Abstract:
The invention disclosed herein is an in-circuit security system for electronic devices. The in-circuit security system incorporates identity credential verification, secure data and instruction storage, and secure data transmission capabilities. It comprises a single semiconductor chip, and is secured using industry-established mechanisms for preventing information tampering or eavesdropping, such as the addition of oxygen reactive layers. This invention also incorporates means for establishing security settings, profiles, and responses for the in-circuit security system and enrolled individuals. The in-circuit security system can be used in a variety of electronic devices, including handheld computers, secure facility keys, vehicle operation/ignition systems, and digital rights management.

Description:
RELATED U.S. APPLICATION DATA 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/555,480, filed Sep. 8, 2009, entitled “An In-Circuit Security System And Methods For Controlling Access To And Use Of Sensitive Data,” which is a divisional of U.S. patent application Ser. No. 10/858,287 (now U.S. Pat. No. 7,587,611), filed Jun. 1, 2004, entitled “An In-Circuit Security System And Methods For Controlling Access To And Use Of Sensitive Data,” which claims priority under U.S.C. §119(e) of provisional patent application Ser. No. 60/474,750, filed May 30, 2003, entitled “Secure Biometric Identification Devices and Systems for Various Applications,” each of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention disclosed herein relates to the security of sensitive data stored, processed and distributed using electronic circuits. More particularly, the invention relates to the identification of individuals prior to accessing/using data, and the execution of security controls upon unauthorized attempts to access/use said data. 
         [0004]    In recent years there has been an explosion of electronic devices that individuals may use for storing and transmitting sensitive data. In a low-security example, portable devices like a Palm™ or BlackBerry handheld computer typically contain software for e-mail, along with options for storing credit cards, schedules, and other data. Most people wish to protect this information, but most handheld devices rely on their operating system to secure data. Unfortunately, the most common operating systems for these handheld computers were not designed with security as the main goal, and retrofitting basic security mechanisms has been clumsy. 
         [0005]    A growing number of electronic devices, such as smart cards, are intended to specifically identify and authenticate users using the public key infrastructure, which requires secure storage of private keys. These devices are common in building security; for example, an individual with proper authorization to access a facility is assigned a smart card and an asymmetric key pair. A certificate authority generates a digital certificate for the public key, which is stored in the smart card. The private key is also stored on the smart card. When the individual places his smart card in the reader at the access point of the facility, the card transmits its digital certificate, and the reader challenges the card to encrypt a supplied string with the individual&#39;s private key. The reader obtains the public key out of the digital certificate and decrypts the private key-encrypted string to verify that the keys are related. This has an inherent problem because there is no guarantee that the individual using the private key is the assigned owner of the smart card. Furthermore, it is fairly simple for an experienced attacker to gain access to keys stored on the card. 
         [0006]    Some handheld devices, such as Hewlett Packard&#39;s iPAQ PocketPC h5450, include biometric sensors for improved personal identification before allowing access to sensitive data. An individual possessing this device is instructed to enroll one or more of his fingerprints into the device&#39;s software. The enrolled fingerprint can be used as the sole password or as an alternative to a typed password. This type of device can be a substantial improvement on traditional data-access methods, because the biometric can be definitively tied to a single individual. However, if the sensitive data is stored or transmitted insecurely, the biometric authentication does not substantially hinder an attacker from probing the memory and compromising it. 
         [0007]    These concerns have contributed to the marketing of products billed as ‘secure memory’ or ‘secure processor’. These products are typically constructed with varying degrees of security; one lower degree is considered ‘tamper-evident’, in which an unskilled observer would see that someone had attempted to maliciously gain access to secured data. A higher level is ‘tamper-resistant’, in which the product actively resists tampering by use of a self-destruct mechanism, an impermeable substance that coats the components storing sensitive data such as a polymer-based coating or other so-called “conformal coating”, or some other process. Furthermore, these products may encrypt input/output lines, mislabel parts, and perform other types of obfuscation. 
