Patent Publication Number: US-2017363767-A9

Title: Container defense system

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. patent application Ser. No. 12/596,971, filed Jul. 7, 2010 by Fred Hewitt Smith, and entitled “Container Defense System,” which is a U.S. National Stage of International Application No. PCT/2008/001350, filed Feb. 1, 2008, which claims the benefit of priority to U.S. Provisional Application No. 60/899,275 filed on Feb. 1, 2007, all of which are hereby incorporated herein by reference in their entirety. 
    
    
     SUMMARY 
     The inventors have realized that a system featuring low power, inexpensive scanners may be used to scan composite containers for the presence of nuclear weapons and certify the containers for future shipping. 
     In one aspect, a system for scanning and securing a container including a plurality of at least partially composite panels defining an interior volume is disclosed, the system including: a remote control unit; a receiver unit in communication with the remote control unit; a scanner including a beam generator adapted to emit a directed radiation scan beam and a detector adapted to detect the scan beam, the scanner in remote communication with the remote control unit; a beam detector element positioned within the container adapted to detect the scan beam; an intrusion detection system positioned within the container adapted to detect an intrusion into the container; an identification element positioned within the container and adapted to store identity information indicative of the identity of the container; a transmitter element positioned within the at least one container The e beam generator is adapted to direct the scan beam along a path into the interior volume of the container through one of the plurality of at least partially composite panels, across a portion of the interior volume, out of the interior volume through one of the plurality of at least partially composite panels, and onto the scan beam detector and the scanner is adapted to determine material property information indicative of the material properties of contents of the interior volume based on the detected beam. The scanner is adapted to modulate a query message from the remote control unit onto the scan beam, and the beam detector element is adapted to demodulate the message. The identification element is adapted produce a response message based on the demodulated query message and the stored identity information. The transmitter element is adapted to transmit the response message to the receiver unit. 
     In some embodiments, the remote control unit is adapted to receive the response message from the receiver unit and verify the identity of the container based on the verification response message. In some embodiments, the query message includes a number generated randomly by the remote control unit. 
     In some embodiments the remote control unit is adapted to determine the presence or absence of a nuclear device within the container based on the material property information and, if no nuclear device is determined to be present, store a certificate associated with the container. In some embodiments, the scanner is located in proximity to the receiver unit. 
     Some embodiments include: a dosimeter positioned within the at least one container, the dosimeter including a radon detection element adapted to detect a radon level for the interior volume; and a neutron detection element adapted to detect a neutron level for the interior volume. The dosimeter is adapted to measure the radon level and neutron level for a period of time, compare the measured radon level to a first threshold, compare the measured neutron level to a second threshold, determine dosimeter information indicative of the presence or absence of fissile material within the interior volume based on the comparisons, and communicate the dosimeter information to one or more of the identification element, the transmitter element, the receiver element, and the beam detector element. 
     In some embodiments, the identification element is adapted to destroy a portion of the stored identification information in response to an intrusion detected by the security element. 
     In some embodiments, the identification element is adapted to destroy a portion of the stored identification information in response to a detection of fissile material within the container by the dosimeter. 
     Some embodiments include a verification unit including a verification scanner including a beam generator adapted to emit a directed radiation verification scan beam; and a verification receiver unit located in proximity to the verification scanner unit. The verification scanner unit is adapted to modulate a verification query message received from the remote control unit onto the verification scan beam, and direct the verification scan beam to the beam detector element located within the container. The beam detector element is adapted to detect the verification scan beam and demodulate the verification query message. The identification is adapted produce a verification response message based on the demodulated verification query message and the stored identity information. The transmitter element is adapted to transmit a verification response message to the receiver unit. The remote control unit is adapted to receive the verification response message from the receiver unit and verify the identity of the container based on the verification response message. 
     Some embodiments include a loading device in communication with the remote control unit and located in proximity the verification unit, the loading device adapted to selectively load the at least one container onto a transport (e.g. a ship, train or truck) based on the verification of the and the of the certificate associated with the identity of the container. 
     In some embodiments, the identification element stores private identification information which cannot be transmitted to any scanner or receiver located outside the container. 
     In some embodiments, the security element includes a sensor grid embedded in one or more of the plurality of at least partially composite panels. 
     In some embodiments, the container includes a sealed container having a substantially air tight interior volume, and the security element includes a radon detector unit adapted to: detect the change in radon level in the interior volume of the sealed container; compare the detected change to an expected change value based on the four day half life of radon; and indicate the presence or absence of an intrusion into the sealed container based on the comparison. 
     Some embodiments include a first scanner adapted to produce a relatively low energy directed radiation scan beam; a second scanner adapted to produce a relatively high energy directed radiation scan beam; and a sorting module adapted to direct containers represented to contain substantially no metal material to the first scanner and to direct containers represented to contain metal material to the second scanner. The first scanner is adapted to receive a container represented to contain substantially no metal material from the sorting module, and to scan the container to verify that substantially no material is present inside the container. The second scanner is adapted to receive a container represented to contain metal material from the sorting module, and to scan the container to detect the presence of a nuclear device. Some such embodiments also include a third scanner adapted to produce a relatively moderate energy directed radiation scan beam. The sorting module is adapted direct containers represented to contain metal material which has a density above a threshold value to the second scanner, and to direct containers represented to contain metal material consisting only of metal material having a density below the threshold value to the third container. The third scanner is adapted to receive a container represented to contain metal material consisting only of metal material having a density below the threshold value from the sorting module, and to scan the container to verify that substantially no material is present inside the container having a density above the threshold value. 
