Patent Publication Number: US-9420008-B1

Title: Method for repurposing of communications cryptographic capabilities

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. Provisional Application Ser. No. 61/645,169, filed May 10, 2012; the disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The current invention relates generally to apparatus, systems and methods for securing data. More particularly, the apparatus, systems and methods relate to securing data in an electronic warfare (EW) environment. Specifically, the apparatus, systems and methods provide cryptographic services to systems that do not have cryptographic services in an EW environment. 
     2. Description of Related Art 
     Many systems such as those that participate in electronic warfare (EW) or identification of friend or foe (IFF) may need to encrypt and/or decrypt data. Alternatively they may require initialization vectors (IVs) used to begin encrypting data or for the generation of secure keys. Alternatively some EW systems may require other secure data. For example, a time to switch communication frequencies so that an enemy cannot intercept EW communications. Generation of these types of data requires each EW device to have the capability to generate cryptographic functions. The costs of embedding cryptographic devices in those devices may be prohibitive, or their architecture may not be supportive of such secure cryptographic devices. What is needed is a better way to generate cryptographic functions in devices in an EW environment. 
     SUMMARY 
     According to the preferred embodiment, many communication (Comms) systems have embedded cryptographic devices and can be directly interfaced with other systems on a platform such as those used in an electronic warfare (EW) environment that may need to identify friend or foe (IFF). By exposing an interface to those embedded cryptographic devices (i.e. offering a set of “cryptographic services”) it becomes possible for external systems (EW, IFF etc.) to perform functions requiring cryptographic services without having embedded cryptographic capability in every device. An example would be a ground mobile radio (GMR) or similar radio encrypting/decrypting information for a Counter Radio Controlled Improvised Explosive Device Electronic Warfare (CREW) system or Joint CREW (JCREW) system so that it can transmit encrypted data as embedded data in an EW environment. This invention can also be used to provide “reception security” to randomize the location of EW quiet periods. 
     One configuration of the preferred embodiment is a method for repurposing of cryptographic capabilities in an electronic warfare (EW) environment. The method begins by determining in a client system a cryptographic function that needs to be performed; however, the client system does not have any cryptographic functionality. The client system may, for example, be a CREW system used to deactivate improvised explosive devices (IEDs). The client system then requests the cryptographic function be performed in a cryptographic logic that is physically secured with the client system and is external to the client system. The cryptographic logic may, for example, be located in a GMR system. The cryptographic logic performs the cryptographic function to produce a cryptographic result. The cryptographic result is then provided to the client system. 
     In another configuration of the method, the client system is a first client system, the cryptographic logic is a first cryptographic logic, the cryptographic function is a first cryptographic function and the cryptographic result is a first cryptographic result. The method transmits the first cryptographic result from the first client system to a second client system. The second clients system then requests that a second cryptographic function be performed in a second cryptographic logic. The second cryptograph logic may be physically secured with the second client system and may be external to the second client system. The second cryptographic function is performed in the second cryptographic logic to produce a second cryptographic result. The second cryptographic result is then provided to the second client system. 
    
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       One or more preferred embodiments that illustrate the best mode(s) are set forth in the drawings and in the following description. The appended claims particularly and distinctly point out and set forth the invention. 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale. 
         FIG. 1  illustrates an electronic warfare (EW) environment in which repurposing of cryptographic capabilities is useful. 
         FIG. 2  illustrates an example schematic diagram of some components in an EW environment implementing the preferred embodiment of a system for repurposing of cryptographic capabilities. 
         FIG. 3  illustrates another example schematic diagram of another configuration of some components in an EW environment implementing the preferred embodiment of a system for repurposing of cryptographic capabilities. 
         FIG. 4  illustrates an embodiment of a method for repurposing of cryptographic capabilities in an EW environment. 
