Is there any solution to get back DRM keys for SGP511 wifi with marshmallows 6.0.1?

As I am new to the android environment, I didn't back up the DRM keys before unlock the bootloader. Is there any solution to get it back for SGP511 xperia z2 tablet wifi with marshmallows 6.0.1 and 23.5.A.0.575? Thank you so much for the guide.