         [0008]    2. Description of the Related Art 
         [0009]    U.S. Pat. No. 5,533,123 to Force, et al., discloses programmable distributed personal security inventions. The patent teaches a “Secured Processing Unit” (“SPU”) comprising an “SPU chip” and a microprocessor designed especially for secure data processing. The invention integrates keys, encryption and decryption engines, and algorithms in the SPU of the invention. Purportedly, the security process is portable and easily distributed across physical boundaries. The invention is based upon three interdependent subsystems. The first subsystem of the invention is a detector subsystem, which alerts an SPU to the existence and to the character of a security attack. A second subsystem is a filter subsystem that correlates data from multiple detectors, then assesses the severity of the attack against the risk to the SPU&#39;s integrity, both to its secret data and to the design of the SPU itself. A third subsystem is a response subsystem for generating responses, or countermeasures, calculated by the filters to be most appropriate under the circumstances, in order to deal with the attack(s) detected. Force does not disclose identity credential verification within the SPU. 
         [0010]    U.S. Pat. No. 5,825,878 to Takahashi discloses a secure embedded memory management unit for a microprocessor. A microprocessor memory management apparatus is used for encrypted instruction and data transfer from an external memory. Physical security is obtained by embedding the direct memory access controller on the same chip with a microprocessor core, an internal memory, and encryption/decryption logic. Data transfer to and from an external memory takes place between the external memory and the memory controller of the memory management unit. All firmware to and from the external memory is handled on a page-by-page basis. Since all of the processing takes place on buses internal to the chip, detection of clear unencrypted instructions and data is prevented. Takahashi does not disclose any capability, anticipation, intention, or provision for including identity credential verification on the management unit or within the microprocessor core. 
         [0011]    U.S. Pat. No. 5,832,207 to Little, et al., teaches a secure module including a microprocessor and a co-processor. The electronic module is provided with at least one microprocessor and a co-processor deployed into a single integrated circuit. The electronic module can be contained in a small form factor housing. The electronic module provides secure bi-directional data communication via a data bus. The electronic module may include an integrated circuit including a microprocessor and a co-processor adapted to handle 1,024-bit modulo mathematics primarily aimed at RSA calculations. The electronic module is preferably contained in a small token-sized metallic container. The module preferably communicates via a single wire data bus using a one-wire protocol. Little et al. does not disclose personal identification systems. 
         [0012]    U.S. Pat. No. 5,894,550 to Thireit discloses a method of implementing a secure program in a microprocessor card, and a microprocessor card including a secure program. The invention claims that a program can be made secure relative to a CPU. The invention accomplishes this by storing in a first memory zone predetermined address functions that are directly executable by the CPU. The first memory zone is then write-protected, then the program is stored in a second memory zone in the form of a series of instructions that are executable within the second memory zone or that activate functions contained in the first memory zone. 
         [0013]    U.S. Pat. Nos. 5,481,265, 5,729,220, 6,201,484 and 6,441,770 to Russell detail a handheld device used to authenticate persons and said device to remote computer systems. The invention further includes a “kill switch” or “kill signal” enabling the computer system to remotely disable the handheld device and restrict further emissions. However, the system is primarily targeted at local area network applications and does not anticipate or suggestion broader applications. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    The invention disclosed herein is an in-circuit security system for electronic devices. The in-circuit security system incorporates identity credential verification, secure data and instruction storage, and secure data transmission capabilities. It comprises a single semiconductor chip, lowering component cost and reducing board space. The in-circuit security system chip is secured using mechanisms for preventing information tampering or eavesdropping, such as the addition of oxygen reactive layers. This invention also incorporates means for establishing security settings and profiles for the in-circuit security system and enrolled individuals. The in-circuit security system can be used in a variety of electronic devices, including handheld computers, secure facility keys, vehicle operation/ignition systems, and digital rights management. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Master Reference Numeral List 
         [0015]      FIG. 1 : Sample embodiment of in-circuit security system components 
           [0016]      100  In-circuit security system 
           [0017]      101  Processor 
           [0018]      102  Memory 
           [0019]      103  Identity credential verification subsystem 
           [0020]      104  Cryptographic subsystem 
           [0021]      105  Real-time clock 
           [0022]      106  Power source (OPTIONAL) 
           [0023]      107  Transceiver (OPTIONAL) 
           [0024]      108  Random number generator 
           [0025]      110  Connection to identity credential sensor 
           [0026]      111  Connection to peripheral components 
           [0027]      112  Connection to antenna or cables 
           [0028]      FIG. 2 : Handheld computer with the in-circuit security system 
           [0029]      100  In-circuit security system 
           [0030]      201  Non-secure processor 
           [0031]      202  Non-secure memory 
           [0032]      203  Fingerprint sensor 
           [0033]      204  Antenna 
           [0034]      213  Display 
           [0035]      214  Keypad 
           [0036]      FIG. 3 : Electronic lock mechanism with the in-circuit security system 
           [0037]      100  In-circuit security system 
           [0038]      313  LEDs 
           [0039]      314  Electronic lock mechanism 
       
    
    
       [0040]      FIG. 1  is a schematic view of a sample embodiment of the in-circuit security system. 