     
    
    
     Similar numbers refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION 
     As mentioned above, devices used in an electronic warfare (EW) type of environment may need cryptographic capabilities but it can be cost prohibitive to implement that capability separately in each device. For example,  FIG. 1  illustrates an example vehicle  1  used in an EW battlefield. The vehicle illustrated is a Humvee but it could be a different vehicle or any other device that requires cryptographic capability. For example, the vehicle in  FIG. 1  can be outfitted with a Counter Radio Controlled Improvised Explosive Device Electronic Warfare (CREW) system  3 . The CREW system  3  can be a joint CREW (JCREW) or a Duke type of system that is used to disable improvised explosive devices (IEDs). 
     The CREW system  3  has IED countermeasure logic  5  and an antenna  7  electrically connected to the IED countermeasure logic  5 . The IED countermeasure logic  5  rapidly generates a variety of frequencies over a band of frequencies that it desires to jam and radiates them out of the antenna  7  at high power. The frequencies or band of frequencies would correspond to possible frequencies that a terrorist would use to signal to an IED that it is to detonate. The CREW system  3  should generate these jamming frequencies of sufficient power so that as the vehicle approaches the IED it is disabled at a sufficient distance away from the vehicle  1  before the vehicle  1  of  FIG. 1  and any other vehicles traveling with it are too close to the IED if it were to detonate. Of course, these jamming frequencies should also be of sufficient power so that the vehicle  1  of  FIG. 1  and any other vehicles traveling with it are at a sufficient distance past the IED when the CREW system  3  can no longer disable the IED. 
     While the CREW system  3  is primarily used in disabling IEDs, it may perform other operations. For example, it may want to send classified operational statistics or other classified data from the vehicle  1  into a wireless electronic warfare network. However, to do this it would need to be outfitted with costly encryption logic, decryption logic and other logic needed to implement the required cryptographic capability. Rather than implement this cryptographic functionality in the CREW system  3 , as discussed below the preferred embodiment of the invention takes advantage of using the cryptographic capability of the communication system  9  implemented in the vehicle  1 . The communication system  9  communicates with the CREW system  3  over a bus  10 . The communication system  9  could be a ground mobile radio (GMR) or similar radio or another device capable of encrypting/decrypting information for a CREW or JCREW system so that it can be transmitted as encrypted embedded data in an EW environment. As discussed later, the preferred embodiment can also be used to provide “reception security” to randomize the location of EW quiet periods. 
     “Logic”, as used herein, includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. For example, based on a desired application or needs, logic may include a software controlled microprocessor, discrete logic like an application specific integrated circuit (ASIC), a programmed logic device, a memory device containing instructions, or the like. Logic may include one or more gates, combinations of gates, or other circuit components. Logic may also be fully embodied as software. Where multiple logics are described, it may be possible to incorporate the multiple logics into one physical logic. Similarly, where a single logic is described, it may be possible to distribute that single logic between multiple physical logics. 
       FIG. 2  illustrates some of the components used in a method of repurposing cryptographic capabilities. The primary components of this figure in a first client system  11 A and a second client system  11 B as well as a first communication system (comms system)  13 A and a second communication system  13 B. The first client system  11 A may be the CREW system  3  of  FIG. 1  and the first communication system  13 A may be a communication system  9  located in a vehicle  1 . 
     Each communication system  13 A,  13 B has a corresponding cryptographic logic (crypto service)  15 A,  15 B. In this example figure, the first client system  11 A is connected to the first communication system  13 A with a first red bus  17 A and the second client system  11 B is connected to the second communication system  13 B with a second red bus  17 B. Here the term “red” bus indicates that it is a secure bus. For example, this bus may act similar to a bus  9  of  FIG. 1  that allowed the CREW system  3  to communicate with the communication system  9  in the vehicle  1 . The bus  9  is secure because it is interior to the vehicle  1  and not accessible by an enemy/terrorist. The first and second red busses  17 A,  17 B would also likely be secured inside secure structures in whatever environment they are operating. 
