Yup, I think the bad information is what the PlayStation ones use. Basically CDROM/DVD specs include a lot or error checking (like 8n10b encoding). The intent is that scratches will remove some data, and it's usually not enough to impact anything.

Sony exploited this, they put intentional low level damage in the data. Damage that any standards compliant drive would assume is a simple scratch and correct. And in fact, the vast majority were unable of doing otherwise as they had dedicated chips for making these corrections. Sony then just searched the disk for specific, predefined errors, and they could do it because they had custom chips that reported the errors. And they were able to say if the disk wasn't damaged in the right spots then it wasn't legit.