something or an ability to say, "Well, I don't have enough experience to give a thorough answer on this."
I usually interview people for c# developer role. I have found questions at the following URL very helpful for Junior, Mid and Senior developers. You can find a variety of c# interview questions segregated by topic. Here is the URL C# Interview Questions
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Closed 10 years ago.
I've been a "Microsoft developer" ever since I started programming... I started out by learning QBasic then ASP & Visual Basic and finally I moved on to learn VB.NET, ASP.NET and C# which is now my primary language. Still I've always wanted to learn something like Java or C++ to see how what the "other side" is like, and to learn the pros and cons of each platform. The only problem is that I never found the time or opportunity to pick up another language.
My basic understanding is that Java and C# have a lot of similarities as well as a lot of differences. Coming from C# I'm mostly interested in what C# could learn from Java, or put another way, what I'm missing out on.
Nothing, C# based itself on Java :)
prepares to be ridiculously downvoted
Should support Java like Enums, In C# they are just name for numbers !!
I think C# would be better off if they enforced the one public class per file and forced you to put your code files in a directory structure which matches the namespace (i.e. "package"). This is one thing I really like about Java that frustrates me in C#, especially when people start moving .cs files around, and putting multiple public classes in one file.
Personally I would have preferred to use the Java style for properties. I don't like the fact that properties in C# looks exactly like fields and yet have entirely different semantics. By making it clear that properties are really just methods there is no illusion and less risk of mistakes.
Anonymous interface implementation - Java does it, C# does not (yet).
For example:
// C#
interface IRunnable
{
void Run();
}
var runnable = new IRunnable()
{
public void Run()
{
Console.WriteLine("Running...");
// Do your running
}
};
runnable.Run();
checked exceptions
package visibility for submodules. AFAIK you can only have one module per assembly. I mean a group of tightly coupled classes which can see each other but should be hidden from the outside world.
C# obviously learned a great deal from Java, just like Java did from C++. They've traded back and forth in both language features (e.g., Java taking annotations from C#) and ancillary projects (NHibernate, NAnt, Spring.NET, POJO/POCO based development, etc. all have their origins in Java).
But I'm afraid that Java's not advancing anymore now that Sun lost market and people and has been sold to Oracle. I don't see anything coming out of Java or vendors that looks terribly new right now. Java 7 has been a long time coming, and it's catching up with closures and other things.
I think whatever energy is left in language development has passed to dynamic and functional languages.
The only development that I'm aware of that could change that is Rikard Oberg's Qi4J. He's so out there. It's just going to be a long time before it becomes mainstream, if ever.
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Closed 10 years ago.
I'm starting my 2nd class in C# programming through Kaplan online school. I have some limited interaction with the professor and the class online, but nothing like in an actual school. I'm about to go through "Modern Software Development Using C#.NET" by Richard Wiener. It seems the book as a extremely heavy focus on UML (which I don't even really know what that is right now!)
You experinced Csharpers.... any tips to keep in mind as I go through this to keep in perspective how the modern software engineer works outside the classroom?
Any perspectives to share as I start understanding UML and intermediate C# programming?
Some companies will use UML everywhere. Some use it nowhere. I'm not a big fan myself - I prefer ad-hoc diagrams and plenty of other communication (notes on the diagram, actual talking etc).
The good thing about an ad-hoc approach is that you can leave it as vague as you like or make it really detailed. The bad thing about it is you can't generate any code from it - but I've never really liked generating code from UML. (Others swear by it, mind.)
You certainly don't need to know UML to learn C#.
UML would come very close to the end of the list of things that gave me insight into the complex world of programming. I find it very distracting when trying to design something, and too time consuming for real system descriptions. I have always thought it is important and tried to start my project with UML diagram, but it wasn't ever worth it.
The bigger the projects you are working in the more you need a language to speak with, known by all members of the project team - a common language like UML! But you need not to start learning C# with UML.