         [0041]      FIG. 2  is a schematic view of the components of a sample handheld computer using the in-circuit security system. 
         [0042]      FIG. 3  is a schematic view of the components of an electronic lock mechanism using the in-circuit security system. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    The invention described herein is an in-circuit security system by which pre-enrolled individuals may access sensitive data or perform actions on sensitive data in an environment that is fully monitored and protected. The in-circuit security system requires full authentication of individuals and can perform a variety of programmed responses in the event that pre-established authentication standards are not met. The in-circuit security system includes secure transmission of sensitive data to remote devices. 
         [0044]    The in-circuit security system comprises several components combined securely into a single, secure chip. As seen in  FIG. 1 , the primary embodiment of the in-circuit security system  100  comprises a processor  101 , a memory  102 , a real-time clock  105 , and a random number generator  108 . The in-circuit security system  100  also includes a cryptographic subsystem  104  and an identity credential verification subsystem  103 . These subsystems may be logical, physical, or some combination thereof, and are described in further detail below. In typical embodiments, the in-circuit security system  100  will also contain a power source  106 , such as a battery, in order to maintain power to the real-time clock  105 . During manufacture, the in-circuit security system  100  receives a unique, one-time programmable electronic identification code that can be read but cannot be altered or removed. The in-circuit security system  100  also preferably provides multiple input/output interfaces  110 - 112  for connection to optional internal/external components, such as transceivers  107 , antennae, identity credential sensors, non-secure processors, etc. 
         [0045]    The processor  101  is the main control component; it is responsible for loading and executing instructions to control the various components of the chip, as well as performing user- requested tasks. The memory  102  is coupled to the processor  101 . It comprises both volatile and non-volatile components and can be used to store instructions or data, such as security settings or profiles and cryptographic keys. The application of these security settings is discussed below. The real-time clock  105  is also coupled to the processor  101  and is used to maintain an accurate time, which can be used in cryptographic signing, audit records, or other transactions. The real-time clock  105  may be connected to a power source  106  in order to constantly maintain time. If the in-circuit security system  100  does not include the power source  106 , the real-time clock  105  must be cognizant of power disconnects, which means that it can no longer provide an accurate time. 
         [0046]    The fourth component of the in-circuit security system  100  is a random number generator  108 . The random number generator  108  is used for seeding cryptographic algorithms, and may use any of established methods for guaranteeing sufficient randomness. The random number generator  108  may be included as part of the cryptographic subsystem  104  or may be a standalone component coupled to the subsystem  104 . The cryptographic subsystem  104  is a dedicated system for performing encryption and decryption, digital signing and digital signature verification. In one embodiment the subsystem  104  is responsible for storing cryptographic keys in its own memory; in another, the subsystem is coupled to and uses the main memory  102  of the in-circuit security system  100 . Additionally, one primary embodiment of the invention uses a cryptographic acceleration chip or component as the cryptographic subsystem  104 . Alternative embodiments are coupled to and use the main processor  101  as the cryptographic engine. 
         [0047]    The identity credential verification subsystem  103  is used to determine the identity of an individual attempting to use the in-circuit security system  100  and identify his associated security privileges. The identity credential verification subsystem  103  performs identity credential acquisition, analysis, storage and matching. In the primary embodiment of the invention, the identity credential verification subsystem  103  uses digital representations of fingerprints as the identity credential. In this embodiment the identity credential verification subsystem  103  performs fingerprint image acquisition, and template generation, storage, and matching. The identity credential verification subsystem  103  may use the main processor  101  of the in-circuit security system  100  for credential processing actions or may use its own specialized processor. Similarly, it may employ its own memory for credential storage or use the main memory  102  of the in-circuit security system  100 . The in-circuit security system  100  provides one or more connections  110  to external components for credential sensing, such as a fingerprint sensor. 