     In some embodiments, the scanner and the receiver unit each include an information security element adapted to prevent access to data stored in the scanner and the receiver unit by an entity other than the remote control unit. 
     In another aspect, a method for scanning and securing a container including a plurality of at least partially composite panels defining an interior volume is disclosed, the method including: storing unique identification information in an identification element within container; sealing the container; monitoring the container for intrusion; without breaching the seal of the container, remotely identifying the container based on the unique identity information without breaching the seal of the container; without breaching the seal of the container; scanning the identified container to determine the presence or absence of a nuclear weapon in the interior volume; and if the scan determines no nuclear weapon is present, remotely storing certificate information associated with the identity of the container in a remote monitor unit. 
     In some embodiments, the storing unique identification information in an identification element within container includes: at a secure trusted location, providing identification information to be stored in the identification element positioned within the container, the identification information including a public ID portion and a corresponding secret ID portion, and storing a copy of the public ID and the private ID in the remote monitor unit. 
     In some embodiments, remotely identifying the container includes: at a first location, providing the remote monitor unit; at a second location providing a scanning unit in communication with the remote monitor unit, the scanning unit adapted to communicate with the identification element within the container without breaching the seal of the container; generating query information at the remote monitor unit; transmitting the query information to the remote scanning unit; without breaching the seal of the container transmitting the query information from the remote monitor to the identification element; at the identification element, using a hash algorithm to hash the query information with the private ID to produce response hash information; in response to the query information, without breaching the seal of the container, transmitting the public ID stored in the identification element and the response hash information to the scanning unit transmitting the public ID stored in the identification element and the response hash information from the scanning unit to the remote monitor unit; and at the remote monitor unit: identifying the private ID corresponding the public ID received from the scanning unit; using the hash algorithm to hash the query information with the identified private ID to produce verification hash information; comparing the response hash information to the verification hash information to verify the identity of the container. 
     Some embodiments include, in response to an intrusion of the container, modifying or destroying at least a portion of the identification information. 
     In some embodiments, the scanning includes: generating a directed radiation scan beam having a beam energy sufficient to penetrate through at least one of the plurality of composite panels but insufficient to penetrate through bulk metal material; directing the scan beam along a path into the interior volume of the container through one of the plurality of at least partially composite panels, across a portion of the interior volume, out of the interior volume through one of the plurality of composite panels, and onto a scan beam detector; detecting the scan beam with the scan beam detector, analyzing the detected beam to determine information indicative of the material properties of contents of the interior volume based on the detected beam; and outputting the information indicative of the material properties of contents of the interior volume. 
     Some embodiments include using a dosimeter positioned within the container to measure the radon level and the neutron level in the interior volume over a period of time, detecting the presence or absence of fissile material within the interior volume based on the measured radon level and neutral level; in response to a detection of fissile material, destroying a portion of the identification information stored in the identification element. 
     Some embodiments include monitoring the container for an indication of an imminent nuclear explosion, and in response to a detection of an imminent nuclear explosion, transmitting a message including information indicative of the identity of the container. 
     Various embodiments may include any of the above described features, alone or in any combination. These and other features will be more fully appreciated with reference to the following detailed description which is to be read in conjunction with the attached drawings. 
     In is to be understood that, as used herein, the term “detecting a beam” and related terms refer to detecting any property of a beam of radiation (e.g. an x-ray beam) including, but not limited to: intensity, fluence, cross section, wavelength, pulse duration, etc. Further, it is to be understood that detecting a beam may include detecting the interruption or blocking of a beam (e.g. when an x-ray beam is blocked by metallic material positioned between the beam source and the detector). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects of this disclosure, the various features thereof, may be more fully understood from the following description, when read together with the accompanying drawings in which: 
         FIG. 1  illustrates a prior art container scanning system; 
         FIG. 2  illustrates a system for scanning and certifying containers; 
         FIGS. 3-6  illustrate potential attacks on a system for scanning and certifying containers; 
         FIG. 7  shows a perspective view of a container and a scanning system; 
         FIG. 8  illustrates a scanning pattern on a container panel; 
         FIG. 9  illustrates a triage and scanning system; 
         FIG. 10  is a block diagram showing a dosimeter installed in a container; 
         FIG. 11  illustrates a scanning system for use with a dosimeter installed in a container; 
         FIG. 12  a perspective view of a dosimeter installed in a container and a scanning system; 
         FIG. 13  shows a perspective view of a container with composite plugs and a scanning system; 
         FIG. 14  shows a perspective view of a container with composite plugs and a scanning system; 
         FIG. 15  is a block diagram of a remotely controlled scanning system and container with composite plug; 
         FIG. 16  shows a top down view of a container with composite plugs and a fabric liner containing intrusion detection grids; 
         FIG. 17  is a schematic diagram illustrating an exemplary structural member including dispersed, interconnected electronic components; 
         FIG. 18  is a schematic diagram illustrating interconnection of multiple structural members of  FIG. 17 ; and 
         FIG. 19  is a block diagram illustrating in more detail an exemplary one of the electronic components of  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION 
     The following discloses a system  10  for scanning shipping containers (e.g. maritime containers) for the presence of a concealed nuclear weapon before the container is loaded onto transport, e.g. a ship bound for the US from a foreign nation. System  10  is an inexpensive automated defense which will allow commerce to flow rapidly. An inexpensive automated defense can be widely deployed, with the result that it may become financially and operationally feasible to scan 100% of containers entering the US. 
