Integrity of my exe

Hi,

I need my program to check that its own integrity is ok. For example: if someone used a hexadecimal editor to alter something in the exe, the program shouldn't start or even better: should start, display a messagebox that the integrity is not ok and then shutdown.

How to do this?

Thanks,

Ray

Bundle the MD5 checksum with the application ?

Use CRC32!
Here's some easy example:
Read ur EXE
For first byte, merge it with the subsequent byte to produce
a 32bit(4 bytes) long data, and for subsequent bytes,
for each byte merge it with the previous 32bit data and
produce a new 32bit data

By mean of merge, you can use complex algorithms to
encrypt that two bytes together to produce the 32bit data