An information processing apparatus includes a shared information generation unit for generating shared information via a network, a communication unit configured to receive a message, a shared information verification unit configured to compare shared information in the message with the information generated by the shared information generation unit, and verify validity of the shared information in the message based on the comparison, a security code generation unit for generating a security code based on the shared information, a security code verification unit configured to compare a security code in the message with the security code generated by the security code generation unit, and verify correctness of the shared information in the message based on the comparison, and a processing determination control unit configured to determine normality of the message on the based on the verification by the shared information verification unit and the verification by the security code verification unit.