.dcf

Media file encoded with DRM (Digital Rights Management) copy-protection; used by some cell phones for saving protected ringtones, pictures, videos, and other media clips; similar to a .DM file, but the rights object, which allows the encrypted data to be played back, is contained in a separate file.

Because DCF files are saved in a protected or "locked" format, they can typically only be opened using an authorized DRM-compatible cell phone.