An encryption information determination section in a communication device negotiates an encryption algorithm to be used for encrypted communications with an encryption information determination section in a network camera, which is a communication counterpart. The techniques include receiving a first message from a source including a first identifier and a second identifier. For each of the plurality of users, the method may include constructing first compilation data that includes information of a first plurality of content elements and wherein the first compilation data constructed for each use may be different. The method includes sizing the at least one extension based on a thermal diffusion length of the resistor.