The present invention provides an encryption key distribution method for service protection and content protection in a mobile broadcasting system, and a system for the same. The encryption key distribution method according to the present invention includes the steps of: a network generating a first encryption key when a broadcasting service starts providing the service thereof to a terminal; the network transmitting a long-term key message containing the first encryption key generated in the previous step to the terminal; the network generating a second encryption key prior to the expiration of the lifetime of the first encryption key; and the network transmitting the long-term key message containing the second encryption key generated in the previous step to the terminal.