       FIG. 1  depicts the current scanning methods, where many containers  12  line up to pass through a very expensive high power x-ray scanner  14 . Numerous on-site operators  16  are required and they must be trusted in order for the system to work. This method is so slow and so expensive that most containers  12  are not scanned, even though 100% scanning of inbound containers will be required a few years from now, according to recent federal legislation. The scanning operation has to be close to loading crane  18 , since there is no procedure except physical control to assure that the container is not breached after scanning and prior to loading. 
     Referring to  FIG. 2 , system  10  is a system for scanning shipping containers  20 . System  10  includes one or more scanning lanes  22 . Remote monitor unit  24  is in communication with scan lane  22  over the internet  26  (or other suitable communication link or network). 
     Container  20  is constructed from multiple panels defining an interior volume. The panels may be entirely or partially constructed from composite material which has relatively high transmissivity to x-ray radiation compared to conventional container panel materials (e.g. steel). 
     Container  20  includes a security element  27  which monitors the container for breach or intrusion. For example, as described in detail below, one or more of the panels of container  10  may be composite panels embedded with a multitude of electrically or optically interconnected sensors which can detect a breach in the panel. 
     Scanner  28  includes beam generator  30  which transmits a directed radiation scan beam  32  (e.g. an x-ray beam) along a path through a composite portion of a sidewall of container  20 , across a portion of the interior volume, and out through a composite portion of the opposing sidewall and onto scan beam detector  34  position the other side of the container. 
     Because scan beam  32  is directed through composite portions of container  10  having relatively high transmissivity, beam generator  30  may have relatively low power (and hence low cost) beam source. As described in detail below, signals from scan beam detector  34  may be analyzed to determine information about the material properties of cargo (not shown) located in the interior volume of container  10 . For example, blockage of the beam might indicate the presence of dense material such as metal. Using the techniques described below, scanner  28  can operate to scan the entire contents of container  10  to determine the presence of a nuclear weapon. 
     Scanner  28  is in communication with remote monitor unit  24 . Signals from scan beam detector  34  and/or analyzed data indicating, e.g., the presence or absence of a nuclear weapon within container  10  may be transmitted to remote monitor unit  24 . Scanner  28  can operate to modulate a message received from the remote monitor unit onto scan beam  32 . 
     Scan beam detector/demodulator located inside container  10  can detect scan beam  32  and demodulate a message modulated onto the beam. In some embodiments, detector/demodulator  36  may also function to modulate additional messages onto scan beam  36  which can be detected and demodulated by scan beam detector  34  after scan beam  32  exits container  20 . In this fashion, a one or two way directed beam communication link may be established with detector/demodulator  36 . 
     Detector/demodulator  36  is in communication with identification element  38  which includes an electronic memory capable of, as described in more detail below, storing information including electronic IDs and other data. Identification element  38  may also include a processor capable of processing the stored data. Identification element  38  also includes a non-directed wave transmitter (e.g. a radio transmitter, RF transmitter, Bluetooth antenna, etc.) which transmits messages based on the stored data. Identification element  38  is also in communication with security element  27 , which, upon detecting a breach of container  10 , may cause identification element  38  to modify or destroy the stored electronic ID and/or other data. 
     Receiver  40 , positioned in or near scanning lane  22 , can receive the non-directed transmissions from identification element  38 . For example, receiver  40  may be a laptop or personal computer. Receiver  40  is in communication with remote monitor unit  24  via the internet  26 . 
     Dosimeter  39  is positioned inside container  10 , and may be in communication with one or more of identification element  38 , security element  27 , and detector/demodulator element  36 . As described in detail below, dosimeter  39  can detect the presence of even lead shielded fissile material located inside container  20 . In some embodiments, if fissile material is detected, dosimeter  39  can produce an alarm which causes cause identification element  38  to modify or destroy the stored electronic ID, certificates, and/or other data. 
     Explosion detector  41  is positioned inside container  20 , and operates to detect the presence of an imminent nuclear explosion (e.g. by detecting x-rays, gamma rays, neutrons, thermal emissions, etc.). Explosion detector  41  can transmit a warning message which includes information indicating the identity of the container. Thus, in the event of a system failure leading to a nuclear explosion, the source of the explosion can be more easily tracked. 
     The following will describe how system  10  will scan container  20  for the presence of a nuclear weapon, and present the container with a certificate certifying that it has been scanned. As described below, such a certificate can be secured so that it can be trusted when presented at a later time and position, e.g., at the loading crane which loads container  10  onto a transport. 
     Container  10  is driven into scanning lane  20  analogous to the lanes in a highway toll booth. Scanner  20  modulates a query message onto scan beam  32  which is detected and demodulated by detector/demodulator element  36 . In response to the demodulated query message, identification element  38  transmits a response message including stored identity data via Bluetooth to receiver  40 , which passes the response message via the Internet to remote monitor unit  24 . 
     Remote monitor unit  24  generates a token (e.g. a random number) and sends it to scanner  28 . Scanner  28  modulates the token over scan beam  32 . Detector/demodulator  36  detects the scan beam, demodulates the token from the beam, and communicates the token to identification element  38 , which sends the token back to receiver  40  via Bluetooth. Receiver  40  sends the token via the Internet back to the remote monitor. 
     After the transmission and receipt of the token described above, remote monitor unit  24  can verify (e.g. using a look up list of electronic IDs installed in various containers at a secure production facility) that the container associated with the electronic ID produced by identification element  38  is in fact container  10  which is physically present in lane  20  in front of scanner  28 . This assurance permits secure remote management of the scan itself. 
     Using the techniques described herein, scanner  28  scans container  20  for the presence of a nuclear weapon. If the container passes the scan, scanner  28  sends a certificate to remote monitor unit  24 , which stores it. This certificate associates the container&#39;s ID with the fact that the container passed the scan. In some embodiments, dosimeter communicates information regarding the presence of fissile material with scanner  28  and receiver  40 , which may be passed on to remote monitor unit  24 . The issuance of the certificate may be based on this information. 
     After leaving scanning lane  20 , when the container is presented for loading by the loading crane, one need only obtain the ID of the container, communicate with the remote monitor, and determine if this container has been issued a certificate certifying that it has passed a scan. 
     For example, a loading crane may pick up container  10 . Through a PC built into the loading crane, remote monitor  24  communicates with identification element  38  in the container to obtain electronic ID information, determines whether the ID is valid and whether a scanning certificate has been issued. If the ID is valid and there is a scanning certificate, the remote monitor instructs the loading crane to load the container on board the ship. In typical applications, this entire procedure takes less than a second. If there is an invalid ID or no certificate, the crane would deposit the container in a secure area for containers that need to be examined by the proper authorities. The process of how the validity of an ID is determined is described in detail below. 
     Identification element  38  stores a public and a private ID. In response to a query (e.g. modulated over a scan beam and demodulated by detector/demodulator element  36 ), identification element  38  sends a public ID to remote monitor unit  24 , e.g. via a Bluetooth receiver linked via the internet to the monitor. Remote monitor unit  24  then generates a question, which it sends to identification element  38  (e.g. via a scan beam). The identification element  38  transmits an answer to the question which is received and returned to remote monitor unit  24 . The question remote monitor unit  24  sends is a randomly generated number (e.g. a 32 bit number). Using a hash algorithm of the type familiar to those in the art, identification element  38  prepares a response hash of this number and the stored hidden ID, and returns this response hash value, the answer, to remote monitor unit  24 . Using the same algorithm, remote monitor unit  24  prepares a verification hash of its copy of the hidden ID associated with the public ID presented by identification element  38 . If the response and verification hashes are identical, the probability that identification element  38  locate in container  10  does not contain the correct hidden ID is near zero. Note that, since the question is generated randomly, identification element  38  is almost certainly never asked the same question twice. If container  10  is asked the same question twice, identification element  38  will realize this, and will alarm. Only an identification element  38  that has the correct hidden ID will answer these randomly generated questions with the answer that is correct for a particular question. 
     Using the presented public ID, remote monitor unit  24  can look up the private ID that the identification element  38  should possess. Using the question, the answer, and the correct private ID stored with the remote monitor, the remote monitor can determine whether identification element  38  actually does possess this ID. Using this type of procedure, remote monitor unit  38  can determine whether identification element  38  possesses a certain ID without ever having to transmit the secret portion of the ID outside identification element  38 . 
     As described above, security element  27  and dosimeter  39  may operate to modify or destroy the hidden ID in response to detection of intrusion/tampering and the presence of fissile material, respectively. Accordingly, the identification process described above can also be used to identify containers subject to tamper or containing hidden fissile material. 
     The above described procedure for testing the secret ID is used both during the scanning of container  20  in scan lane  22  and when the container is presented for loading. 
     Referring again to  FIG. 2 , container  20  should pass a scan and be issued a certificate if (a) no dense metal is detected; (b) the container has a valid ID; and (c) dosimeter  39  does not detected hidden fissile materials 
     About one third of all in-bound US containers will contain dense metal, and so for these containers, condition (a) will not be met. For these containers it is possible to issue a certificate on the basis of conditions (b) and (c). In other words if dosimeter  39  has not detected fissile material and the container has a valid ID, the container should be issued a certificate for loading. 
     There are many reasons why container  20  would not have a valid ID. One reason is that the container had never been issued at ID. Issuance of IDs is discussed below. Another reason that container  20  would not have a valid ID would be detection of some type of an alarm condition. When an alarm condition is detected, identification element  38  destroys part of the ID so that the container cannot thereafter present a valid ID. Alarm condition could include a breach through the sides of a container detected by security element  27 , an attempt to reverse engineer identification element  38 , detection of fissile material by dosimeter  39 ; detection of an air change by dosimeter  39  (described in detail below). 
     The following describes various possible attacks against the system  10 , and how system  10  defeats the threat.  FIG. 3  illustrates a threat presented when a container  20  which has never been scanned is presented for loading at crane  52 . Following the procedures described above, when container  20  arrives at the loading dock crane  52 , remote monitor  24  (not shown), using a scanner located at or near crane  52 , attempts to communicate with the identification element which should be inside. If the remote monitor cannot do this, the container is not loaded. 
     If remote monitor unit  24  can communicate with an identification element in container  20 , remote monitor  24  will check to determine if the ID stored in the identification element is valid. If the ID is valid, remote monitor  24  will verify that a container with this ID has been scanned (e.g. by searching for a certificate associated with the container). In the illustrated threat in this section, the container has not been scanned, there will be no certificate, and container  20  will not be loaded. 
       FIG. 4  illustrates an attack, whereby after container  20  has passed a scan and been issued a certificate, but before being presented for loading at crane  52 , an adversary breaks into container  20  and inserts a nuclear weapon. The defense involves detecting the attack, and upon detection destroying part of the hidden ID in identification element  38 . If the data including the hidden ID is destroyed, identification element  38  will not be able to correctly answer the question posed by remote monitor  24 , and the container will not be loaded. 
     As discussed in detail below, security element  27  can detect a breach through the walls of the container. Security element  27  is connected to identification element  38 . When the identification element  38  is alerted that the container has been breached, it destroys a part of the private ID as described above. When container  20  is later presented for loading at crane  52 , the container will not pass a question and answer interrogation. This will mean that something is wrong and the container should not be loaded. 
     In some embodiments, identification element  38  consists of a circuit embedded into a composite material. This circuit contains numerous electronic elements which store the values which make up the ID. Destroying one of these elements will cause the identification element  38  to fail the question and answer dialogue with remote monitor  24 . 
     When identification element  38  destroys part of the ID by destroying an electronic element, it does not merely electronically erase the information from the element, but chemically or thermally destroys the element so that the element can never be made to reveal its prior contents. An adversary with advanced technology can sometimes recover a number which has been erased using simple electronic methods. A composite material is superior to silicon as a substrate for an electronic circuit, because data destruction functionality is difficult to implement in silicon. 
       FIG. 5  illustrates the threat of spoofing attack. For this attack an adversary produces two containers  20 A and  20 B each including an identification element  38  storing the same ID. Container  20 A is scanned and contains no harmful material. Container  20 B has the nuclear weapon and is not scanned. Container  20 B is then presented to loading crane  52 . Since both containers have the same ID, the loading crane  52  believes container  20 B is container  20 A. An adversary can practice this attack with harmless merchandise. When the adversary is certain that the spoofing operation works properly, the adversary can commit a nuclear weapon to the importation process with low risk that the weapon will be discovered and lost and that an alarm will be sounded. 
     System  10  defends against this threat by assuring that no two containers can have the same ID and that an adversary cannot discover the ID of the container. An ID embedded in a silicon chip can be discovered by a sophisticated adversary using the Focused Ion Beam System (FIBS) which takes a silicon chip apart molecule by molecule. FIBS reverse engineering services are readily available on the market. 
     In some embodiments, identification element  38  represents a defense against FIBS. Identification element  38  may be a circuit embedded not into silicon but into composite material whereby the elements are widely dispersed and continuously check on one another. When attack is sensed, identification element  38  permanently destroys various elements of the ID by burning or chemical methods so that the previous value of the element cannot be recovered, even by a sophisticated adversary. 
     Also, as previously described above, the identification element  38  uses a question and answer procedure whereby the presence of a particular ID can be remotely detected without ever having to send the ID itself over the internet or other long distance public channel. 
       FIG. 6  illustrates an attack where an adversary attempts to fool the scanner so that one container  20 A is scanned whereas another container  20 B provides the ID. System  10  defends against this threat using the closed loop identification techniques described herein to verify that the container in communication with remote monitor  24  is actually located in the appropriate scan lane  22  in front of scanner  28   
     In such techniques, information is exchanged over a directed X-ray or microwave or other wave by modulating and demodulating the information using well-known technology. Of course this exchange of information may be encrypted. A sophisticated adversary could possibly intercept the exchanged information and defeat the protection using a variation of the man-in-the-middle attack, whereby the scanner believes it is communicating with the container, and the container believes it is communicating with the scanner, but in fact both are communicating with an adversary that has been interposed between them. System  10  may employ methods to detect a man-in-the-middle attack known in the art. 
     Attacks involving placing a hidden shielded nuclear weapon in container  20  may be defeated by system  10  by employing a dosimeter of the type described in detail below. 
     There is a possibility an adversary could attempt to discover the ID embedded in identification element  38  by bribing or intimidating employees in the factory where the ID is installed. 
     When the ID is installed in identification element  38  in container  20 , it is generated by remote monitor  24  and transferred over the Internet to the factory for installation into identification element  38 . This is the only occasion when the ID travels over the Internet and when it exposed outside the remote monitor. 
     As described above, after this time, the remote monitor queries identification element  38  to determine if the element has a particular ID, but this procedure does not involving actually communicating the ID outside of identification element  38 . 
     For the initial transfer, the ID is encrypted using secure methods involving asymmetric and symmetric encryption methods. Under this procedure, identification element  38  will generate an asymmetric public/private key pair, send the public key to the remote monitor, which generates a symmetric key and encrypts that key with the public key, and returns the encrypted symmetric key to the identification element  38 , which uses the private key to decrypt the symmetric key. The symmetric key is now used to encrypt the ID elements. 
     Using the above technique, system  10  can protect the ID elements when they are installed at the factory. The factory manufacturing identification element  38  itself would also be physically secure and could be located inside the United States. 
     There is a possibility that an adversary could bribe or intimate a trusted employee working at a remote site (e.g. scan lane  22 ) so as to obtain container IDs. This employee might be so trusted that the employee was given “root” or administrative access, meaning the employee was authorized to perform system maintenance tasks. To avoid this, security techniques may be employed to prevent access to critical data, including for example, limiting the availability of certain sensitive operating system functions and/or deleting, modifying, or destroying the critical data when the use of certain sensitive operating system functions are detected. 
     In various embodiments, system  10  may feature any of the following elements and techniques, alone or in combination. 
     Composite Container Scanner and Triage System 
     Referring to  FIG. 7 , container  100  is constructed from composite panels  102  enclosing an interior volume. Scanner  106  includes directed radiation beam emitter source  108  which produces scan beam  110 . Scan beam  110  is directed along a path which travels through a side panel  102  of container  100  into the interior volume, across a portion of the interior volume, out of opposing side panel  102 , and onto detector  112 . Scanner  106  includes directed x-ray beam emitters  108 . A detector signal from detector  112  is transmitted to a remote control unit (not shown), and analyzed to determine the material properties of cargo (not shown) loaded in the interior volume of container  100 . For example, the detector signals can be analyzed to determine the presence of metals, fissile material, medium density material (e.g. electronic components), etc. In some embodiments detector  110  may be in communication with a local analyzer, such as a personal computer or laptop. 
