Authentication method, authentication apparatus, and computer product

1. A method of authenticating a subject device to be authenticated, comprising:

acquiring current authentication information that is created using an arbitrary value, and that is used for a current authentication process, from the subject device;

acquiring encryption information that is the arbitrary value encrypted using next authentication information as an encryption key, from the subject device;

receiving first transmission information that is expressed as the next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication process, and second transmission information in which the arbitrary value is hidden using the next authentication information, from the subject device;

calculating the next authentication information based on the first transmission information and the current authentication information;

calculating the arbitrary value based on calculated next authentication information and the second transmission information; and

determining whether to authenticate the subject device based on a calculated arbitrary value and the current authentication information,

wherein the acquiring includes acquiring the current authentication information that is created by performing, two times, an operation using a one-way function on the arbitrary value, and

wherein the determining includes

decrypting the encryption information using the next authentication information;

determining whether to authenticate the subject device based on decrypted encryption information;

performing, two times, the operation using the one-way function on the calculated arbitrary value; and

determining whether to authenticate the subject device based on whether a value obtained by performing, two times, the operation using the one-way function on the calculated arbitrary value is identical to the current authentication information.

2. The method according to claim 1 , wherein

the acquiring includes acquiring the current authentication information that is created by performing an operation using a one-way function on an arbitrary value, and

the determining includes

performing the operation using the one-way function on the calculated arbitrary value; and

determining whether a value obtained by performing the operation using the one-way function on the calculated arbitrary value is identical to the current authentication information.

3. The method according to claim 1 , wherein

the receiving includes receiving a value obtained by performing an operation using a mask function on the next authentication information and the current authentication information, as the first transmission information, and a value obtained by performing the operation using the mask function on the arbitrary value and the next authentication information, as the second transmission information,

the calculating the next authentication information includes calculating the next authentication information by performing the operation using the mask function on the first transmission information and the current authentication information, and

the calculating the arbitrary value includes calculating the arbitrary value by performing the operation using the mask function on the calculated next authentication information and the second transmission information.

4. The method according to claim 1 , further comprising

acquiring an authentication key from the subject device, wherein the authentication key is unique to the subject device, wherein

the receiving includes receiving a value in which the arbitrary value is hidden by a value obtained by performing an operation using the authentication key on the next authentication information as the second transmission information, and

the calculating the arbitrary value includes calculating the arbitrary value based on the authentication key, the calculated next authentication information, and the second transmission information.

5. The method according to claim 1 , further comprising

acquiring an authentication key from the subject device, wherein the authentication key is unique to the subject device, wherein

the receiving includes receiving a value in which a value obtained by performing an operation using the authentication key on the next authentication information is hidden using the current authentication information, as the first transmission information, and

the calculating the next authentication information includes calculating the next authentication information based on the authentication key, the first transmission information, and the current authentication information.

6. A method of requesting an authentication to an authenticating apparatus from a subject device to be authenticated, comprising:

creating current authentication information that is used for a current authentication process, using an arbitrary value;

acquiring encryption information that is the arbitrary value encrypted using next authentication information as an encryption key, from the subject device;

delivering the current authentication information and the encryption information to the authenticating apparatus;

creating first transmission information that is expressed as the next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication process;

creating second transmission information in which the arbitrary value is hidden using the next authentication information;

transmitting the first transmission information and the second transmission information to the authenticating apparatus,

wherein the creating current authentication information includes creating the current authentication information by performing, two times, an operation using a one-way function on the arbitrary value.

7. The method according to claim 6 , wherein

the creating current authentication information includes creating the current authentication information by performing an operation using a one-way function.

8. The method according to claim 6 , wherein

the creating the first transmission information includes performing an operation using a mask function on the next authentication information and the current authentication information, and

the creating the second transmission information includes creating the second transmission information by performing the operation using the mask function on the arbitrary value and the next authentication information.

9. The method according to claim 6 , further comprising:

creating an authentication key that is unique to a subject device to be authenticated; and

delivering the authentication key to the authenticating apparatus, wherein

the creating second transmission information includes

performing an operation using the authentication key on the next authentication information; and

creating the second transmission information in which the arbitrary value is hidden by a value obtained by performing the operation using the authentication key on the next authentication information.

