CN111783919A

CN111783919A - Physically unclonable function for security in bank cards or identity cards

Info

Publication number: CN111783919A
Application number: CN201910272191.XA
Authority: CN
Inventors: 罗杰·史蒂文·坎农; 威廉·科比特; 加里·A·丹顿; 卡尔·E·苏里万; 詹姆斯·P·德拉蒙德; 凯利·安·基利恩
Original assignee: Lexmark International Inc
Current assignee: Lexmark International Inc
Priority date: 2019-04-04
Filing date: 2019-04-04
Publication date: 2020-10-16

Abstract

The present disclosure relates to, but is not limited to, physically unclonable functions for security in integrated circuit chip packages. In the described invention, the magnetic field characteristics using randomly placed magnetized particles are exploited by using the magnetic field fluctuations generated by the particles measured by the sensor. The magnetized particles generate a complex magnetic field near the surface of the integrated circuit chip on the bank card or identification card, which can be used as a "fingerprint". The positioning and orientation of magnetized particles is an uncontrolled process and therefore the interaction between the sensor and the particles is complex. The randomness of the magnitude and direction of the magnetic field near the surface of the material containing the magnetic particles may be used to obtain a unique identifier of an item, such as an integrated circuit chip carrying the PUF on a bank card or an identification card.

Description

Physically unclonable function for security in bank cards or identity cards

Background

1. Field of disclosure

The present disclosure relates generally to anti-counterfeiting systems, and more particularly to physically unclonable functions.

2. Description of the related Art

Due to reliability and security issues, counterfeit integrated circuit chips ("ICCs") are a major issue in the supply of electronic components. Such counterfeit ICC is affecting many industrial sectors including computers, printing, telecommunications, automotive electronics, medical, banking, energy/smart grid, aerospace and military systems. The latter effect can be very severe when critical systems begin to fail or perform malicious activities due to the use of counterfeit or low quality components, resulting in minor failures, major failures, or task failures (including health or safety issues).

For example, the National Defense Authorization Act (NDAA) of 2012 was primarily directed to a national defense contractor who did not check for counterfeit parts in their equipment. According to the article "NDAA May Put a failure in containment in princon For counter life Parts" on 2.14.2.2012 by forbes, contractors who do not eliminate Counterfeit electronic components in military equipment May assume civil and criminal responsibilities.

The tools and techniques used by counterfeiters have become extremely complex and capital intensive. This, in turn, requires a more sophisticated method to detect counterfeit electronic components entering the market. Hardware intrinsic security is a mechanism that provides security based on the intrinsic properties of an electronic device. Physical unclonable functions ("PUFs") belong to the field of intrinsic security of hardware.

In the printer industry, counterfeit printer supplies, including ICCs, are a problem for consumers. Counterfeit supplies may perform poorly and may damage the printer. Printer manufacturers use authentication systems to deter counterfeiters. PUFs are one type of authentication system that implements a physical one-way function. Ideally, PUFs cannot be fully duplicated and are therefore difficult to counterfeit. Including a PUF in an electronic device package (including an ICC) can deter counterfeiters.

SUMMARY

In the described invention, the magnetic field characteristics using randomly placed magnetized particles are exploited by using the magnetic field fluctuations generated by the particles measured by a sensor such as a hall effect sensor or an array of such sensors. The present invention consists of ICC's encapsulated in or overmolded with a substrate containing magnetic particles. Magnetized particles generate a complex magnetic field near the ICC surface, which can be used as a "fingerprint". The positioning and orientation of magnetized particles is an uncontrolled process and therefore the interaction between the sensor and the particles is complex. It is therefore difficult to replicate the device such that the same magnetic pattern and particle physical location pattern is produced. The randomness of the magnitude and direction of the magnetic field near the surface of the material containing the magnetic particles may be used to obtain a unique identifier of an item, such as an integrated circuit chip carrying the PUF. Furthermore, placing the device in the top layer of the integrated circuit chip protects the underlying circuitry from inspection by an attacker, e.g. for reverse engineering. When a counterfeiter attempts to remove all or part of the coating, the magnetic field profile must change, thereby destroying the original unique identifier.

