Each disc will have a contactless tag that can be read by the console, similar to NFC/RFID.
Reads the patent (via EuroGamer): "When the game is to be played, the reproduction device conveys the disc ID and a player ID to the use permission tag. The use permission tag stores the terms of use of the game and determines whether a combination of the disc ID and the player ID conveyed from the reproduction device fulfills the terms of use or not."
It is clear that Sony wants to eliminate the used game market, where it doesn't see a cent.
"As a result [of the patented idea], the dealing of electronic content in second-hand markets is suppressed, which in turn supports the redistribution of part of proceeds from sales of the electronic content to the developers."