     In the illustrated embodiment, where container  100  is a rectangular parallelpiped, scan beams  110  and their respective emitters  108  and detectors  112  are along axes parallel to one of the sidewalls of container  100 . In some embodiments, beams  110  and their respective emitters  108  and detectors  112  may be angularly offset with respect to the container sidewall. 
     Because panels  102  are made of composite material having relatively high transmissivity (e.g. in comparison to metal, such as steel), scan beam  110  need not be a high energy beam. Accordingly emitter  108  may be an inexpensive, relatively low power beam emitter. For example, emitter  108  may have sufficient power to penetrate composite panels  102  and low density, non-metal cargo loaded into the interior volume of container  100 , but insufficient power to penetrate dense, bulk metal (e.g. steel, lead, fissile material) etc. In such a case, an interruption of scan beam  110  measured by detector  112  would indicate the presence of dense metal material in the interior volume. 
     In various embodiments, emitter  108  may be low-voltage x-ray source (e.g. a 200 kV or less x-ray source) or a cobalt-60 x-ray source. A scanner including such a source could be manufactured at a cost of about $10,000 or less. In contrast, to generate a scan beam with sufficient energy to penetrate a steel container would require a high voltage x-ray source operating at 3000 kV or more. 
     Container  100  can be moved relative to scanner  108  and detector  112  (e.g. by driving a truck hauling the container past scanner  106 ) to allow scan beam  110  to be directed through additional points on side panel  102  such that additional portions of the interior volume are scanned. Alternatively, scanner  108  and detector  112  may be moved relative to container  100  to scan different portions of the interior volume. For example, referring to  FIG. 8 , a scan could sample data points for scan beams directed through points  150  on side panel  102  located every six inches vertically and horizontally. For example, for a 20 foot by 5 foot panel a total of (40*10)=400 data points might be sampled, with each data point indicating the presence or absence of metal along the scan beam passing through a given point. The results of this scan may be analyzed and compared to a threshold to determine the presence of, for example, a nuclear device. For example, if less than 30 of the 400 data points in the example above showed the presence of metal, it may be determined that the container does not contain a nuclear weapon with a probability of error of 1 part in 1 trillion. The 400 point data sample will be compressible into a computer file size of 40 bytes, allowing easy storage or transmission to, for example, a remote monitoring or control unit. 
     In some embodiments, scanner  106  may contain multiple emitters:  108  which may produce multiple scan beams  110  simultaneously or sequentially. As described in greater detail below, in some embodiments only select portions of one or more of panels  102  of container  100  consist of composites with the remainder being made up of metal (e.g. steel). The composite portions allow scan beam  110  to access the interior volume of the container. 
     As will be discussed in greater detail below, in some embodiments it is possible to place a detector inside a shipping container  100  that could detect a scan beam  110 . With an appropriate detector, messages could be modulated over the scan beam and demodulated by the detector, so that the scanner could communicate with the detector inside the container. Such communication capability could be useful for a remote monitor to communicate (e.g. using wireless, radio, or Bluetooth links) with a sensor or identification elements inside the container and also to communicate with the same container over the scan beam. This would allow remote assurance that the container in front of the scanner was the same container that was in communication with the remote monitor. 
     Approximately 66% of container traffic inbound to the West Coast of the US is volume limited. Of this traffic, half contains no metal (i.e. clothing and shoes), a quarter contains electronic parts and games, and the remainder contains other goods such that a full 20 ft. container weighs less than the maximum weight of 67,200 lbs. A scanner slightly more powerful than the type of scanner discussed above could be built that would penetrate a cargo consisting of light electronic goods but would be blocked by dense metal. A nuclear weapon will contain dense metal, even if not shielded with lead. If shielded with lead, it will be even denser. Consequently, 33% of the inbound West Coast Cargo traffic could be scanned with an inexpensive scanner and declared not to contain metal, provided the cargo were transported in a composite container. On the assumption that if a container does not contain metal, it does not contain a nuclear weapon, 33% of the inbound container traffic to the West Coast can be inexpensively scanned and declared safe. 
     In the following, an exemplary scanning and triage system is disclosed for efficiently scanning multiple at least partially composite containers for the presence of a hidden nuclear device. 
     Referring to  FIG. 9 , system  500  includes one or more low power scanners  502  having a scan beam with insufficient energy to penetrate dense metals or medium density partially metallic material (e.g. electronic components). The system also includes one or more medium power scanners  504  having a scan beam with insufficient energy to penetrate dense metals but sufficient energy to penetrate medium density partially metallic material (e.g. electronic components). The system also includes one or more high power scanners  506  having a scan beam with sufficient energy to penetrate dense metals. 
     Any of scanners  502 ,  504 ,  506  could be coupled with a data collection program on a lap top or remote monitoring unit which analyzes scan data using one or more of the techniques described above to determine information about the content of the containers. 
     Containers  508  that are represented as containing non-metallic low density material such as clothing are directed to low power scanners  502 . Containers  508  which pass this scan (i.e. if no metal is detected in the container) are declared not to contain a nuclear weapon. These containers would not have to be scanned by a more powerful and more expensive scanner. Approximately one third of in-bound container traffic in the U.S. is of this type. This will save money in scanning equipment and delay. 
     Containers  510  that are represented as containing electronic components or other medium density cargo are directed to the medium power scanners  506  suitable for this type of cargo. Containers  510  which pass this scan (i.e. if no metal having a density greater than that typical of medium density cargo is detected) are declared not to contain a nuclear weapon. These containers would not have to be scanned by a more powerful and more expensive scanner. Approximately one third of in-bound container traffic is medium density. This will save money in scanning equipment and dock delay. 
