阅读说明：本技术 用智能手机扫描物理不可克隆功能的物理签名数据的设备和方法 (Device and method for scanning physical signature data of physical unclonable function by using smart phone ) 是由 斯科特·理查德·卡斯尔 罗伯特·亨利·麦森肯斯 布兰特·丹尼斯·尼斯托姆 托马斯·尤金·潘伯恩 于 2020-03-06 设计创作，主要内容包括：通过将预磁化或后磁化颗粒模制到树脂内来创建独特的物理不可克隆功能对象。颗粒基于随机颗粒大小、位置、极性旋转、磁化水平、颗粒密度等形成独特的物理“指纹”。本发明解决的是用于准确地测量PUT的特别地包括在PUT上的足够分立的点处的磁场的X、Y和Z分量的物理指纹以允许对身份的有把握地识别的设备。描述了固定有PUT标签的结构元件,该结构元件可以被用于通过沿着电话的侧面扫滑结构元件并用导向器控制PUT标签的位置来用智能手机磁力计扫描PUT标签。(Unique physically unclonable functional objects are created by molding pre-magnetized or post-magnetized particles into a resin. The particles form a unique physical "fingerprint" based on random particle size, location, polarity rotation, magnetization level, particle density, and the like. The present invention addresses a device for accurately measuring the physical fingerprint of the PUT, specifically comprising X, Y and the Z component of the magnetic field at sufficiently discrete points on the PUT to allow for the confident identification of an identity. Structural elements are described to which PUT tags are affixed that can be used to scan the PUT tags with a smartphone magnetometer by swiping the structural element along the side of the phone and controlling the position of the PUT tags with a guide.)

1. An apparatus for scanning magnetic signature data of a Physical Unclonable Function (PUF) using a smartphone, comprising:

a support structure to which a PUF tag is fixedly secured, the support structure being disposed on an edge of the smartphone;

a positioning structure that allows a user to hold the support structure with the PUF tag in place while providing direct contact between the user's finger or thumb and a smartphone touch screen to give positional input data.

2. The device of claim 1, wherein the support structure has springs or similar flexure support elements that allow smartphones of different thicknesses to be held as the support structure with the PUF tag slides along the edge of the smartphone.

3. The device of claim 1, wherein a capacitive rubber element is placed on an inner surface of the support structure such that when the support structure is in place on an edge of the smartphone, the capacitive rubber element is in contact with the smartphone touchscreen.

4. The device of claim 1, wherein the support structure has springs or similar flexure support elements that allow smartphones of various thicknesses to be held as the support structure with the PUF tag slides along the edge of the smartphone, and capacitive rubber elements are placed on an inner surface of the support structure such that they make contact with the smartphone touchscreen when the support structure is in place on the edge of the smartphone.

5. The apparatus of claim 1, wherein the support structure has a curved portion to accommodate a user's thumb or finger.

6. A method for capturing a magnetic signature of a physical unclonable function ("PUF") affixed to a support structure, comprising:

manufacturing the label with magnetic particles embedded in a PUF label;

securing the PUF tag to a support structure;

magnetically scanning the PUF tag to register magnetic signature data;

linking the PUF tag to a product;

scanning the PUF tag by aligning features on an edge of a smartphone and swiping the PUF tag over a magnetometer of the smartphone to measure the magnetic signature data of the PUF tag; and

the collected magnetic signature data is compared to magnetic signature data stored in a secure cloud environment for authentication.

7. The method of claim 6, wherein a finger of a user is in contact with a touchscreen of the smartphone during a scanning process to generate location data.

8. The method of claim 6, wherein the magnetic signature data is uploaded to a secure cloud environment.

9. The method of claim 6, wherein the magnetic signature data is uploaded to a secure server.

10. The method of claim 6, wherein the structural element is flipped and a second surface is scanned.

11. The method of claim 6, wherein an application on the smartphone provides an indication to a user regarding: direction of swipe, speed of swipe the label, alert user if swipe is performed incorrectly, prompt user to swipe again if needed, and whether to flip the label and swipe the second surface.

Background

The present disclosure generally relates to an apparatus for capturing a physically measurable feature signature along a line on the surface of a physically unclonable functional object created by molding specialized particles into a resin or matrix.

SUMMARY

Unique Physically Unclonable (PUF) functional objects may be created by molding or squeezing specialized particles over a surface to create measurable physical features. PUFs can be pre-magnetized or post-magnetized particles into a resin or matrix. Pre-magnetized particles form a unique measurable magnetic "fingerprint" based on the random size, location, polarity rotation, magnetization level, particle density, etc. of the particles. PUF objects may also differ in other physical characteristics by having a mixture of magnetic, conductive (magnetic or non-magnetic), optically reflective or shaped, varying density or mechanical properties, resulting in random reflection, diffusion or absorption of particles of acoustic energy in a matrix or binder. The present invention contemplates sensing any feature, in any single or combination, along any line on a surface.

Described below are devices for accurately measuring the magnetic fingerprint of a PUF, which includes X, Y and Z components of the magnetic field at sufficiently discrete points on the PUF, to allow for the secure identification of an identity. The sensing device may also measure any combination of additional sensing technologies, including capacitive, optical (IR, visible and hyperspectral) or acoustic (sonic and ultrasonic). Each sensor may be discrete, combined adjacent to each other, or integrated into one sensing module. Although the present invention discusses a magnetic PUF and a magnetic sensor or reader, it should be understood that the sensing technology may be available in a wand or a phone.

A handheld wand for measuring PUF features along an arbitrary path is described. Due to the low cost of magnetometers, the preferred measurement sensor is a magnetometer. Furthermore, a structural element is described to which the PUF tag is fixed, which can be used to scan the PUF tag with a smartphone magnetometer by sweeping the structural element along the side of the phone and controlling the position of the PUF tag with a director. The structural element may be shaped to encourage the user to place a finger on the touch screen while holding the PUF tag in place on the edge of the smartphone. Touch screen contact by a user while swiping a structural element may generate position data.

Brief Description of Drawings

The above-mentioned and other features and advantages of the disclosed embodiments, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of the disclosed embodiments taken in conjunction with the accompanying drawings.

Figure 1 is a logic flow diagram for capturing a signature of a feature along an arbitrary path of a PUF using a scan bar.

FIG. 2 is a perspective view of a scan bar.

Fig. 3 is an arbitrary path for scanning a characteristic fingerprint of a PUF.

Figure 4 is a logic flow diagram for capturing a signature of a feature of a PUF tag using a smartphone or other device.

Figure 5 is a support structure for a PUF tag.

Figure 5A is an isometric view of a support structure for a PUF tag.

Figure 5B is a top view of a support structure for a PUF tag.

Figure 5C is an end view of a support structure for a PUF tag.

Figure 6 is a perspective view of a support structure for a PUF tag located on a smartphone or other device.

Figure 7 is a view of a measurement of a characteristic fingerprint of a PUF tag on a smartphone application.

Fig. 8 shows a slight difference in magnetometer positions for two smartphone models.

Figure 9 shows a top view of a support structure for a PUF tag located on a smartphone or other device, where contact of an operator's thumb with the smartphone touch screen provides a position measurement as the support structure slides to read a magnetic fingerprint of the PUF.

Figure 10 shows a top view of a support structure for a PUF tag located on a smartphone or other device, where contact of an operator's thumb with the smartphone provides a position measurement as the support structure slides to read a magnetic fingerprint of the PUF, and the support structure can be flipped a second time to read the magnetic fingerprint.

Detailed Description

It is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. As used herein, the terms "having," "including," and the like are open-ended terms that indicate the presence of stated elements or features, but do not exclude additional elements or features. The articles "a," "an," and "the" are intended to include the plural as well as the singular, unless the context clearly indicates otherwise. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Terms such as "about" and the like have contextual meanings for describing various features of an object, and such terms have their ordinary and customary meanings to those of ordinary skill in the relevant art. Terms such as "about," and the like, in a first context mean "approximately" to the extent as understood by one of ordinary skill in the relevant art; and in a second context for describing various features of the object, and in such second context means "within a small percentage of …" as understood by one of ordinary skill in the relevant art.

Unless limited otherwise, the terms "connected," "coupled," and "mounted," and variations thereof herein are used broadly and encompass direct connections, couplings, and mountings, as well as indirect connections, couplings, and mountings. Furthermore, the terms "connected" and "coupled" and variations thereof are not restricted to physical or mechanical connections or couplings. For ease of description, spatially relative terms (e.g., "top," "bottom," "front," "back," and "side," "below …," "below …," "lower," "above …," "upper," etc.) are used to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the device in addition to different orientations than those depicted in the figures. Furthermore, terms such as "first," "second," and the like, are also used to describe various elements, regions, sections, etc., and are also not intended to be limiting. Like terms refer to like elements throughout the description.

Unique magnetic objects are created by molding pre-magnetized particles into a resin (nylon, etc.). Pre-magnetized particles form a unique magnetic "fingerprint" based on the random size, location, polarity rotation, magnetization level, particle density, etc. of the particles. PUF objects may also differ in other physical characteristics by having a mixture of magnetic, conductive (magnetic or non-magnetic), optically reflective or shaped, varying density or mechanical properties, resulting in random reflection, diffusion or absorption of particles of acoustic energy in a matrix or binder. The present invention contemplates sensing any feature in any combination along a path. All these PUF features result in a physical fingerprint of an object that varies continuously in magnitude, direction or depth over an observable surface. These changes are decomposed into its direction or scaler components and stored for later verification.

However, there is a need for a hardware reader that can accurately measure the physical characteristics of a fingerprint of a tag. The reader preferably measures the X, Y and Z component magnetic fields at sufficiently distinct points on the PUF to allow a secure identification of the unique identity. Any one of the measured magnetic field components will satisfy the minimum system required. The reader hardware may incorporate any combination of sensing units or individual sensing units, including magnetic as well as optical (IR, visual or hyperspectral, focused or laser), capacitive or acoustic (sonic or ultrasonic) as described herein.

Described below are means for capturing magnetic and other signature features along an arbitrary path of a PUF. Referring now to the drawings and in particular to FIG. 1, a logic flow diagram of an exemplary embodiment is shown.

At 101, a PUF tag is manufactured and then, at 102, scanned at high resolution to find physical features of interest of the PUF tag to enroll PUF tag fingerprint information in a database. Scanning may include magnetic, optical (IR, visual or hyperspectral, focused or laser), capacitive or acoustic (sonic or ultrasonic) information over a surface. To this end, at 103, the information is uploaded to a secure cloud environment for subsequent access. However, the database is not limited to a cloud environment in 103, and servers or other local or remote resources may also be used. The registered data may be encrypted or directly stored in the remote cloud environment or locally, depending on the required security level. The visual store may include a barcode, a Quick Response (QR) code, or a field pattern image associated with the object. The visual pattern or picture may be printed or displayed on the object or represent any location that is easily accessible. The local storage may also include electronic devices using RFID (UHF, HF or LF) or directly connected wired devices, such as USB or credit card integrated circuits or bluetooth devices.

At 104, the user attaches the PUF tag to the item and scans the PUF tag to logically link a characteristic fingerprint of the PUF tag to the product. Attachment methods may include, for example, using adhesives, injection molding, or injection molding into existing parts. At 105, a downstream user in the business chain may identify and authenticate a given product using a reader device deployed in the supply chain.

At 106, see fig. 2, a reader 201 comprising one or more magnetic, optical (IR, visual or hyperspectral, focused or laser), capacitive or acoustic (sonic or ultrasonic) sensors 211 on the tip of a wand-type handheld device is used to scan or read the characteristic fingerprint of the PUF tag on a product. Placed near the feature sensor 211 on the tip of the wand is a position tracking device 221, which may be an optical sensor similar to those found in computer laser mice or Inertial Measurement Units (IMUs). The optical position tracking device 221 acquires high frequency image captures of the surface and calculates X, Y and θ (rotation) changes between each captured image in order to determine position movement. Other positioning locations may be substituted including, for example, a touch pad, a positioning arm (coordinate measuring machine ("CMM")), or time-of-flight acoustic or radio frequency technology. The device can communicate the reader characters and position data to a mobile or remote device for processing, or can perform calculations on an internal microprocessor (not shown) and provide feedback to the user through, for example, a user interface ("UI"), light emitting diodes ("LEDs"), or vibratory/tactile feedback.

At 107, as further shown in fig. 3, the user scans the label by bringing the wand into contact or near contact with the PUF label and sweeping along an arbitrary path 304. In fig. 3, the PUF tag 302 may be part of a larger element 301 or attached to a larger element 301. An arbitrary path 304 may begin at an arbitrary starting point 304 and end at an arbitrary ending point 305. A reference datum 303 may also be included. Due to the arbitrary nature of the potential swipe path, the cloned tag will need to successfully reproduce all the features of the entire tag surface, not just the known path. Thus, any scan path complicates the work of cloning PUF tags. Most sensing technologies require close proximity between the sensor and the PUF tag. An additional feature is to have a sensing device on the system that allows rotation and alignment to the PUF surface. A spring or universal alignment swivel (not shown) will assist in the ergonomics of alignment to the surface.

However, the additional level of security provided by an arbitrary scan path comes at a cost, as "identifying" the characteristic path of the data against a known enrolled fingerprint can become a more difficult or time-consuming processing task.

To minimize the more difficult task of identifying arbitrary paths, a sensible reference 303 may be inserted within the tag. In its simplest form, these may be voids or pores where no particles are present in a particular region of the label. The user will be directed to continue to sweep through the various paths until a certain number of benchmarks are encountered. Such a forced swipe across the fiducial enables the tag identification processing algorithm to quickly set the key data points and filter potential tags with the fiducial in the correct location.

At 108, during the swipe, the wand 201 captures position data and feature data at discrete locations along the arbitrary path 306.

At 109, the user may be notified (via, for example, a UI, LED, or vibration/tactile feedback) that the scan is complete in the event that the user quickly encounters various highly identifiable feature data and/or feature references. If the user does not encounter a highly discernable feature, the user may be instructed to continue the swipe until sufficient data is found or a positive feature fingerprint match is detected. The random nature of the variable amount of feature data captured depends on the arbitrary path, which creates additional security and increases the cloning difficulty 110.

At 111, the feature components are reprocessed to remove deviations from the rotation of the rod. The feature sensor and the optical position sensor track slightly different paths depending on the relative positions of the sensors. Since the objective is to match or identify the characteristic fingerprint, the expected position and rotation of the sensor based on the optical sensor data when the characteristic data is captured can be evaluated.

Rotation of the feature sensor at any given point introduces a secondary data processing step. The actual feature fingerprint data may be decomposed into three-dimensional vector components (BX, BY, and BZ) or sealer data. If the feature sensor is held exactly above the tag's particular X, Y coordinate and then rotated about the theoretical Z axis, the sensor values of BX, BY, and BZ will change for magnetism, but not for sealer data. This change is predicted mathematically as long as the angle of rotation measured by the optical sensor is known. Thus, for each magnetic data capture sequence, the calculated X, Y position of the magnetic sensor is recorded, and the calculated BX, BY, and BZ elements based on the known rotating magnetic field of the magnetic sensor are also recorded.

At 112, the characteristic fingerprint is compared to the original enrollment data to confirm authenticity.

In a second embodiment, a magnetic PUF tag is scanned for position control using a magnetometer and a screen of a smartphone. As described above, unique objects are created by molding pre-magnetized particles into a resin (nylon, etc.). Pre-magnetized particles form a unique magnetic "fingerprint" based on the random size, location, polarity rotation, magnetization level, particle density, etc. of the particles. Described herein is an element that enables commonly available mobile devices (e.g., smartphones) to function as handheld readers of PUF tags. These elements include: a smartphone specific user instruction for a magnetometer scan path; a user interface element; mechanical position control of tags in relation to a magnetic sensor of a smartphone; single or multiple capacitive touch points; device-related data amplification or filtering that compensates for the bias of the mobile device.

Referring now to the drawings and in particular to FIG. 4, a logic flow diagram of an exemplary embodiment is shown. At 401, see FIG. 5, a physically unclonable function tag 550 is fabricated and may be mounted on a structural element 500. At 402, the PUF tag 550 is magnetically scanned at high resolution to enroll magnetic fingerprint information in a database. To this end, at 403, the information is uploaded to a secure cloud environment for later access. However, the database is not limited to a cloud environment, and a server or other resources may also be used.

At 404, the user attaches the structural element 500 with the PUF tag 550 to the item and scans the PUF tag 550 to logically link the magnetic fingerprint of the PUF tag 550 to the product. At 405, a downstream user in the business chain may use a magnetic reader to identify and authenticate a given product. A user may utilize a programmed scanning device or install a mobile smartphone application ("app") to use smartphone 600 (see fig. 6) as a magnetic reader.

At 406, the operating system of the scanning device or an application on the smartphone provides an indication to the user about the magnetometer scan path. Different manufacturers of different smartphone models place the magnetometer at different locations. However, due to the main use of compasses (compass) within smartphone mobile devices, magnetometers are typically placed on the outer edges of the device. E.g. twoThe model shows a slight difference in the position of the magnetometers (see fig. 8, e.g. iPhoneAnd iPhone). Furthermore, a further difference is the thickness of the handset, and thus there is a difference in the "depth" between the measurement element in the magnetometer and the back of the handset. This difference in depth will have an effect on the amplitude of the captured magnetic signature. For example, a smartphone with a slightly thicker piece of glass on the back of the smartphone will create a larger gap between the PUF tag 550 and the sensing element. This will produce a lower amplitude version of the magnetic signature. The approximate profile will remain the same in most cases, but the peak amplitude is smaller. Based on knowing what smartphone model to perform the scan, a device dependent amplification algorithm can be used to compensate for this amplitude effect.

When the smartphone application is started, it is typically able to detect the handset model from which the application can reference the database to determine where the magnetometer is located on that given model of device. The application may then give an indication of how the user should scan their PUF label 550 on the device. For example, on a smartphone application, the user may be guided where on the edge of the phone the structural element 500 with the PUF tag 550 is located; see fig. 9, in what direction 903 the PUF tag 550 is swiped relative to the smartphone 600; at what speed the label is swiped; if the swipe 903 of the PUF tag 500 is performed too fast or too slow, the user is alerted and prompted to swipe again if necessary, and whether to flip the tag 1004 and swipe the second surface 1005 (see fig. 10). When the PUF tag is flipped and scanned so that the magnetic surface of the PUF tag 500 is in contact with the screen-side surface of the smartphone 600, the magnetic signature is uniquely different, yet is still reproducibly consistent. Performing a secondary scan may yield another level of security and authentication for use cases requiring such a situation.

At 408, the user aligns the structural element 500 with the PUF tag 550 on the edge of the smartphone 600. See fig. 5. The support element 500 has a base element 503 that generally rests on the bottom of the smartphone 600. The top of support element 500 has tines (wings) 501, 502 that can rest on the touch screen 602 of smartphone 600. The gap between tines 501, 502 allows the user's thumb to contact touch screen 602. The gaps between the tines may have a curved portion to improve the grip of the user. The blocking element 505 abuts an edge of the smartphone 600 to position the PUF tag 550 relative to, for example, the magnetometers 802, 811. Note that magnetometers 802 and 811 are not exactly on the same location. Springs or similar flexure support structures (not shown) may be used to allow smartphones of various thicknesses to be held snugly as the PUF tag 550 is swept along the edge of the smartphone. One or more reference planes may be defined such that the PUF tag 550 is swiped over the smartphone magnetometer with positional consistency. In some implementations, the reference planes can be spaced apart such that the central gap remains open and any buttons on the sides of the phone can be swept across without affecting the path of the structural element 500 with the PUF tag 550.

By positioning the PUF label 550 against the surface 504 of the structural element 500, the PUF label 550 is positioned on the label of the structural element 500. Since the blocking element 505 abuts the edge of the smartphone 600, only a portion of the PUF tag 550 is read by the smartphone magnetometer. A wide enough portion of the PUF tag 550 is placed within the tag structure to allow for a margin of swipe and also to compensate for potential distance variations of the placement of the magnetometer along the edge of the smartphone. This is typically on the order of 5-10mm, but may deviate to 0-20 mm. As long as the PUF label 550 is permanently fixed prior to enrollment 402, precise positioning of the PUF label 550 on the structural element 500 is not required.

At 409, the tab structure with the gap between tines 501, 502 guides the user's finger or thumb into contact with smartphone screen 602. Alternatively, a capacitive element (e.g., a stylus) may be used, or may be incorporated into the structural element 500. In order to perform positionally accurate magnetic data capture at high frequency when the tag is swiped, the "location" position of the PUF tag 550 at each magnetic capture point must be recorded. Here, the touch screen surface 602 is used as an input sensor. The structural element 500 is shaped to encourage a user's finger to be placed on the touch screen 602 while holding the PUF tag 550 in place on the edge of the smartphone 600. The user interface may prompt the user to hold the PUF label 550 properly.

If some form of capacitive rubber material (such as that typically used in device styluses) can be permanently attached to the interior of the structural element 500 at a location similar to the area that would be the finger swipe area (such as on the inner ends of tines 501, 502). In this case, the structural element 500 will pass along the surface of the touchscreen 602 and provide a positional input that may be associated with a magnetic reading during the swipe of the PUF tag 550. In yet another embodiment, the capacitive touch elements may have individual features. With the addition of ultrasonic fingerprinting technology under modern touch screens on new generations of smartphone devices, the ability to use ultrasonic sensors to identify the structure of capacitive elements in contact with a surface becomes possible.

In the case where two capacitive rubber elements (not shown) are placed on the inner surface of the structural element 500 and then positioned on the touch screen for scanning, the smartphone application may calculate the skew factor without the user sweeping the structural element 500 along the edge of the smartphone 600 while holding the stop 504 of the structural element 500 against the edge of the smartphone 600. This skew factor will be used during the magnetic signature matching algorithm.

At 410, magnetometer field data BX, BY, and BZ and touch screen position data (p) are captured simultaneously as the user swipes the PUF tag 550, see fig. 7. The smartphone application may generate an X-Y plot in which the position is shown on the X-axis and the corresponding magnetometer field data is shown on the Y-axis.

The foregoing description of the embodiments has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the disclosure to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the claims appended hereto.