         [0048]    The in-circuit security system  100  incorporates an interface  112  to a transceiver  107 , antenna, wire, or other remote communication device that is coupled to the processor  101 . This component is used for transmission of data from one device to another. All sensitive data that is to be transmitted from the in-circuit security system  100  can be encrypted using the cryptographic subsystem  104 , so it is not necessary to place a transceiver  107  within the secure boundaries of the in-circuit security system  100 . However, in some embodiments it may prove to be convenient to incorporate the transceiver  107  into the chip. In these embodiments the interface  112  would be from the transceiver to an antenna, wire, or other communication device. In a primary embodiment of the invention, the transmission technology is radio-frequency identification (RFID), such as the ISO 14443 A/B or 15693 standards. In another embodiment the in-circuit security system  100  uses Bluetooth or infrared technology. Other embodiments provide a combination of these technologies or others. In alternative embodiments, it may be useful to use a wired technology, such as a serial or USB connection. The in-circuit security system  100  preferably provides external connections  112  for requisite connectors, cables or antennae. 
         [0049]    The authentication of individuals allows the in-circuit security system  100  to associate an individual with specific security privileges within the system. For example, one user may be enrolled and identified as a typical user with no ability to reset the system  100 , while an alternate user may be identified as an administrator with that ability. Additionally, the in-circuit security system  100  may be programmed to perform a variety of both temporary and permanent responses to security events. For example, a specified number of access denials within a particular time interval may cause the in-circuit security system  100  to suspend all actions or halt the real-time clock  105  until reset by an enrolled administrator. Alternatively, an attempt to crack open the case of the chip housing the in-circuit security system  100  may result in permanent erasure of memory  102 , or destruction of other components. The in-circuit security system  100  may also be programmed to allow an enrolled individual to directly disable or destroy components. 
         [0050]    As described above, the in-circuit security system  100  is combined into one secured chip with three major interfaces: an interface to a credential sensing mechanism, such as a fingerprint sensor; an interface to peripheral components, such as non-secure processors or user-interface devices; and an interface to a transceiver or antenna for remote communications. Other interfaces are strictly prevented. The chip may use one or more physical security measures to prevent information eavesdropping. These obfuscation techniques include use of “potting”, oxygen-reactive layers, photo-sensors, Hall effect sensors, and circuits that monitor clock frequency and/or reset frequency. 
         [0051]    The system  100  may additionally perform algorithmic analysis of interface traffic. For example, fingerprint images received from a fingerprint sensor may be analyzed by the identity credential verification subsystem  103 ; if the identity credential verification subsystem  103  repeatedly receives the exact same bit pattern representation of fingerprints, it is possible that someone is deliberately placing that bit pattern on the interface. Similarly, if the identity credential verification subsystem  103  receives bit patterns that are an exact rotation or other permutation of a previously received image, again someone may be altering the contents of the interface. 
         [0052]    The in-circuit security system can be used as a standalone component for security applications or as one of multiple components within an electronic device. In one use of the invention, a handheld computer is equipped with the in-circuit security system  100 , as seen in  FIG. 2 . The computer further comprises a display  213 , a keypad  214 , a non-secure processor  201  and memory  202 , and a fingerprint sensor  203 . Additionally, for embodiments in which the in-circuit security system  100  includes a transceiver  107  that uses cellular wireless technology, the handheld computer also incorporates an antenna  204 . 
         [0053]    The primary user of the handheld computer enrolls a fingerprint, a digital certificate, and an associated private key into the in-circuit security system  100 . The fingerprint is stored in the identity credential verification subsystem  103  and is used to authorize use of the private key associated with the digital certificate. The digital certificate may be stored in the cryptographic subsystem  104  or the main memory  102  of the in-circuit security system  100 . 
         [0054]    The individual typically uses the handheld computer to transmit and receive e-mail. He requires the in-circuit security system  100  to digitally sign his e-mail, which requires accessing the stored private key associated with his fingerprint. He selects his e-mail program, and types an e-mail for transmission using the keypad  214 . The keypad  214  is coupled to the processor  201 , which receives the data and creates an appropriate message packet for transmission. Once created, the message packet is sent to the in-circuit security system  100  for further processing. 
