Abstract:
An active membrane creates a secure area around one or more devices. The active membrane forms a physical barrier between the encased secure area and an external environment. Linked to the membrane and acting as the sole interface between the secure area and the outside environment is a boundary interface. The boundary interface tunnels data to the secure area in a secure fashion. According to one embodiment of the present invention, the boundary interface utilizes symmetric and/or asymmetric cryptographic techniques to secure the data path. The boundary interface is also coupled to the active membrane, and upon the membrane sensing a breach of the membrane (thus signifying an intrusion of the secure area), the boundary interface can be configured to sever the data paths linking the secure area with the unsecured area as well as take other active steps to ensure that data within the secure area is not compromised.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention relate, in general, to systems and methods for data protection and particularly to enclosing secure systems in tamper resistant enclosures. 
         [0003]    2. Relevant Background 
         [0004]    Cryptography is, in its broadest sense, the art of hiding information. Historically cryptography referred to encryption, the process of converting ordinary information (plaintext) into unintelligible gibberish (i.e., ciphertext), and decryption, the reverse, moving from unintelligible ciphertext to plaintext. In modern times cryptography encompasses a wide range of technology and techniques. These include symmetric-key cryptography, public-key (also, more generally, called asymmetric key) cryptography, cryptographic primitives, and cryptanalysis. 
         [0005]    Cryptography utilizing symmetric and asymmetric-key cryptographic techniques employs a cipher and a key. A cipher is two or more algorithms that perform encryption and the reversing decryption. The detailed operation of a cipher is controlled both by the algorithm and, in each instance, by a key. This is a secret parameter (ideally, known only to the communicants) for a specific message exchange context. Keys are important, as ciphers without variable keys are trivially breakable and therefore less than useful for most purposes. Thus the protection of the keys, and to some extent the algorithms themselves, is an important part of data security. 
         [0006]    A typical cryptographic system includes a secure environment housing the cryptographic algorithm(s) and, in the case of a public-private key pair, the private key. Received encrypted data generated by the related public key can be decrypted using the private key. The private key must remain secret while the public key can be freely distributed. 
         [0007]    As will be appreciated by one skilled in the art of cryptography, many systems exist to securely manage cryptographic keys. One aspect of that management is the security of the keys and other cryptographic material to what is known in the art as an insider attack. An insider attack is an attack or intrusion from an entity that is trusted. This entity, having direct access to the system, can replace or insert devices in the middle of the data path to capture data and/or the keys. 
         [0008]    This type of intrusion is generally addressed by maintaining complete physical security of the device and wires that contain and transport the data or by protecting the data cryptographically. Many systems are, however, incapable of, or it is infeasible to support, data cryptography. Thus physical security becomes the primary means to ensure that the cryptographic keys remain secure. 
         [0009]    Current boundary protection is either tamper resistant or tamper evident. Tamper evident techniques simply present evidence that a device or system has been tampered with and thus the contents can no longer be trusted. Tamper resistant protection is understood to mean that intrusion into the device will result in damage making the device nonfunctional. One simple tamper resistant technique is to seal the components in epoxy. Many cryptographic functions and keys can be hard wired into an integrated circuit or the like. If one could examine the circuit, the key and algorithms would be revealed. Thus encasing the chip in epoxy prevents reverse engineering because removal of the epoxy would theoretically destroy the enclosed components. 
         [0010]    This type of physical barrier however is not fool proof. While penetrating a chip using a barrier of this type is likely to render it non-functional, portions of the technology within the barrier may be recoverable. Furthermore, this type of barrier fails to protect an intrusion into the data path. The current art does not provide a cryptographically secure interface that is sensitive to physical intrusion. 
       SUMMARY OF THE INVENTION 
       [0011]    The present invention provides systems and methods for creating a tamper resistant enclosure for secure systems. According to one embodiment of the present invention, a boundary interface is coupled to an active membrane to form a tamper resistant enclosure. The boundary interface is linked to the active membrane such that upon an intrusion of the membrane or breach of the membrane, the boundary interface acts to protect the confidential data maintained within the enclosure. 
         [0012]    The features and advantages described in this disclosure and in the following detailed description are not all-inclusive; many additional features and advantages will be apparent to one of ordinary skill in the relevant art in view of the drawings, specification, and claims hereof. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the inventive subject matter; reference to the claims is necessary to determine such inventive subject matter. 
