Serial String Comparison That Helps Prevent Crackin

Category:
String Manipulation
Type:
Snippets
Difficulty:
Beginning
Author:
Jeremy Loper

Version Compatibility: Visual Basic 6, Visual Basic 5

More information:
Crackers will enter a fake serial number into a piece of shareware and set their debugger to break on different API calls. They search the memory registers for the real serial being compared to their fake serial.

Ex.
mov esi, Al
cmp eax, esi <---Compare Two Operands
je 00404531

When they find that comparison they find the real serial for their name. This will compare the serials a character at a time, this may cause a cracker to keep looking for the comparison.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:

Code: