Patent Application
20230259200
One or more aspects of embodiments according to the present disclosure relate to authentication, and more particularly to authentication based on a user's eye motion.
In various circumstances it may be desirable to secure access to a resource (e.g., to an asset) by requiring that a user be authenticated before the user is granted access. A method of authentication that requires the user to enter a password or personal identification number (PIN) may be vulnerable to a playback attack, in which an adversary observes successful access to the system by an authorized user, and the adversary then gains access by supplying the same password or PIN.
It is with respect to this general technical environment that aspects of the present disclosure are related.
These and other features and advantages of the present disclosure will be appreciated and understood with reference to the specification, claims, and appended drawings wherein:
The apparent distance of the object 105 from the user may be determined by an angular offset θ, the angular offset being defined as the angle between (i) a first line between the user's right eye and the object as displayed in the right display and (ii) a second line, between the user's left eye and the object as displayed in the left display. When a user looks at the object, both of the user's eyes are aimed at the object, and the angle between the pointing directions of the user's eyes, which may be referred to as the “vergence” of the user (or of the user's eyes), may be equal to the angular offset for the object. The vergence (or the angular offset θ), expressed in radians, may be approximately equal to the distance x between the user's pupils divided by the distance y to the object.
The display drive system may similarly display, to the user, other objects, e.g., of a plurality of simultaneously displayed objects. Each such object may be, for example, a simple shape, such as a sphere, a pyramid, or a cube, or it may be an alphabetical character or a numerical digit, or it may be a more complex object such as a machine or a plant or an animal. All characteristics of displayed objects, as described herein, are apparent characteristics, and, as such, the qualifier “apparent” may be omitted. For example, the apparent height of an object may be referred simply as the height of the object, and the apparent distance between the user and an object may be referred to simply as the distance between the user and the object.
The binocular display may be fixed, e.g., secured to a wall of a building, or it may be worn by the user (e.g., installed in glasses or goggles, or, as discussed in further detail below, in contact lenses).
In some embodiments, the display drive system may display the digits at different distances from the user. For example, the digit 2 may be displayed so as to appear nearer the user than the digits 1 and 3, as shown in
In some embodiments, the size of each digit (i.e., the absolute size that the user perceives each digit to have, taking into account its apparent distance from the user) may be adjusted in proportion to its distance from the user, so that each digit has substantially the same angular size when viewed by the user. For example, the display drive system may render (i) a first digit that in three-dimensional space has a height of 10 cm and is at a distance of 50 cm from the user, and a second digit that has a height of 20 cm and is at a distance of 1 meter from the user.
In some embodiments, other characteristic of the digits, other than distance from the user, may be randomly varied instead of, or in addition to, their distance from the user. For example, as illustrated in
In some embodiments, the objects are, or include, objects that are not digits, e.g., simple two-dimensional shapes like a circle or a square, or three-dimensional shapes like a cube. In such an embodiment the system may otherwise work in a manner analogous to that described above for a system using digits, with the user looking at a set of objects in predefined order (e.g., looking at a cube, a circle, and a square, in order), and with the distance of each object from the user being randomly selected (and mirrored in the user's vergence) to thwart playback attacks. As used herein, an object displayed on one occasion may be considered to be the same object as an object displayed on another occasion if the user would regard the two objects to be the same. For example, if the digit 2 is displayed in a first position on a first occasion and in a second position on a second occasion, it may be described as one object (the digit 2) having been displayed in two different locations.
Other aspects of a user's eye motions may be used to authenticate a user, and also to maintain authentication of a user (e.g., to maintain confidence, some time after an explicit authentication, that the current user is the same user who performed the explicit authentication). For example, different users may train their eyes on a target at different rates, and when a user sees a new object, the user's eyes may briefly converge on a point closer to the user than the object, before looking at the object. Further, when a user looks at an object, the user's eyes may not point precisely at the object, but each eye may instead point in a direction that is sufficiently close to the object that the image of the object nonetheless falls on the fovea (the brain may then correct for the pointing errors in estimating the distance to the object). These characteristics may vary from user to user, and also may be poorly emulated by a machine (e.g., a machine used for a playback attack), and, as such, may be used for authentication. When the display is a non-obscuring display (a display that does not block the user's view of the user's surroundings), such as glasses, or (as discussed below) contact lenses, that superimpose the displayed images onto the user's view of the user's surroundings, the objects used to verify “liveness” (the continuous interaction, with the display, of a human user) may be objects generated by the display or physical objects in the user's surroundings. If the user has amblyopia, then the system may control for this characteristic, and authenticate the user even though the vergence does not match the angular offset (but instead matches a different vergence, which the system may predict based on the angular offset and the (e.g., previously measured) characteristics of the user's amblyopia). Moreover, the presence of amblyopia may also be used as a factor in an authentication scheme.