The invention relates in one form thereof to an integrated circuit chip covered or encapsulated by a PUF containing randomly placed magnetic particles.

The invention relates, in another form thereof, to an integrated circuit chip for use in a printer or printer supply (e.g., toner cartridge), the integrated circuit chip being covered or encapsulated by a PUF containing randomly placed magnetic particles.

The invention relates in yet another form thereof to an EMV (european payments, mastercard, visa) transaction chip or embedded microchip on a bank card covered by a PUF containing randomly placed magnetic particles.

The invention relates in yet another form thereof to a device having an EMV transaction chip mounted on a substrate forming the body of a bank card, wherein a plurality of magnetized particles are dispersed in the substrate to form a PUF.

Drawings

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate several aspects of the present disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 is a view of an integrated chip.

Fig. 2 is a view of an integrated chip with magnetized particles molded in a housing.

FIG. 3 is a view of an integrated chip with an array of sensors formed over the chip and magnetized particles molded in the housing.

Fig. 4 is an orthogonal view of a substrate containing magnetic and non-magnetic particles.

Figure 5 is a side view of a PUF and a PUF reader.

Fig. 6 is a view of the front side of a bank card with an EMV transaction chip.

Figure 7 is a view of the back of a bank card with a magnetic stripe.

Figure 8 is a bank card chip reader device.

Figure 9 is an end view of a bank card chip reader device.

Fig. 10 is a flow chart of a method of manufacturing a security device.

FIG. 11 is a magnetic field profile along a defined path.

FIG. 12A, FIG. 12B and FIG. 12C are diagrams illustrating the decomposition into three coordinate components B_x、B_yAnd B_zA three-dimensional representation of the measured magnetic flux density over the area of (a).

Detailed Description

In the following description, reference is made to the accompanying drawings in which like numerals designate like elements. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the present disclosure. Examples merely typify possible variations. Portions and features of some embodiments may be included in, or substituted for, those of others. The following description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims and equivalents thereof.

Referring now to the drawings, and in particular to fig. 1, when fabricating an ICC 1001, the packaging is typically done by attaching to a metal leadframe 1008, the metal leadframe 1008 is connected to

bond pads

1002 and 1003 by

wire bonds

1004 and 1005, and then enclosed in an encapsulant 1006, which encapsulant 1006 is then cured. The encapsulated chip is then molded into a plastic housing 1007.

Referring now to fig. 2, in one embodiment of the invention, the molded plastic housing 1007 is replaced by a molded plastic housing or substrate 2007 in which is dispersed a plurality of magnetized particles 4014. The particles are randomly distributed, making it extremely difficult to reproduce the precise distribution and alignment of the particles. Preferably, the particles are magnetized prior to dispersion in the substrate to further increase the randomness of the resulting magnetic field distribution. Thus, the substrate 2007 and the particles 4014 form a physically unclonable function outside the molded plastic shell.

The magnetic field profile near the surface of the ICC can be measured by an external magnetoresistive sensor, a hall effect sensor (not shown), or an array of such sensors in close proximity to the top surface of the ICC. Since the sensing element is typically around 0.3-0.5 mm below the surface of the sensing device, the average particle size (average particle size) of the sensor using a hall effect sensor or a magnetoresistive sensor is preferably greater than 0.1 mm. Note that the diameter of the non-spherical particle is the diameter of the smallest sphere enclosing the particle. Other sensor options include magneto-optical sensor technology that can work with smaller magnetic particle sizes, but is more costly to implement and is susceptible to contamination problems.

The magnetic field distribution measurement may be made within a defined area or along a defined path: straight, circular or any arbitrarily chosen and defined path and recorded at the ICC manufacturer. FIG. 11 shows the magnetic field distribution along a defined pathIn which the magnetic flux density has been decomposed into three coordinate components B_x、B_yAnd B_z. Fig. 12A-12C show magnetic field distributions measured over a rectangular area as exhibited by a defined area of the overlaid ICC. The distribution is a three-dimensional representation of the magnetic flux density measured over the entire area. The magnetic flux density vector has been decomposed into three coordinate components B shown in fig. 12A, 12B, and 12C, respectively_x、B_yAnd B_z. The magnetic field profile data will be signed by the private key and written to the non-volatile memory ("NVM") of the ICC during programming. After the ICC is mounted on the circuit card, the magnetic "fingerprint" is again read by the external magnetoresistive sensor and the magnetic profile is compared with the values stored on the chip to authenticate the ICC. This system would make it difficult for counterfeit ICCs to enter high-value applications. The system is rather cheap to implement and can almost instantaneously authenticate PUF overmolded ICCs.

