The present embodiments relate to a communication system, communication method, information processor, method, device, program, and recording medium which permit plural algorithms to be treated and which can impart expansibility to communications.A capability list stores a capability list in which capabilities regarding algorithms for encryption and decryption treated by a reader/writer are described. Similarly, a capability list stores a capability list in which capabilities regarding algorithms for encryption and decryption treated by an IC card are described. The reader/writer and the IC card exchange their mutual capability lists, select algorithms capable of securing a security level according to the importance of the data sent and received, and perform communications based on the selected algorithms. The present embodiments can be applied, for example, to a device that performs communications by the NFCIP method.