FIELD: IT security.
SUBSTANCE: authentication request is repeatedly received, containing encrypted information obtained by encryption using a cryptographic key and transmitted from the device for transmitting an information authentication request, during the authentication period. Encrypted information is decrypted to obtain decrypted information. It is determined whether the device for transmitting the information authentication request is legitimate using a plurality of authentication requests received during the authentication period and containing encrypted information that has been decrypted. A determination result is output at the stage of determining whether the device for transmitting the information authentication request is, in which the device for transmitting the information authentication request, which is legitimate, transmits a plurality of authentication requests respectively containing encrypted information obtained by encrypting a plurality of pieces of unique information generated by the device for transmitting an authentication request information during the authentication period.
EFFECT: increased security of information authentication.
14 cl, 10 dwg
