Method for playing digital contents protected with a DRM (digital right management) scheme and corresponding system

1. A method for playing digital contents protected by a DRM scheme, the protected digital contents being downloaded by a user device from a media server in the form of protected segments, the method comprising:

executing a DRM proxy inside the user device, the DRM proxy interfacing the media server and a player coupled to the user device, the player being configured to implement the HTTP Live Streaming protocol (HLS) and HLS encryption;

executing an HLS server in the DRM proxy;

registering the DRM proxy to handle HTTP requests received by the user device;

producing by the DRM proxy a playlist in HLS format including a list of segment URLs locating the individual protected segments, the segment URLs being formatted with a host name or IP address assigned to the user device;

processing the playlist in the player, whereby the player successively issues a request for each segment URL in the playlist, and each segment URL is directed to the HLS server of the DRM proxy;

including in the playlist, for each segment, a key URL being formatted with the host name or IP address assigned to the user device, whereby the player issues a request for each key URL before each segment URL, and each key URL is directed to the HLS server of the DRM proxy;

in the DRM proxy, producing a key for each segment and, in response to a key URL request, returning the corresponding key to the player;

in the DRM proxy, acquiring a license to access the protected segment identified by a current segment URL request;

decrypting the protected segment in the DRM proxy based on the license; and

in the DRM proxy, re-encrypting each decrypted segment with the corresponding key and, in response to a segment URL request, returning the corresponding re-encrypted segment to the player.

2. The method according to claim 1 , wherein the player is a native player of the user device.

3. The method according to claim 1 , wherein the player is an AirPlay enabled device connected to a same local network as the user device.

4. A non-transitory computer readable storage medium storing instructions which, when executed on a processor, perform the method according to claim 1 .

5. A user device for playing digital contents protected by a DRM scheme and downloaded from a media server in the form of protected segments, comprising:

a network connection to a player configured to implement the HTTP Live Streaming protocol (HLS) and HLS encryption;

a DRM proxy interfacing the media server and the player connection, the DRM proxy configured to

run an HLS server;

register itself to handle HTTP requests received by the user device;

produce a playlist in HLS format including a list of URLs locating the individual protected segments, the segment URLs being formatted with a host name or IP address assigned to the user device;

including in the playlist, for each segment, a key URL being formatted with the host name or IP address assigned to the user device, whereby the player issues a request for each key URL before each segment URL, and each key URL is directed to the HLS server of the DRM proxy;

producing a key for each segment and, in response to a key URL request, returning the corresponding key to the player;

send the playlist to the player through the network connection;

receive a segment URL request from the player on the network connection;

acquire a license to access the protected segment identified by the segment URL request;

decrypt the protected segment based on the license; and

re-encrypt each decrypted segment with the corresponding key and, in response to a segment URL request, return the corresponding re-encrypted segment to the player.

6. The device according to claim 5 , wherein the player is a native player of the user device.

7. The device according to claim 5 , wherein the player is an AirPlay enabled device connected to a same local network as the user device.