Referring now to fig. 3, in a second embodiment of the invention, the use of magnetized particles 4014 produces a unique magnetic fingerprint that can be applied to the fabrication of ICCs by overmolding the encapsulated chip 1001 with a substrate containing magnetized particles 2007. The term "overmolding" is used broadly herein to refer to any addition of a partial surface layer over an ICC to completely encase the ICC. One or more sensors, such as hall effect sensors 3001, are formed over the chip body and enclosed within a housing 2007. In this embodiment, the sensor 3001 may record a series of analog magnetic strength readings at different locations along the substrate in one, two, or three coordinate directions. Such "internal" hall effect sensors can measure average particle sizes of less than 0.1 mm. Since these measurements are analog voltages, with sufficient number of measurements and sufficient analog-to-digital resolution, unique values can be derived from these measurements. These values may be used for private keys, seeds (seed), etc., which are not stored in the memory of the device. Instead, they are read and acquired by the device "in flight" (i.e. during operation), thus invalidating any probing attack on the chip itself by a counterfeiter. If a counterfeiter attempts to extract the private key from the ICC, it is very likely that the overmolded magnetic layer will be disturbed and the private key will be lost.

These embodiments may be implemented, for example, on an integrated circuit chip on a printer or printer supply (e.g., toner cartridge) that is used to authenticate the toner cartridge for any purpose, as well as to perform other functions, such as toner level monitoring, sheet counting, etc.

A third embodiment of the present invention is to apply PUF authentication techniques to bank cards and identity cards with EMV transaction chips. For example, the bank card 6001 is constantly under attack by counterfeiters. To this end, the EMV transaction chip 6002 mounted on the substrate 6003 replaces the magnetic strip 7001, which is easily counterfeited, as shown on the back of the bank card 6001 in fig. 7. To avoid fraud, EMV transaction chips may be used with personal identification numbers ("PINs"), but for the convenience of customers, many cards lack such additional protection to reduce data requirements in transactions and to avoid software upgrades for PIN operations.

Bank cards with EMV transaction chips are mostly used in a contact-based form: the card is inserted into a card reader, which creates a circuit that allows handshaking between the card and the payment terminal. A unique transaction involving encrypted data embedded in the chip is generated.

For cards that require a PIN, the transaction cannot be completed without a code (code), which is not transmitted remotely as in debit cards and ATM transactions. Some cards are equipped with Near Field Communication (NFC) radios for contactless EMV transactions and will be used with point-of-sale systems.

A unique magnetic PUF signature that simulates a magnetic field strength reading can replace the PIN requirement to authenticate a bank card. The PUF signature will be the second authentication factor for the bank card.

The substrate of the bank card may be manufactured wherein dispersed in the substrate is a plurality of magnetic particles. The particles are randomly distributed, making it extremely difficult to reproduce the precise distribution and alignment of the particles. The substrate and the particles of the bank card thus form a physically unclonable function. The magnetic field distribution may be measured by an external sensor, such as a hall effect sensor (not shown) in close proximity to the surface of the bank card. Other sensor options include magneto-optical sensor technology. The magnetic field distribution measurement may be made within a defined area or along a defined path: straight, circular or any arbitrarily chosen and defined path and recorded during the bank card manufacturing process. The magnetic field distribution data will be written to the non-volatile memory of the EVM transaction chip.

