It's also worth noting that word verification DRM can be
trivially broken. Like, under 15 minutes by someone who isn't experienced. It never involves any kind of encryption, just a pure challenge-response. You run a memory debugger on the application, get a breakpoint on the challenge, bypass the challenge verification, ta-da.
Actually, pretty much every DRM pre-mid 90s consisted of x86 assembly in the following manner:
lda drmVerificationValue
cmp expectedVerificationValue
beq gameRoutine
jmp failRoutine
oh no, how ever will we remove this awful DRM?
Half the DRM cracks before that point are literally find-replace of 2-4 ASM instructions with NOP.