DVD43 is a simple CSS decrypter that runs in the background, essentially like a driver. It allows copying programs like 1Click to see the DVD as having no CSS encryption. Version 3.90 is popular with some 1Click users right now because the combination of 1Click's CPRx, which removes Arcoos and other exotic protections, and DVD43 allows the backup of virtually any disk. Other 1Click users continue to use AnyDVD, which works in the background like DVD43, but handles the exotic protection schemes itself. That makes it usable with programs like Recode and CloneDVDII, as well.