Cross certification method and certifying device for providing the method

A non-transitory computer readable medium comprising instructions configured to cause a processor to perform a process, the process comprising:

• responsive to determining that first identification information of an electronic device and second identification information of a certifying device correspond to each other, encrypting the second identification information with a first encryption algorithm to generate an encrypted certification message;
• transmitting the encrypted certification message to the electronic device to request a second certification;
• receiving a first random element from the electronic device in response to the request for the second certification;
• inputting an initial vector and the second identification information to a random element generating algorithm to generate a second random element;
• comparing the first random element with the second random element;
• and
• determining whether to approve the second certification according to a result of the comparison.

A cross certification method for an electronic device to perform a cross certification with a certifying device including same certification information, the method comprising:

• transmitting first identification information to the certifying device to request a first certification;
• receiving an encrypted certification message from the certifying device for a second certification;
• encrypting the first identification information of the electronic device using an encryption algorithm to generate an encrypted device message;
• comparing the received encrypted certification message with the encrypted device message to verify the encrypted certification message;
• and
• determine whether the received encrypted certification message and the encrypted device message correspond to each other.