Information processing system having function of securely protecting confidential information

An information processing system includes a first information processing apparatus and a second information processing apparatus arranged separate from the first information processing apparatus and capable of exchanging a signal with the first information processing apparatus. The first information processing apparatus includes a first key generator for generating a first key, and a first encrypting unit for encrypting data using the first key generated by the first key generator to generate first encrypted information. The second information processing apparatus includes a second key storage unit for storing a second key, and a second encrypting unit for encrypting the first key using the second key stored in the second storage unit to generate second encrypted information. The first information processing apparatus further includes a correlation storage unit for storing the first encrypted information generated by the first encrypting unit and the second encrypted information generated by the second encrypting unit, the first encrypted information being correlated with the second encrypted information.