         [0055]    The processor  101  of the in-circuit security system  100  receives the message packet and analyzes the established security settings for transmission of e-mail. Because the in-circuit security system  100  is configured to require digital signing of e-mail prior to transmission, the individual must first authenticate his fingerprint to the identity credential verification subsystem  103 . The biometric authentication is required to prevent unauthorized users from encrypting e-mail with a private key that is not theirs. The processor  101  signals the identity credential verification subsystem  103  to wait for a new fingerprint sample from the fingerprint sensor  203 , and signals the non-secure processor  201  to provide a visual prompt to the user on the display  213 . After the user places his finger on the fingerprint sensor  203  it sends the new fingerprint image to the identity credential verification subsystem  103 . The identity credential verification subsystem  103  analyzes the image, generates a template, and compares it to the enrolled fingerprint template. If the two match, the identity credential verification subsystem  103  sends a signal to the processor  101  that the individual is authorized to use the stored private key. 
         [0056]    The processor  101  now sends the e-mail message to the cryptographic subsystem  104  and instructs the cryptographic subsystem  104  to sign the message. This typically involves generating a hash of the message and encrypting it with the private key. The cryptographic subsystem  104  may also include a timestamp generated by the real-time clock, the unique device identifier, or other data, prior to the hash. The cryptographic subsystem  104  now sends the signed e-mail message back to the processor  101 . The processor  101 , in turn, sends the signed e-mail to the cellular transceiver  107  for transmission to a remote recipient. 
         [0057]    In a second embodiment of the invention, the in-circuit security system  100  is embedded into an electronic door locking mechanism that is used to control access to a secure facility. As seen in  FIG. 3 , the system comprises the in-circuit security system  100  with a wired connection to the electronic door lock  314 , a fingerprint sensor  203 , and a series of light emitting diodes (LEDs)  313  that are used to provide visual feedback to the user. Individuals access the secure facility by demonstrating enrollment of their fingerprint into the in-circuit security system  100 . The security settings of the in-circuit security system  100  are configured to shut down the entire locking mechanism on a pre-specified number of failed attempts within a pre-specified time span. This is example of security parameters and settings that are stored within the memory  102 . 
         [0058]    An enrolled individual wishes to enter the facility. One LED  313  glows green, signaling that the fingerprint sensor  303  is ready. The individual places his finger on the sensor  203 , which generates a fingerprint image and sends it to the identity credential verification subsystem  103 . The identity credential verification subsystem  103  generates a fingerprint template and compares it to the enrolled fingerprints. The new fingerprint template matches an existing template, so the identity credential verification subsystem  103  sends the individual&#39;s unique identifier to the processor  101 . The processor  101  accesses the memory  102 , which stores security privileges associated with enrolled individuals. The individual who is currently authenticated is authorized to enter the secure facility alone, so the processor  101  sends a signal to the transceiver  107  to trigger the lock  314  to release. 
         [0059]    Now an individual who has not been pre-enrolled into the identity credential verification subsystem  103  attempts to enter the secure facility. The individual places his finger on the fingerprint sensor  203 , which sends an image of the fingerprint back to the identity credential verification subsystem  103 . The fingerprint is compared to all of the enrolled fingerprints, and no match is found because the individual is not enrolled. The identity credential verification subsystem  103  records the date, time, and other requisite characteristics of the failed access attempt, and flashes a red LED  313  to show that access has been denied. The identity credential verification subsystem  103  also notifies the appropriate process within the processor  101  that an access failure has occurred. 
         [0060]    The individual now tries another, un-enrolled finger. The identity credential verification subsystem  103  records the subsequent failure, and notifies the processor  101  that there has been another failure. When the number of failed attempts reaches the pre-established limit, the identity credential verification subsystem  103  again notifies the processor  101  that a failure has occurred. At this point, the processor  101  applies the security settings and places the electronic lock mechanism  314  in a state where it cannot be unlocked unless it is reset by a recognized authority; in a primary embodiment this would be implemented using a “fail-secure” lock and would involve disconnecting a power source. Alternative actions can occur to put the lock  314  into this state as necessary. The processor  101  may also put the identity credential verification subsystem  103  into a state where it does not accept new fingerprints, create images, or perform matching. As desired by the regulator of the secure facility, the processor  101  may instruct the identity credential verification subsystem  103  to delete any enrolled fingerprint images. These are all examples of programmable security settings. 
         [0061]    While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.