A method and apparatus of protecting digital content within a domain is provided. if a device registered with a domain withdraws from the domain, a domain key used in the domain before withdrawal of the device is updated to a domain key which cannot be used by the device; and the domain key not exposed to the device is transmitted to a plurality of devices currently registered with the domain so that only the currently registered devices have the most recent domain key. Therefore, devices not registered with the domain and devices which previously registered with the home domain but withdrawn from the home domain can be prevented from using digital content currently shared within the domain. In addition, registered devices that withdraw from the home domain may use digital content legitimately downloaded from the home domain before they withdrew from the domain.