What I recall from the old days: it was indeed possible to detect Softice, through various ways, for instance simply trying to use its own API (through int3 as

What I recall from the old days: it was indeed possible to detect Softice, through various ways, for instance simply trying to use its own API (through int3 as well having registers set to special magic values). Another trick to detect breakpoints as an anti-debugging measure was to compute a key over the block of memory that was to be protected. Any int3s in there would give a different output. A countermeasure was to use "memory breakpoints" which work via the x86 debug registers: https://en.wikipedia.org/wiki/X86_debug_register https://en.wikipedia.org/wiki/X86_debug_register