     Containers  512  that are represented as containing high density metallic material are directed to high power scanners  512 . These scanners can scan the containers for nuclear weapons using, for example, high energy x-ray scanning techniques known in the art. Containers  512  which pass this scan (i.e. if no metal having a density greater than that typical of medium density cargo is detected) are declared not to contain a nuclear weapon. 
     In some embodiments, containers  508 ,  510 ,  512 , are secured so that after scanning the container, a breach through any of its six sides will be detected (e.g. using a sensor grid embedded in the composite panels of the containers of the type described in U.S. Patent Publication No. 20070229285 filed Oct. 4, 2007 and entitled “Secure panel with remotely controlled embedded devices”). In such a case, it would be feasible to scan containers at some distance from a dock where the containers are loaded onto a ship bound for the United States. As shown in  FIG. 10 , because containers  508 ,  510 , and  512  can be scanned some distance from the dock, it is feasible to provide numerous scanning lanes for container scanning In typical settings, a great number of such lanes might not be feasible at dockside, where space is limited. Because the need for expensive high power scanners  506  is limited, numerous scanning lanes having low and medium power scanners  502 ,  504  may be provided at a relatively low cost. 
     Further, as described above, analysis of the presence or absence of dense metal is very simple and requires very little data and very little data analysis. Consequently, low and medium power scanners  502 ,  504  (and, in some embodiments, even high power scanners  506 ) may be automated and/or remotely managed. For example, scanners  502 ,  504 , and  506  may be automated using a system analogous to the familiar toll booth automation systems used on highways. Automated scanning reduces or eliminates the need for on-site operators. This will reduce costs and security risks. For example, it will not be necessary to place trust in an on-site operator. This will be a significant advantage in the maritime shipping environment, which is, unfortunately notoriously corrupt in certain venues. 
     Dosimeter 
     Referring to  FIG. 11 , dosimeter  1100  is positioned inside of container  1102 . Container  1102  has exterior walls  1104  defining an interior volume  1106 . Exterior walls  1104  may be metal (e.g. steel), composite, or some combination thereof (e.g. composite panels on a steel frame or steel panels with embedded composite plugs). Interior volume  1106  may be sealed air-tight, such that air does not circulate between the exterior environment and the interior volume. 
     Dosimeter  1100  includes a boron element  1108  capable of measuring the level of radon gas and the neutron level within interior volume  1106 . For example, dosimeter  1100  may be a commercial off-the-shelf radon detector. In some embodiments, such an off-the-shelf detector may be made more sensitive by modifying boron element  1108 , using techniques known in the art. 
     As noted above, detection of radon and neutrons is a good indicator of fissile material. Substances that do not contain fissile material will typically not produce radon and neutrons. 
     When interior volume  1106  of container  1102  is sealed such that the air volume does not circulate, if dosimeter senses less than a threshold number of neutrons and a threshold radon level over a period of time, the probability that the container contains a nuclear weapon approaches zero. The threshold levels and time periods can be easily determined based on measured background neutron and radon levels for a given container type and/or known neutron and radon emission rates for fissile material. 
     In some embodiments, dosimeter  1100  can communicate with devices external to container  1102 . For example, referring to  FIG. 12 , remote controller  1200  is in communication (e.g. over an Internet connection) with scanner  1202  and receiver unit  1204  (e.g. a computer) located in proximity to scanner  1202 . Scanner  1202  includes beam emitter  1206  which directs a radiation beam  1208  (e.g. an x-ray beam) through panel  1104  onto beam detector element  1210 , which is in communication with dosimeter  1100 . Scanner  1202  receives a message from remote control unit  1200  and operates to modulate the message onto beam  1208  emitted. Detector  1210  detects beam  1110  and demodulates the message. In response to the message, dosimeter  1100  outputs information indicating whether fissile material has been detected inside container  1102 . This information is sent to transmitter  1212  which transmits a response message based on the demodulated message and the information output by dosimeter  1100 . The response signal may be sent using a non-directed signal, for example using a radio broadcast or other wireless transmission. As shown, the response message is transmitted over an antenna to a Bluetooth receiver in receiver unit  1204 . Receiver unit  1204  then passes the message to remote control unit  1200 , thereby providing remote monitoring of container  1102  for fissile material. In some embodiments, beam  1208  is directed into interior volume  1106  through a portion of panels  1104  composed of a material having relatively high transmissivity to the radiation beam (e.g. a composite material). This allows emitter  1206  to be a relatively low powered source, e.g. a low voltage (200 kV or less) x-ray source or a cobalt-60 x-ray source. 
     Note that the above described arrangement provides a closed loop so that a remote monitor can be assured of the position of a particular container while communicating with it. The scan beam  1208  is a directed beam, which can be used to assure that the container is located in a particular place, whereas the communication link between transmitter  1212  and receiver  1204 , e.g. using Bluetooth, is a non-directed wave that will only locate a container within the Bluetooth range. 
     This capability of using a communication path consisting of both a directed beam and a non-directed Bluetooth wave would allow a remote monitor to assure that the container with which it was communicating was the container actually being scanned. The ability to assure that a particular container is in front of the scanner is important to avoid various ploys that might be attempted by a clever adversary to avoid the container scanning process. In some embodiments, scanner  1202  and receiver  1204  may be positioned on or in proximity to loading crane  1130 . This allows for a positive identification of container  1102  and a determination that it does not contain a nuclear device immediately prior to loading onto a transport (e.g. a maritime container ship, train, truck, etc.). Of course, identification and determination may additionally or alternatively be made during or after loading and/or before during or after off-loading. 
