Patent ID: 8126149

Claim:
A communication apparatus comprising: a communication unit having a power-saving function configured to initiate a transition to a power-saving communication state wherein the communication apparatus communicates with a first device; an encryption unit configured to transition to a first encrypted communication state where a predetermined encryption key is used to communicate with the first device when the communication unit initiates the transition to the power-saving communication state and to transition to a second encrypted communication state where a different encryption key from the predetermined encryption key is used or an unencrypted communication state when the communication unit terminates the power-saving communication state, wherein the predetermined encryption key is not used before transitioning to the power-saving communication state; and an address reassignment unit configured to broadcast a message for confirming overlap of a network address of the communication apparatus with a network address of a second device and to reassign a network address of the communication apparatus in a case where the encryption unit transitions to the second encrypted communication state or to the unencrypted communication state from the first encrypted communication state when the communication unit terminates the power-saving communication state, wherein the communication unit communicates with the first device in the second encrypted communication state or the unencrypted communication state after the reassignment of the network address of the communication apparatus is completed.