I used to have this C source that I could embed in a program, and it would tell me if the software had been tampered with at runtime. I've lost/mislaid/whatever the source, and I was wondering if anyone had anything that would do the same thing. As I recall, it calculated a simple CRC and embedded it into the .EXE file (it was written for MS-DOS).
It doesn't need to be cryptographically secure - I just need to check to see if the executable has been corrupted. I've leafed through alt.sources and comp.sources.*.
You are aware that there is a generic attack against all such defenses - aren't you? It has been published for 7+ years. For details see: A Short Course on Computer Viruses - Wiley and Sons - 94 -- -> See: Info-Sec Heaven at URL http://all.net Management Analytics - 216-686-0090 - PO Box 1480, Hudson, OH 44236