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. net zero foundation reverse course lesson 2 (get registration code)

With the foundation of the first lesson, do you want to try your skill, then let's try it!
This lesson, we want to use the knowledge of the first lesson, to obtain a software registration code!
The software provided by him in the second session is based on the software of constant speed So don't worry about the function. Why can't you use it.

Software is a "IP search tool", there are registration items, we will take this software to get the registration code!
Note: (it is also a primary software, and does not involve various elements that interfere with novice learning.)
Here is a screenshot of the registration interface

After registration, there will be a prompt. No matter what he prompts, we also know what to do, right? Of course, the search results of "dny / name" in the first class may not be correct, because you can't do so many search results according to the slash of "spname", which may cause you to miss too many search results.
Double click on the string just now, it's easy to find the second one!  

The judgment basis is actually very simple. Look at the right part of my frame, it represents which file the string comes from. Obviously, only the second of the three results is from our courseware. Of course, if you are a novice, you may not be able to filter all the strings from a DLL file.

After double-click, we also find the relevant judgment according to the steps in Lesson 1. If you want to blow up, you can directly modify the judgment of 34 lines.

But today we don't blow up. What we play is to find out the registration code.

Let's read the logic of this registration:

Line 22, the contents of the first edit box are first deleted, and then the contents encrypted by rsaencrypt() function are assigned to the variable text

Text2, and then delete the first and last line of the variable

Line 24-33, judge whether the contents of text and text2 are empty. If yes, an error will be reported in the pop-up window

Lines 34-41, judge whether text and text2 are equal. If they are equal, it proves that the activation code is correct. Then add the word "registered" to the title of the main interface. If not, an error will be reported in the pop-up window

Therefore, if you want to explode in this program, if you want to activate directly without filling in two edit boxes, you can delete the contents of 24-33 lines, and then modify the judgment conditions of 34 lines. You can also directly clear the contents of 22-41 lines and keep only 36-37 lines. In this way, you can directly complete the activation when you click the register button on the main program.

If I have a few questions about the planet, please ask me some questions.

Then we know from the code that text and text2 should be compared, that is, when we fill in the content in the second edit box, which is encrypted by the rsaencrypt() function in the first edit box, we can complete the registration.

On line 23, right-click to add a breakpoint. You can also interpret breakpoint as "pause", that is, tell dnspy to pause when the program runs here (at this time, the marked line has not been executed).

Click start to run the program, and the registration window is in file -- > register

Now enter the registration information (remember the user name, write the registration code casually) and click Register.

You will find that the program is not responding. We have a yellow arrow in the middle of the red dot before the breakpoint in snspy, which means that the software has been executed here.

Back to dnspy, notice the text and text2 variables in the local variables window below

Click F10 to see

We found that text has been assigned. Yes, this value is the registration code!

Right click the value of text and copy the value

Then click the little red dot in front of the lower breakpoint code to cancel the breakpoint.

Click continue, or press F5 to let the program that we have broken point continue to run

It doesn't matter if there is an error

Paste the value we copied into the second edit box

Sign up ~ and you'll be beaten in the face

What's wrong?

Dnspy will automatically add a pair of quotation marks when copying text type values, so we can paste the copied values into the second edit box and delete the quotation marks ourselves.

The software becomes registered.

Congratulations, you have learned to blow up and get the registration code through lesson 1 and lesson 2!


Finally, the role of F10 is explained

Look at this picture. The buttons are as follows:

Continue: continue to run the program unless the next breakpoint is encountered or the next operation is waiting

Pause: pause to a breakpoint or operation waiting point

Stop: end running program

Restart: rerun the program to a breakpoint or wait for an operation

Show next statement: used to preview the next statement to be executed

Statement by statement: execute one line statement at a time. If a function call is encountered, it will enter the function

Step by step: execute a line of statements each time. When a function is encountered, it will not enter the function and execute the function call as a statement

Call out: when you enter a function, jump out allows you to directly execute the remaining statements in the function until you return to the following statement when the function is called

Search assembly: we just learned about it last time~

A quote from shark Heng:

Usually, a lot of courses are related to the theory of the novice. This is not my tutorial charm, my tutorial is to let novice quickly get interested, so that novices have the opportunity to learn theory and basic knowledge. As long as he has an interest, it's easy to say anything else. He will learn theory and basic knowledge by himself. If you are not interested, the theory and basic knowledge are both lullaby.


Courseware: https://articles.zsxq.com/id_ wixv8nql022h.html


 
 

Software unable to download / install / other computer problems, plus Penguin Group: 709531763

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  Computer course for College Students
Article title: reverse course of. Net zero foundation - Lesson 2 (obtaining registration code)
Author: Mu Ruoxi
Release date: March 26, 2019 05:30 Tuesday Mu Ruoxi blog
Link to this article: https://www.muruoxi.com/jiaocheng/4040.html
 
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2 comments

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  1. sofa
    Flying snow   

    Take out the code in rsaencrypt() and write a registration machine

    12:30 am, March 27, 2019   comment
    • Mu Ruoxi   

      yes

      12:00 pm, March 27, 2019   comment

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