     The cryptographic logic  15 A,  15 B can implement a block cypher. For example, the cryptographic logic  15 A,  15 B can implement the data encryption standard (DES), triple DES (3DES), the advanced encryption standard (AES) or another block cypher. The AES cypher can be configured to operate using 128, 192 and/or 256 bit keys. The cryptographic logic  15 A,  15 B can also be configured to implement hash functions. For example, a cyclic redundancy check (CRC), a checksum, a message digest (MD), a secure hash algorithm (SHA) and/or another hash algorithm can be implemented. The cryptographic logic  15 A,  15 B can also generate keys, initialization vectors (IVs), generate, other random numbers and/or perform other cryptographic functions. 
     Having introduced the components of  FIG. 2 , their use and operation will now be described. As mentioned earlier, the first client system  11 A may be the CREW system  3  of  FIG. 1  and the first communication system  13 A may be a radio system  9  located in a vehicle  1 . The second client system  11 B and second communication system  13 B may be in an electronic device, a vehicle, another unit or some other self-contained device located separately from the first client system  11 A and the first communication system  13 A. 
     In operation, the first client system  11 A may desire to send transmitted data  19  to the second client system  11 B over a network link  21 . However, it may be operating in an EW battlefield and the network link  21  may be a wireless link so that the data may need to be encrypted before it is transmitted. Additionally, the first client system  11 A may be a CREW type of system or another type of system and may not have the ability to perform cypher operations. In that case, the first client system  11 A can place the data for encryption  23  on the first secure first red bus  17 A to transfer it to the first communication system  13 A that has cryptograph logic  15 A. The first cryptographic logic  15 A then encrypts the data into encrypted data  25  and returns it to the first client system  11 A over the red bus  17 A. Alternatively a “black” (unsecure) interface can be used if it exists to return the encrypted data  25  to the first client system  11 A because the data is encrypted and cannot be read by an unauthorized user. 
     The first client system  11 A can now send the encrypted data  25  as the transmitted data  19  over the communication link  21  to the second client system  11 B. As illustrated, the second client system  11 B may also not have the ability to perform cryptographic functions. In that case, in order to decrypt the message the second client system  11 B can send the received transmitted data  19  as data for decryption  27  to the second communication system  13 B over the second red bus  17 B between them. Alternatively a “black” (unsecure) interface can be used if it exists to send the data for decryption  27  to the second communication system  13 B because the data is encrypted and cannot be read by an unauthorized user. The second communication system  13 B can then decode the data for decryption  27  using its cryptographic logic  15 B to produce decrypted data  29 . It can then return the decrypted data  29  to the second client system  11 B over the second red bus  17 B. The second client system  11 B can then respond to or take appropriate action based on the contents of the decrypted data  29 . 
       FIG. 3  illustrates the use of a bypass channel used in a method of repurposing cryptographic capabilities. Elements in  FIG. 3  with the same reference number are similar to the elements of  FIG. 2  with the same reference number. Many modern cryptographic systems are set up to be one-way. This means that data goes in the red sides  31 A,  31 B (secured side) of cryptographic logics  15 A,  15 B, and out the “black” (unsecured) sides  33 A,  33 B of the cryptographic logics  15 A,  15 B. In practice, modifying a cryptographic system to output data back on the red side  31 A,  31 B may be difficult and may require recertification of the cryptographic logic  15 A,  15 B and the like. An alternative approach is to feed the encrypted data  25  back and forth to the black side  33 A,  33 B on a “bypass channel”  41 A,  418  within the cryptographic logic  15 A,  15 B. This alternative would generally be used for control data, and may require some level of recertification for the system but this approach may be easier. As illustrated in  FIG. 3 , the encrypted data exits the black side  33 A of cryptographic logic  15 A and a black processor  43 A receives and then returns it to the black side  33 A so that it can be sent over the bypass channel  41 A and then on the red bus  17 A and back to the client system  11 A. As illustrated, the decrypted data  29  can similarly be routed over a bypass channel  41 B in the second communication system  13 B. 