When card reader 8001 is inserted, the card reader may sweep a sensor arm (sensor arm) across a portion of the rowcard and one or more sensors (e.g., hall effect sensors) located on the sensor arm will measure the magnetic field in a defined area or along a defined path. A simple mechanical arrangement with a drive cam will determine the path that the sensor arm scans. Alternatively, as shown in fig. 9, when a bank card is inserted into the card reader slot 8002, the sensor or sensor array may be in a fixed position where the bank card slides past the

sensors

8003, 8004, 8005, and 8006. Data corresponding to the magnetic strength readings along the sensing path is stored in the non-volatile memory of the EMV transaction chip and used to verify the magnetic "fingerprint" detected by the card reader at the time of the transaction. The invention does not require the user to remember the PIN and the card reader can perform authentication locally. Alternatively, the card reader may be configured to transmit a magnetic "fingerprint" to a bank card company server or cloud location for remote authentication when a high value transaction occurs. Data stored at the cloud location is stored in an accessible network (e.g., the internet) on physical storage devices (e.g., computer servers and storage networks).

As an additional layer of security, the EMV transaction chip on the card may contain information that will direct the card reader to read a magnetic "fingerprint" in a particular location on the bank card. This location may be different for different cards and add yet another layer of complexity to the task of counterfeiting bank cards. The varying positions of the magnetic "fingerprint" may also be configured to act as a rotating encryption key. The rotation key may change daily, weekly, or monthly. Rotating the key can be as simple as two keys, of which data is read from the "fingerprint" in a forward or backward motion, which is the least disruptive for current reader configurations. Known algorithms can be used to determine when the "fingerprint" is rotating.

In another embodiment, the bank card substrate on which the EMV transaction chip is mounted may be the location of a magnetic "fingerprint" such that removal or alteration of the EMV transaction chip will distort the substrate and thereby alter the magnetic "fingerprint" such that authentication is inoperable. In another embodiment, the bank card may be implemented to cause the fingerprint to tear if the chip is removed.

The card reader may initiate bank card authentication by sending a request for data to an EMV transaction chip on the bank card. The bank card EMV transaction chip may initiate a challenge to the card reader and wait for an appropriate response (authenticating the card reader) before the bank card security chip sends magnetic "fingerprint" authentication data to the card reader. Such challenge and response protocols make it more difficult for counterfeiters to obtain data from bank cards. In addition to using a magnetic "fingerprint" or signature of a bank card, capacitive sensing techniques may be used to detect the presence of randomly distributed magnetized particles in the bank card, which may provide yet another authentication step for verifying the bank card.

The presence of magnetized particles can be optically detected by a digital camera chip or by an optical sensor if at least one face of the bank card is opaque. Similar to capacitive sensing, this may provide an additional authentication step for the bank card.

The technique may also authenticate access tokens (accessbadges) for security facilities, or access tokens for other applications (e.g., passports, identification cards, driver's licenses, etc.) in the same manner as described above. PUF technology may stand alone as a security device or be combined with an integrated circuit chip on an identification card or other security device with non-volatile memory.

Fig. 4 shows a region of a substrate 4010. Dispersed in the substrate are a plurality of magnetized particles 4014. The particles are randomly distributed, making it extremely difficult to reproduce the precise distribution and alignment of the particles. Thus, the substrate 4010 and the particles 4014 form a PUF.

Fig. 5 shows a side view of a substrate 4010 comprising magnetized particles 4014.

The field data may be measured while moving the PUF relative to the fixed

magnetic field sensors

5001, 5002, 5003 or by moving the

magnetic field sensors

5001, 5002, 5003 in close proximity to the fixed PUF, etc. The sensors are shown in different orientations, but such different orientations are not required. Multiple sensors may be used to reduce the movement and time required to measure the magnetic field over a desired area.

Fig. 10 shows an example of a method of manufacturing a security device, such as an integrated circuit chip with a PUF overlay or a bank card with an EMV transaction chip and a PUF substrate.

The magnetizable particles may be of any shape and may comprise neodymium and iron, as well as boron. Alternatively, the magnetisable particles may comprise samarium and cobalt. Preferably, the magnetized particles generate a magnetic field strong enough to be detected with a low cost detector.

