1. First of all, to achieve this target to make DRM work, a Digital Program Authorization Center (also known as DRM server) must be established first.
2. Then it requires to encoding the digital content like videos and audio files with a public key and the URL of the DRM Server on the head of media files. The public key is used to prevent the file from editing.3. Third, when customers buy a DRM file, it will add two private keys, one is saved on the DRM server and the other one with customer info is saved on the downloaded file. With both private keys, the DRM system can verify and authorize the file to be played normally. This looks like a secret handshake between the download file and the DRM server.