         [0013]    According to one embodiment of the present invention, an active membrane is configured to create a secure area around one or more unsecured devices. The active membrane forms a physical barrier between the secure area and an unsecured area and is configured to sense a breach of the membrane. Linked to the membrane and acting as the sole interface between the interior secure area and the outside unsecured area is a boundary interface. The boundary interface tunnels data to the secure area in a secure fashion. According to one embodiment of the present invention, the boundary interface utilizes symmetric and asymmetric cryptographic techniques to secure the data path. The boundary interface is also coupled to the active membrane, and upon the membrane sensing a breach of the membrane (thus signifying an intrusion of the secure area), the boundary interface can be configured to sever the data paths linking the secure area with the unsecured area. 
         [0014]    In another embodiment of the present invention, sensing a breach of the membrane can trigger the boundary interface to destroy confidential data maintained within the secure area. According to another aspect of the invention, the keys used to encrypt and decrypt the data along the data pathway can be changed or zeroed. Based on an indication that the physical security of the secure area has been compromised, the boundary interface acts to protect the security of the material within the secure environment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The aforementioned and other features and objects of the present invention and the manner of attaining them will become more apparent, and the invention itself will be best understood, by reference to the following description of a preferred embodiment taken in conjunction with the accompanying drawings, wherein: 
           [0016]      FIG. 1  shows a high level block diagram according to one embodiment of the present invention for a tamper resistant environment for secured systems; 
           [0017]      FIG. 2  shows a block diagram of components included within a boundary interface according to one embodiment of the present invention; and 
           [0018]      FIG. 3  is a flowchart showing one method embodiment for securing data and/or devices within a tamper resistant enclosure, according to the present invention. 
       
    
    
       [0019]    The Figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    A secure environment formed by combining an active membrane and a boundary interface is hereinafter described. A secure enclosure is created by an active membrane that is physically and communicatively coupled to a boundary interface. The active membrane is configured to sense and communicate any type of intrusion into the secured enclosure. Any breach of the membrane is sensed and communicated to the boundary interface. Upon receiving an indication that the secured enclosure is no longer physically intact, the boundary interface acts to maintain the security of the components and data contained within the environment. 
         [0021]    Specific embodiments of the present invention are hereafter described in detail with reference to the accompanying Figures. Like elements in the various Figures are identified by like reference numerals for consistency. Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention. 
         [0022]      FIG. 1  provides a high level block representation of a tamper resistant environment for secure systems according to one embodiment of the present invention. The tamper resistant system  100  comprises an active membrane  110  and a boundary interface  120 . The combination of the membrane  110  and the interface  120  forms a secure environment  130  within which a plurality of unsecured devices  140  can exist without fear of external intrusion. As will be appreciated by one skilled in the relevant art, the unsecured devices  140  can also include secured devices. In such an architecture the present invention provides an additional layer of security. Unsecured devices  140  can include databases, processors, various forms of memory media, and other components that require a tamper resistant environment. These unsecured devices  140  are communicatively coupled to components and systems outside of the secure environment  130  via a plurality of data paths  150  that traverse the boundary interface  120 . 
         [0023]    The boundary interface  120  is the sole interface between the unsecured devices  140  existing within the tamper resistant environment and the outside environment.  FIG. 2  shows, according to one embodiment of the present invention, components within the boundary interface that facilitate the creation and maintenance of the tamper resistant environment. The boundary interface  120  includes, in one embodiment of the present invention, a memory  210 , a processor  220  or some device capable of execution instruction embodied as software, and cryptographic key(s)  230 . 
         [0024]    The memory can be in the form of various storage media and is, at least in one embodiment of the present invention, non-volatile. Portions of software code controlling the data paths between the secure environment  130  and the outside environment can be maintained in the memory  210 . This can include various cryptographic algorithms as would be known to one skilled in the cryptographic arts. The memory  210  can also include software portions that can direct the boundary interface  120  to sever the links between the secure environment  130  and the outside world. It can also direct keys held in memory to be zeroed or changed. Furthermore it can contain instruction to be conveyed to the unsecured devices  140  to destroy or erase their contents. The processor  220 , or similar device capable of executing executable code, retrieves the code and executes the instructions facilitating securing the devices  140  and information contained within the secure environment. 
         [0025]    When cryptographic techniques are used to secure the data paths, the processor  220  retrieves and executes various cryptographic algorithms stored in memory  210  as well as the necessary keys stored in a separate storage location  230 . The keys are, in one embodiment of the present invention, stored in volatile memory so as to further enhance their ability to be zeroed or destroyed upon a breach of the membrane  110 . 