In some embodiments, the binocular display includes two contact lenses, each with a respective display, which may be a projector for projecting images onto the retina. As used herein, a binocular display that is not a pair of contact lenses may be referred to as an “external” binocular display.
When the binocular display is a pair of contact lenses, each with a respective display, the display system may be configured to compensate for motion of the user's eyes. For example, if the user's right eye turns to the left, the projector may adjust the position of the image of a displayed object on the retina so that the direction to the object (e.g., in a frame of reference anchored to the user's surroundings) remains constant. In this manner, the images supplied to the user's eyes by a contact lens may, like images supplied by an external display (e.g., a wall-mounted display or a display installed in glasses or goggles), show each object in a direction that is independent of the motion of the user's eyes. The orientation of each eye may be sensed in all three rotational degrees of freedom (e.g., by three gyroscopes in the contact lens), and the correction for eye motion may be performed in all three degrees of freedom (including roll, a degree of freedom in which the user's eyes may move when looking at an object that is both above or below the horizontal, and close to the user (so that the vergence is significant)).
Each of the contact lenses may be connected, e.g., by a wireless connection, to a relay accessory, which may be a user-carried or user-worn accessory, such as a mobile phone. The relay accessory may supplement the processing capabilities of the contact lenses, which may be limited because of constraints on volume, in the contact lens, for processing circuits and for batteries to power them. The relay accessory may also provide access (e.g., via the Internet) to various external services, e.g., sources of information that may be displayed to the user. In some embodiments, the relay accessory requires an explicit authentication from the user when the user first begins wearing the contact lenses, and thereafter if the liveness signal is lost during an interval that is sufficiently long that during the interval the user could have removed the contact lenses and another user begun wearing them. The resource to which the authentication method restricts access may be the contact lens system itself, or another resource (e.g., access to a building).
The detailed description set forth above in connection with the appended drawings is intended as a description of exemplary embodiments of a system and method for authentication provided in accordance with the present disclosure and is not intended to represent the only forms in which the present disclosure may be constructed or utilized. The description sets forth the features of the present disclosure in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the scope of the disclosure. As denoted elsewhere herein, like element numbers are intended to indicate like elements or features.
As used herein, “a portion of” something means “at least some of” the thing, and as such may mean less than all of, or all of, the thing. As such, “a portion of” a thing includes the entire thing as a special case, i.e., the entire thing is an example of a portion of the thing. Similarly, a subset of a set may be the entire set or a proper subset of the set. As used herein, the word “or” is inclusive, so that, for example, “A or B” means any one of (i) A, (ii) B, and (iii) A and B.
As used herein, when a method (e.g., an adjustment) or a first quantity (e.g., a first variable) is referred to as being “based on” a second quantity (e.g., a second variable) it means that the second quantity is an input to the method or influences the first quantity, e.g., the second quantity may be an input (e.g., the only input, or one of several inputs) to a function that calculates the first quantity, or the first quantity may be equal to the second quantity, or the first quantity may be the same as (e.g., stored at the same location or locations in memory as) the second quantity. As used herein, when an action is taken “in response to” a first condition, the action may be taken solely in response to the first condition, or in response to the first condition and one or more other conditions. As used herein, comparing a first quantity and a second quantity includes comparing a function of the first quantity to a function of the second quantity.
Although exemplary embodiments of a system and method for authentication have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that a system and method for authentication constructed according to principles of this disclosure may be embodied other than as specifically described herein. The invention is also defined in the following claims, and equivalents thereof.
