its not quite an encryption, also you do know if you can make a bios you can send it too NVidia for verification that it will not damage the gpu and they will certify it if its good. btw that flashing program can remove the protection from the bios and put it back on as per what the readme says for the flashing program

and just came across this NVidia gpu bios editor. looks like its got some pretty advanced settings to play with
http://nvidia-bios-editor.en.lo4d.com/