         [0026]    To better illustrate the novel features of the present invention, consider the following example. Assume that a plurality of devices are identified as in need of operating within a secure, tamper resistant environment. These devices may be in communication with one another or operate independently. In addition to these devices is a boundary interface. Each device or group of devices communicates to entities outside of the environment through the boundary interface. The boundary interface and each of the devices are surrounded by an active membrane that is communicatively coupled to the boundary interface. The active membrane is a casing that can sense a physical intrusion. The act of tearing, puncturing, or destroying the membrane results in a signal that is, in this case, conveyed to the boundary interface. 
         [0027]    The data paths exiting the boundary interface traverse the active membrane. The data and communications that are exchanged via these external data paths are secured by the boundary interface. The boundary interface encrypts data coming from the devices within the membrane prior to its exit from the secure environment using a cryptographic technique. Similarly, encrypted data that is incoming is decrypted by the boundary interface prior to being delivered to a device within the environment. In another embodiment data coming into the boundary interface can be encrypted by the boundary interface and stored in the secure environment in its encrypted form. 
         [0028]    When the active membrane senses an intrusion of some type a signal is sent to the boundary interface. The boundary interface can react to this intrusion in a number of ways. The key stored in the boundary interface can be zeroed. Once zeroed, the data that was previously encrypted by the interface and stored within the membrane will remain secure. Similarly the links between the boundary interface and the external environment can be severed to prevent additional incoming data from being compromised. The boundary interface can also act to destroy data maintained within the secure environment on one or more of the devices. 
         [0029]    Since the boundary interface is within the secure environment, an attempt to compromise the boundary interface will also result in a sensed intrusion by the membrane and initiate the data protection steps outlined above. 
         [0030]      FIG. 3  is a flowchart illustrating methods of implementing an exemplary process for securing a device or data within a tamper resistant enclosure. In the following description, it will be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be loaded onto a computer or other programmable apparatus to produce a machine such that the instructions that execute on the computer or other programmable apparatus create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable apparatus to function in a particular manner such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable apparatus to cause a series of operational steps to be performed in the computer or on the other programmable apparatus to produce a computer implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. 
         [0031]    Accordingly, blocks of the flowchart illustrations support combinations of means for performing the specified functions and combinations of steps for performing the specified functions. It will also be understood that each block of the flowchart illustrations, and combinations of blocks in the flowchart illustrations, can be implemented by special purpose hardware-based computer systems that perform the specified functions or steps, or combinations of special purpose hardware and computer instructions. 
         [0032]    As shown in  FIG. 3  the process begins  305  with the encasement  310  of a plurality of devices and a boundary interface by an active membrane to form a secure environment. The active membrane is communicatively coupled to the boundary interface. The devices may themselves be storage media for the storage of data. External communication links are established  320  with each device within the secure environment via the boundary interface. 
         [0033]    Once the membrane is in place the integrity of the membrane is continuously monitored  330 . The boundary interface as the sole link between the devices encased by the membrane and the external environment forms  340  a plurality of secure data paths using at least one cryptographic technique. Upon the active membrane sensing  350  an intrusion or breach of the membrane a signal is sent from the membrane to the boundary interface. The boundary interface then takes active steps  360  to protect the security of the devices and content within the secure environment ending the process  395 . These steps can include severing the data paths, zeroing encryption/decryption keys, destroying or causing the destruction of data maintained within the environment, or any similar steps that ensure that the security of the devices or content held within is not compromised. 
         [0034]    Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention. The particular naming and division of the modules, managers, functions, systems, engines, layers, features, attributes, methodologies, and other aspects are not mandatory or significant, and the mechanisms that implement the invention or its features may have different names, divisions and/or formats. Furthermore, as will be apparent to one of ordinary skill in the relevant art, the modules, managers, functions, systems, engines, layers, features, attributes, methodologies, and other aspects of the invention can be implemented as software, hardware, firmware or any combination of the three. Of course, wherever a component of the present invention is implemented as software, the component can be implemented as a script, as a standalone program, as part of a larger program, as a plurality of separate scripts and/or programs, as a statically or dynamically linked library, as a kernel loadable module, as a device driver, and/or in every and any other way known now or in the future to those of skill in the art of computer programming. Additionally, the present invention is in no way limited to implementation in any specific programming language, or for any specific operating system or environment. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.