Systems and methods for detecting replay attacks to an authentication system
A REE can approve or deny authentication based on a sensor output signal and a secure element (SE) operatively coupled to the REE can detect a replay attack. A feature extractor produces a feature vector from the sensor output signal. The feature vector can be used to authenticate a user. Detecting the replay attack can include storing previous feature vectors, sending a security breached signal to the REE in response to determining that the feature vector equals one of the previous feature vectors, and storing the feature vector as one of the previous feature vectors. The REE can deny authentication in response to receiving the security breached signal.
1 . A system comprising:
a rich execution environment (REE) configured to approve or deny authentication based on a sensor output signal;
a feature extractor configured to produce a feature vector from the sensor output signal; and
a secure element operatively coupled to the REE and configured to perform an authentication operation and to detect a replay attack based on the feature vector, wherein detecting the replay attack includes:
when the feature vector matches one of a plurality of feature templates, each feature template associated with one of a plurality of authorized users, comparing the feature template to a plurality of previous feature vectors to determine a match;
when the match is determined, sending a security breached signal to the REE; and
when the match is not determined:
replacing a selected one of the previous feature vectors with the feature vector; and
continuing the authentication operation;
wherein the REE is configured to deny authentication in response to receiving the security breached signal.
2 . The system of claim 1 , wherein:
the REE is configured to implement the feature extractor and to send the feature vector to the secure element in response to receiving the sensor output signal.
3 . The system of claim 1 , wherein:
the secure element is configured to receive the sensor output signal and to implement the feature extractor.
4 . The system of claim 1 , further including:
an interface circuit operatively coupled to the secure element and configured to condition the sensor output signal for the secure element, wherein conditioning the sensor output signal for the secure element includes:
receiving the sensor output signal;
transforming the sensor output signal to produce a transformed sensor output signal; and
providing the transformed sensor output signal to the secure element,
wherein the secure element is configured to receive the sensor output signal and to implement the feature extractor.
5 . The system of claim 1 , further including:
a memory operatively coupled to the secure element; and
wherein the secure element is configured to store the plurality of previous feature vectors in the memory.
6 . The system of claim 1 , wherein:
the secure element includes a memory; and
wherein the secure element is configured to store the plurality of previous feature vectors in the memory.
7 . The system of claim 1 , wherein:
the REE is configured to approve authentication in response to determining that the feature vector does not equal any of the previous feature vectors and in response to authenticating the sensor output signal.
8 . The system of claim 1 , further including:
a biometric sensor configured to produce the sensor output signal.
9 . A system comprising:
a sensor configured to produce a sensor output signal;
an interface circuit configured to transform the sensor output signal to produce a transformed sensor output signal;
a rich execution environment (REE) configured to use the sensor output signal to approve or to deny authentication;
a feature extractor configured to produce a feature vector from the sensor output signal or the transformed sensor output signal; and
a secure element operatively coupled to the REE and configured to perform an authentication operation and to detect a replay attack, wherein detecting the replay attack includes:
comparing the feature vector to a plurality of previous feature vectors to determine a match;
when the match is determined, sending a security breached signal to the REE; and
when the match is not determined:
replacing a selected one of the previous feature vectors with the feature vector; and
continuing the authentication operation; and
wherein the REE is configured to deny authentication in response to receiving the security breached signal.
10 . The system of claim 9 , wherein:
the secure element includes the feature extractor; and
the feature extractor is configured to produce the feature vector from the transformed sensor output signal.
11 . The system of claim 10 , wherein the interface circuit is operatively coupled to the sensor and to the secure element.
12 . The system of claim 11 , wherein:
the sensor is configured to add a challenge to the sensor output signal and to communicate the challenge to the secure element;
the REE is configured to produce a challenge indicator from the challenge;
the secure element is configured to use the challenge to confirm the challenge indicator; and
the secure element is configured to send the security breached signal to the REE in response to determining that the challenge does not match the challenge indicator.
13 . The system of claim 12 , further including:
a memory operatively coupled to the secure element; and
wherein the secure element is configured to store the plurality of previous feature vectors in the memory.
14 . The system of claim 10 , wherein the sensor includes the interface circuit.
15 . The system of claim 9 , wherein:
the REE includes the feature extractor; and
the feature extractor is configured to produce the feature vector from the sensor output signal and to provide the feature vector to the secure element.
16 . The system of claim 15 , wherein the sensor is a biometric sensor.
17 . The system of claim 16 , wherein the biometric sensor is a camera.
18 . A method for denying authentication in response to detecting a replay attack, the method comprising:
producing a feature vector from a sensor output signal;
comparing, by a secure element, the feature vector to a plurality of previous feature vectors in a memory to determine a match;
in response to determining the match, sending, by the secure element, a security breached signal to a REE;
when the match is not determined, storing, by the secure element, the feature vector to replace a selected one of the previous feature vectors; and
wherein the REE is configured to deny authentication in response to receiving the security breached signal.
19 . The method of claim 18 , further including:
producing, by a sensor, the sensor output signal; and
transforming, by an interface circuit, the sensor output signal to produce a transformed sensor output signal that is provided to the secure element,
wherein the secure element uses the transformed sensor output signal to produce the feature vector.
20 . The method of claim 18 , wherein:
the REE is configured to approve authentication in response to determining that the feature vector does not equal any of the plurality of previous feature vectors and in response to authenticating the sensor output signal.