Posted December 31, 20213 yr Sean's KeyGenMe - Simple Tricks I coded a keygenme, simple tricks. I hope you enjoy your time trying to solve this! File Information Submitter lovejoy226 Submitted 12/31/2021 Category KeygenMe View File
January 1, 20223 yr Example keys: Spoiler washi: B604404A000831E195B4291B3F35A23F5B6B7592 tuts4you: DD6850E979CB255113546C9F0045C863B63CE83100497814DD6850E900497814 Approach: Spoiler Problem with this keygenme is that the input serial key is compared to the correct serial key directly using string comparison. This means the app generates a correct serial itself, which means the "only" thing to do is finding this algorithm in a decompiler and copy it for a keygen. Open in Ghidra, notice it's an MFC app so no "obvious" entrypoint Run app, notice app shows a message box after a bad input was put in. XRef for MessageBoxW calls and find function FUN_004019b0 which contains both the serial generation algorithm , as well as the two good and bad boy messagebox calls. Algorithm is pretty simple: For every character c, compute c^5 * j, where j is any number between 1 and 0x91. The results are concatenated using an uppercase hex format. Final string is reversed. If any of these j's work, then it is a valid serial. For a keygen, just pick a random j and do exactly the same to produce a serial: keygen.py Edited January 1, 20223 yr by Washi
January 2, 20223 yr Author Washi. Conratulations. You fully analyzed the algorithm of my keygenme. Thank you for your attention. regards. sean.
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