     In still another alternate embodiment, the client systems  11 A,  11 B can request a defined number of random bits be placed on the red bus  17 A,  17 B. These random bits can provide an initialization vector (IV) and/or cryptographic key information and may be used for randomization or other purposes. In response to this request, the cryptographic logic  15 A,  15 B creates the requested bits and provides them on red bus  17 A,  17 B. 
     The block diagrams for illustrating when the cryptographic logic  15 A,  15 B performs other types of services are similar to those illustrated in  FIGS. 2 and 3  for data encryption and decryption. In  FIGS. 2 and 3 , for example, “Data for Encryption” is replaced by “Random Bits” when these figures represent the cryptographic logics  15 A, providing random bits. To represent the first cryptographic logic  15 A generating an initialization vector (IV) “Data for Encryption” is replaced by “IV”. To represent the first cryptographic logic  15 A generating a cryptographic key “Data for Encryption” is replaced by “Cryptographic Key”. These figures could be used to represent the first cryptographic logic  15 A performing other cryptographic functions by replacing “Data for Encryption” with the name of the result of that function. 
     A useful example of when one of the cryptographic logics  15 A,  15 B would be tasked to generate random bits involves determining modulation quiet periods in EW systems. EW systems periodically need to listen to the electromagnetic radiation (ER) spectrum for potential threat systems, and thus EW systems must synchronize quiet periods so that they all are quiet at the same time. Otherwise nonstop EW transmissions make it impossible to hear potential threats. Routine/periodic static quiet periods are vulnerable to exploitation. Threats can determine when periodic static quiet periods occur and suppress their own transmissions during quiet periods to remain undetected. Additionally, threats can transmit during quiet periods to intentionally mask other threats. 
     Thus, the quiet periods are randomized with the use of random numbers that are broadcast to all appropriate units in a battlefield. Randomized periods are less susceptible to exploitation. Algorithms such as used in system like Link 16 Joint Tactical Information Distribution System (JTIDS) or IEEE 802.11 can be used to make use of the random numbers to randomize frequency and start times of quiet periods. “Reception security” (RECSEC) bits may be used to define quiet period locations in time and frequency. Created time domain and/or frequency domain tiling structures such as used for Link 16 or multi-frequency-time division multiple access (MF-TDMA) systems may also “hop” the center frequency of quiet areas based on a set of random bits and may also “jitter” the start of a quiet period from the TDMA slot boundaries based on other random bits. Quiet times may also overlap slot boundaries. 
     Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity of explanation, the illustrated methodologies are shown and described as a series of blocks, it is to be appreciated that the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example methodology. Blocks may be combined or separated into multiple components. Furthermore, additional and/or alternative methodologies can employ additional, not illustrated blocks. 
       FIG. 4  illustrates a method  400  for repurposing of cryptographic capabilities in an electronic warfare (EW) environment. The method begins, at  402 , by determining in a client system a cryptographic function to be performed; however, the client system does not have any cryptographic functionality. The client system then requests, at  404 , the cryptographic function be performed in a cryptographic logic that is physically secured with the client system but is external to the client system. The cryptographic logic performs the cryptographic function, at  406 , to produce a cryptographic result. The cryptographic result is then provided to the client system, at  408 . 
     In another configuration of the method, the client system is a first client system, the cryptographic logic is a first cryptographic logic, the cryptographic function is a first cryptographic function and the cryptographic result is a first cryptographic result. The method transmits the first cryptographic result from the first client system to a second client system. The second clients system then requests that a second cryptographic function be performed in a second cryptographic logic. The second cryptograph logic may be physically secured with the second client system but be external to the second client system. The second cryptographic function is performed in the second cryptographic logic to produce a second cryptographic result. The second cryptographic result is then provided to the second client system. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. Therefore, the invention is not limited to the specific details, the representative embodiments, and illustrative examples shown and described. Thus, this application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims. 
     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. References to “the preferred embodiment”, “an embodiment”, “one example”, “an example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in the preferred embodiment” does not necessarily refer to the same embodiment, though it may.