Preventing shortened lifetimes of security keys in a wireless communications security system

摘要

23A wireless communications device has a first security key, a second security key, and established channels. Each established channel has a corresponding security count value, and utilizes a security key. At least one of the established channels utilizes the first security key. The second security key is assigned to a new channel. A first set is then used to obtain a first value. The first set has only security count values of all the established channels that utilize the second key. The first value is at least as great as the x most significant bits (MSB_x) of the greatest value in the first set. The MSB_x of the initial security count value for the new channel is set equal to the first value. If the first set is empty, then the initial security count is set to zero.