10. The method according to claim 6 , further comprising:

creating an authentication key that is unique to a subject device to be authenticated; and

delivering the authentication key to the authenticating apparatus, wherein

the creating the first transmission information includes

performing an operation using the authentication key on the next authentication information; and

creating the first authentication information in which a value obtained by performing the operation using the authentication key is hidden using the current authentication information.

11. A non-transitory computer-readable recording medium that stores therein a computer program for authenticating a subject device to be authenticated, the computer program making a computer execute:

acquiring current authentication information that is created using an arbitrary value, and that is used for a current authentication process, from the subject device;

acquiring encryption information that is the arbitrary value encrypted using next authentication information as an encryption key, from the subject device;

receiving first transmission information that is expressed as the next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication process, and second transmission information in which the arbitrary value is hidden using the next authentication information, from the subject device;

calculating the next authentication information based on the first transmission information and the current authentication information;

calculating the arbitrary value based on calculated next authentication information and the second transmission information; and

determining whether to authenticate the subject device based on a calculated arbitrary value and the current authentication information,

wherein the acquiring includes acquiring the current authentication information that is created by performing, two times, an operation using a one-way function on the arbitrary value, and

wherein the determining includes

decrypting the encryption information using the next authentication information;

determining whether to authenticate the subject device based on decrypted encryption information: and

performing, two times, the operation using the one-way function on the calculated arbitrary value; and

determining whether to authenticate the subject device based on whether a value obtained by performing, two times, the operation using the one-way function on the calculated arbitrary value is identical to the current authentication information.

12. A non-transitory computer-readable recording medium that stores therein a computer program for requesting an authentication to an authenticating apparatus from a subject device to be authenticated, the computer program making a computer execute:

creating current authentication information that is used for a current authentication process, using an arbitrary value;

acquiring encryption information that is the arbitrary value encrypted using next authentication information as an encryption key, from the subject device;

delivering the current authentication information and the encryption information to the authenticating apparatus;

creating first transmission information that is expressed as next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication process;

creating second transmission information in which the arbitrary value is hidden using the next authentication information; and

transmitting the first transmission information and the second transmission information to the authenticating apparatus,

wherein the creating current authentication information includes creating the current authentication information by performing, two times, an operation using a one-way function on the arbitrary value.

13. An authentication apparatus comprising:

a first acquiring unit configured to acquire, from a subject device to be authenticated, current authentication information that is created using an arbitrary value and that is used for a current authentication process, and encryption information that is the arbitrary value encrypted using next authentication information as an encryption key, from the subject device;

a receiving unit configured to receive, via a network interface, first transmission information that is expressed as next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication, and second transmission information in which the arbitrary value is hidden using the next authentication information, from the subject device;

a first calculating unit configured to calculate the next authentication information based on the first transmission information and the current authentication information;

a second calculating unit configured to calculate the arbitrary value based on calculated next authentication information and the second transmission information; and

a determining unit configured to determine whether to authenticate the subject device based on a calculated arbitrary value and the current authentication information,

wherein the acquiring includes acquiring the current authentication information that is created by performing, two times, an operation using a one-way function on the arbitrary value, and

wherein the determining includes

decrypting the encryption information using the next authentication information;

determining whether to authenticate the subject device based on decrypted encryption information; and

performing, two times, the operation using the one-way function on the calculated arbitrary value; and

determining whether to authenticate the subject device based on whether a value obtained by performing, two times, the operation using the one-way function on the calculated arbitrary value is identical to the current authentication information.

14. An authentication apparatus comprising:

a creating unit configured to:

create current authentication information that is used for a current authentication process, using an arbitrary value;

create first transmission information that is expressed as next authentication information exclusive-OR the current authentication information, the next authentication information being used for a next authentication process;

create second transmission information in which the arbitrary value is hidden using the next authentication information; and

acquire encryption information that is the arbitrary value encrypted using the next authentication information as an encryption key;

a delivering unit configured to deliver the current authentication information and the encryption information to an authenticating apparatus that authenticates the authentication apparatus; and

a transmitting unit configured to transmit, via a network interface, the first transmission information and the second transmission information to the authenticating apparatus,

wherein the creating current authentication information includes creating the current authentication information by performing, two times, an operation using a one-way function on the arbitrary value.