Apparatus for generating secret information on basis of ring oscillator architecture and method of same

1. An apparatus for generating secret information on the basis of a ring oscillator, the apparatus comprising:

multiple hardware physically unclonable function (PUF) information generation units each including at least one ring oscillator cell configured to generate PUF information;

a phase checking unit configured to

cross-check phases for multiple pieces of the PUF information that are output from the multiple PUF information generation units, respectively, and

detect a phase of a clock signal generated through each of the at least one ring oscillator cell; and

a secret key generation unit configured to output secret key information based on a result of comparing the multiple phases received from the phase checking unit;

wherein the at least one ring oscillator cell comprises: a flip-flop element configured to receive an oscillator enable signal and a system clock signal;

an AND gate;

an odd number of inverter cells connected to an output terminal of the AND gate in series; and

a divider configured to divide a clock of a last inverter cell of the odd number of inverter cells by two,

wherein an output of the flip-flop element is connected to a first input of the AND gate, and

an output of the last inverter cell is connected to a second input of the AND gate; and

wherein the phase checking unit and the secret key generating unit are integrated in a hardware component.

2. The apparatus of claim 1 , wherein the multiple PUF information generation units comprise:

a first PUF information generation unit including the at least one ring oscillator cell and configured to generate first PUF information; and

a second PUF information generation unit including the at least one ring oscillator cell and configured configured to generate to generate second PUF information.

3. The apparatus of claim 2 , wherein the phase checking unit comprises:

a first phase processing unit configured to receive the first PUF information output from the first PUF information generation unit as a target signal, receive the second PUF information output from the second PUF information generation unit as a reference signal, and detect a phase between the reference signal and the target signal for outputting; and

a second phase processing unit configured to receive the first PUF information output from the first PUF information generation unit as a reference signal, receive the second PUF information output from the second PUF information generation unit as a target signal, and detect a phase between the reference signal and the target signal for outputting.

4. The apparatus of claim 3 , wherein the secret key generation unit comprises:

a first counter configured to count a first phase value output from the first phase processing unit;

a second counter configured to count a second phase value output from the second phase processing unit; and

a comparator configured to compare outputs of the first and the second counters.

5. The apparatus of claim 1 , wherein the phase checking unit is configured to receive the multiple pieces of the PUF information as a reference signal and a target signal, and to detect a phase between the reference signal and the target signal for outputting.

6. The apparatus of claim 1 , wherein the secret key generation unit comprises:

multiple counters configured to count the multiple phases; and

a comparator configured to compare output values of the multiple counters.

7. A method of generating secret information on the basis of a ring oscillator, the method comprising:

generating and outputting, by multiple hardware physically unclonable function (PUF) information generation units each including at least one ring oscillator cell, PUF information;

checking, by a phase checking unit, phases for multiple pieces of the PUF information that are output from the multiple PUF information generation units;

detecting a phase of a clock signal generated through each ring oscillator cell; and

generating, by a secret key generation unit, secret key information by comparing values that result from counting multiple phases corresponding to the multiple pieces of the PUF information;

wherein the at least one ring oscillator cell comprises: a flip-flop element configured to receive an oscillator enable signal and a system clock signal;

an AND gate;

an odd number of inverter cells connected to an output terminal of the AND gate in series; and

a divider configured to divide a clock of a last inverter cell of the odd number of inverter cells by two;

wherein an output of the flip-flop element is connected to a first input of the AND gate, and

an output of the last inverter cell is connected to a second input of the AND gate;

and wherein the phase checking unit and the secret key generating unit are integrated in a hardware component.

8. The method of claim 7 , wherein the generating and the outputting of the PUF information comprises:

generating first PUF information by using the at least one ring oscillator cell; and

generating second PUF information by using the at least one ring oscillator cell.

9. The method of claim 7 , wherein the checking of the phases comprises:

receiving the multiple pieces of the PUF information as a reference signal and a target signal, and detecting a phase between the reference signal and the target signal.

10. The method of claim 7 , wherein the generating of the secret key information comprises:

counting the multiple phases; and

generating the secret key information by comparing values that result from the counting.