.DM File Extension

File (often audio) that has been encoded with DRM (Digital Rights Management) copy-protection; used by some cell phones for ringtones and other media clips, but can also be used for digitally signed mobile applications; can only be opened using an authorized cell phone.

Normally DM files are installed in the background using a mobile phone download and installation service such as the online Nokia Ovi Store. However, sometimes users download DM files manually and save them to the desktop. For example, a user could save a Nokia Ovi Store .SIS or .SISX application file as a .SIS.DM or .SISX.DM file.

DM files can also be created with the DRM Packager Tool for Sony Ericsson phones.

A DM file is an encrypted file created by the Gallery app included with select LG mobile phones, such as the G4 and G5. It contains a video or image that has been encrypted by the user to prevent the content from being viewed by other users. DM files can only be viewed using the Gallery app included with the phone and the correct PIN number or fingerprint.

LG users may create DM files when opening an image or video, such as a .JPG, .GIF, or .MOV file, in the Gallery app. While viewing the image, the user can tap "Lock" in the top-right menu and set a PIN number to protect the file.