A suitable base material is used which allows the base material and the formed aggregated particles (pellet) of particles to be magnetized. The magnetisable particles are magnetised by e.g. subjecting the particles to a strong magnetic field. After magnetization, the magnetic particles do not aggregate together because the particulate support material is a solid. During the molding process, the pellets are heated and melted prior to molding.

The substrate carrier is then cured in the ICC in the body of the bank card or in a portion of the bank card located below the location of the EVM transaction chip, overlaying, encasing, the ICC. In alternative embodiments, the carrier may be, for example, a liquid that is caused to become solid by the addition of chemicals, exposure to ultraviolet light, increasing its temperature, and the like. Causing the carrier to become solid, locking the distribution and orientation of the particles. In this case, a high viscosity liquid is preferred so that the particles can be magnetized shortly before the material is moulded. When the material is in a liquid state, the high viscosity hinders the movement of the magnetic particles towards each other and minimizes the aggregation of the magnetized particles. Aggregation can cause the overmolding process to fail.

Magnetizing particles in granular form produces a more random magnetic field pattern and is therefore more difficult to clone. Furthermore, the application of a magnetization field with a patterned or randomized orientation can be applied to a formed substrate with random particle positions in order to induce a greater diversity of magnetic field orientations.

What has been described above illustrates aspects and examples of the present disclosure. The foregoing description is not intended to be exhaustive. Rather, the foregoing description was chosen to illustrate the principles of the present disclosure and its practical application to enable one of ordinary skill in the art to utilize the present disclosure, including various modifications thereof. All such modifications and variations are considered to be within the scope of the present disclosure as determined by the appended claims. Relatively obvious modifications include combining one or more features of various embodiments with features of other embodiments.

Claims

1. An apparatus, comprising:

a base forming the body of a bank card;

an EVM transaction chip on the bank card;

a plurality of magnetized particles randomly dispersed in the substrate; and

a non-volatile memory on the EVM transaction chip, wherein the non-volatile memory contains magnetic field distribution data measured from the magnetized particles.

2. The apparatus of claim 1, wherein the magnetized particles comprise neodymium and iron and boron.

3. The apparatus of claim 1, wherein the magnetized particles comprise samarium and cobalt.

4. The apparatus of claim 1, wherein the magnetized particles have an average particle size of greater than 0.1 mm.

5. The apparatus of claim 1, wherein the magnetized particles have an average particle size of less than 0.1 mm.

6. The apparatus of claim 1, wherein the substrate containing the magnetized particles directly contacts the EVM transaction chip.

7. A system, comprising:

a base forming the body of a bank card;

an EVM transaction chip on the bank card;

a plurality of magnetized particles randomly dispersed in the substrate;

a non-volatile memory on the EVM transaction chip containing magnetic field distribution data measured from the magnetized particles;

a card reader; and

one or more sensors in the card reader, wherein the sensors measure a magnetic field in a defined area of the bank card or along a defined path of the bank card when the bank card is inserted into the card reader.

8. The system of claim 7, wherein the magnetized particles comprise neodymium and iron and boron.

9. The system of claim 7, wherein the magnetized particles comprise samarium and cobalt.

10. The system of claim 7, wherein the magnetized particles have an average particle size of greater than 0.1 mm.

11. The system of claim 7, wherein the magnetized particles have an average particle size of less than 0.1 mm.

12. A system, comprising:

a base forming the body of a bank card;

an EVM transaction chip on the bank card;

a plurality of magnetized particles randomly dispersed in the substrate;

a cloud location containing magnetic field distribution data measured from the magnetized particles;

a card reader; and

13. The system of claim 12, wherein the magnetized particles comprise neodymium and iron and boron.

14. The system of claim 12, wherein the magnetized particles comprise samarium and cobalt.

15. The system of claim 12, wherein the magnetized particles have an average particle size of greater than 0.1 mm.

16. The system of claim 12, wherein the magnetized particles have an average particle size of less than 0.1 mm.

17. An apparatus, comprising:

a substrate forming a body of an identity card;

an integrated circuit chip on the identification card;

a plurality of magnetized particles randomly dispersed in the substrate; and

a non-volatile memory on the integrated circuit chip, wherein the non-volatile memory contains magnetic field distribution data measured from the magnetized particles.