Download the program:
Link: https: //pan.baidu.com/s/1Wh033pBJObAPDtK4x-ZBYg
extraction code: kjq3
copy the contents of this open Baidu network disk phone App, the operation more convenient oh
[CrackMe] CrackMe on a file and read operations
1. First, let's open the file, enter nothing, registration error is displayed, and a look ignorant force ...
2. After that, we use the OD open the program jumps to the interface pauses, then back to the execution of the main flow of the program through the stack.
3. Review the above, it seems that reads a file named "KeyFile.dat" if the open fails to perform here.
4. We direct use IDA tools to analyze this document
5. We proceed correctly process, we found to have the number of bytes read requirements, must be not less than 10h (16) months.
6. let us resolve implementation process:
As shown below, therefore, we want to ensure successful registration, you must ensure that the total number of characters not less than 16 in KeyFile.dat file and format G appears no less than eight, so to be successful.
The above requirements, we construct CrackMe.exe documents in the directory, all directly filled with 'G'. After running the program, the program found the successful break.
8. problem solving harvest: the essence of the program is to go break the correct procedure, which found that the condition is not satisfied then go back to their meet, do not fall into the wrong logic can not get out! ! !