A method and apparatus for time-based charging for viewing content from a broadcast-multicast service (BCMCS) at a mobile station of a wireless communication system is disclosed. A count value (SKCount) is determined based upon the number of generated short-term keys (SK) that are used to decrypt particular content from the BCMCS. The amount of time the particular content is viewed at the mobile station may be determined as a function of the count value (SKCount) and the period (SKPeriod) between the generation of the short-term keys. This provides information about a user's actual content view time since the short-term key is needed to view the particular content broadcast to the mobile station.