A method for securely transmitting information to a content server and an authorized user of a communication device , the method comprising: a content owner device obtaining a first content item ; the content owner device obtaining a first tag associated with the first content item , wherein the first tag comprises a set of one or more keywords associated with the first content item and a first content item identifier for identifying the first content item ; the content owner device obtaining a first content key for said first content item ; the content owner device encrypting the first content item using the first content key, thereby producing a first encrypted content item; the content owner device transmitting information to the content server , the information comprising the first encrypted content item and the first tag, and the method being characterized by : the content owner device deriving a first derived key using at least the first tag, comprising the set of one or more keywords associated with the first content item and the first content item identifier, and a key derivation function; the content owner device encrypting the first content key using the first derived key, thereby producing a first encrypted content key; the content owner device transmitting to the content server the first encrypted content key; the content owner device receiving from the communication device of the user the first content item identifier for identifying the first content item ; the content owner device , in response to receiving the first content item identifier, determining whether or not the user is authorized to obtain the first content item identified by the first content item identifier; and the content owner device , in response to determining that the user is authorized to obtain the first content item , transmitting to the communication device of the user the first derived key for decrypting the first encrypted content item. a content owner device obtaining a first content item ; the content owner device obtaining a first tag associated with the first content item , wherein the first tag comprises a set of one or more keywords associated with the first content item and a first content item identifier for identifying the first content item ; the content owner device obtaining a first content key for said first content item ; the content owner device encrypting the first content item using the first content key, thereby producing a first encrypted content item; the content owner device transmitting information to the content server , the information comprising the first encrypted content item and the first tag, the content owner device deriving a first derived key using at least the first tag, comprising the set of one or more keywords associated with the first content item and the first content item identifier, and a key derivation function; the content owner device encrypting the first content key using the first derived key, thereby producing a first encrypted content key; the content owner device transmitting to the content server the first encrypted content key; the content owner device receiving from the communication device of the user the first content item identifier for identifying the first content item ; the content owner device , in response to receiving the first content item identifier, determining whether or not the user is authorized to obtain the first content item identified by the first content item identifier; and the content owner device , in response to determining that the user is authorized to obtain the first content item , transmitting to the communication device of the user the first derived key for decrypting the first encrypted content item. <EOS>