     Referring to  FIG. 12 , in some embodiments, scanner  1202  emits scan beam  1208  from emitter  1206  which is directed along a path which enters container  1102  through a first panel  1104 A, passes through dosimeter  1100 , exits container  1102  through a second panel  1104 B and is detected by detector  1300 . As described above, a query message (e.g. from a remote control unit) is modulated onto beam  1208 . Beam  1208  is detected by dosimeter  1100  (e.g. either directly using boron element  1108 , or using a separate detector unit), and the message demodulated. In response to the demodulated query, dosimeter  1100  outputs information indicating whether fissile material has been detected inside container  1102 . This information is included in a response message modulated onto beam  1208  by a modulator integral with or in communication with dosimeter  1100 . Detector  1300  detects beam  1208  after it exits container  1100 , and demodulates the response message. Detector  1300  may communicate the response message to a remote controller (not shown), e.g., using an Internet link. 
     Composite Plugs 
     Referring to  FIG. 13 , container  100  is constructed from steel panels  102 ,  102 A,  102 B enclosing an interior volume. Plugs  104  of composite material are embedded in side panels  102 A and  102 B. The composite plugs  104  have relatively high transmissivity to x-ray radiation while steel panels  102 ,  102 A,  102 B have relatively low transmissivity. Accordingly, composite plugs  104  act as x-ray “windows” into the interior volume of container  100 . 
     In the illustrated embodiment, where container  100  is a rectangular parallelpiped, scan beams  110  and their respective emitters  108  and detectors  112  are along axes parallel to one of the sidewalls of container  100 . In some embodiments, beams  110  and their respective emitters  108  and detectors  112  may be angularly offset with respect to the container sidewall. 
     Each plug  104  in side panel  102 A is located directly opposite to a plug  104  in side panel  102 B. Scanner  106  includes directed x-ray beam emitters  108 . The emitters  108  each direct scan beams  110  through one plug  104  in sidewall  102 A, then through the interior volume of container  100 , then through another plug  104  on the opposite sidewall  102 B and on to a detector  112  outside on the other side of the container. The detector signals are transmitted to a remote control unit (not shown), and analyzed to determine the material properties of cargo (not shown) loaded in the interior volume of container  100 . For example, the detector signals can be analyzed to determine the presence of metals, fissile material, medium density material (e.g. electronic components), etc. Because scan beams  110  need not penetrate the steel portions of side panels  102 A,  102 B, emitters  108  may be inexpensive, relatively low power beam emitters. For example, in various embodiments, emitters  108  may be low-voltage x-ray source (e.g. a 200 kV x-ray source) or a cobalt-60 x-ray source. 
     Container  100  can be moved relative to scanner  106  and detectors  112  (e.g. by driving a truck hauling the container past scanner  106 ) to allow scan beams  110  to be directed through additional pairs of plugs to allow other areas of the interior volume to be scanned. Alternatively, scanner  108  and detector  112  may be moved along the length of the container to access different pairs of plugs  104 . In some embodiments, container  10  and scanner  108  and detectors  110  remain stationary during each scan event. For some applications, e.g. for detecting the presence of nuclear weapons, a sufficient quantity of plugs  104  are provided such that that no matter where the weapon was located within the interior, it could be detected by the scan. 
     Composite plugs  104  may be inserted into panels  102 A,  102 B by an operation after the steel panel is stamped, or the operation could be integrated into the stamping operation. 
     In some embodiments, composite plugs  104  have considerable structural strength so that insertion of a plug would not degrade the structural strength of the steel container. 
     In some embodiments, plugs  104  could be retrofitted to an existing steel container  100  at a modest cost so as to overcome the significant cost disadvantage of all—composite containers. 
     Referring to  FIG. 14 , in some embodiments, one or more of the composite plugs  104  located in side panel  102 A contain a lens or scattering element that directs or scatter the incoming beam  110  to form beams  110 A,  110 B, and  110 C, which travel along different paths through the interior volume of container  100 . Each of beams  110 A,  110 B, and  110 C exit the container through a different composite plug  104  in side panel  102 B and is detected by a detector  112 . Thus, a given input beam  110  generates beams  110 A,  110 B, and  110 C which would be detectable by the detector  112  immediately opposite and by detectors  112  the left and right (and/or above and below depending on the type of lens or scattering element). Accordingly, each scanning beam emitted from scanner  108  is able to scan a larger portion of the interior volume of container  100  than in the configuration shown in  FIG. 14 . 
     In some embodiments, several inexpensive beam emitters  108  might be arrayed vertically. Opposite these beams, several detectors  112  would be arrayed both horizontally and vertically. In some embodiments beam sources  108  are pulsed sequentially so that the detected pulse could be measured separately for each beam pulse. In some such embodiments, it might be necessary to stop container  100  and scan it while it was stationary rather than driving the container through a scanner. In some embodiments, indicial markers or position detectors may be used to ensure proper alignment of plugs  104  and scanner  106 . 
     Referring to  FIG. 15 , remote controller  300  is in communication (e.g. over an Internet connection) with scanner  106  and computer  302  located in proximity to scanner  106 . Scanner  106  operates to modulate a message on beam  110  emitted by emitter  108 . Beam  110  is directed through composite plug  104  into the interior volume of container  100 . Detector/demodulator  304  positioned within container  100  detects beam  110  and demodulates the message. Transmitter  306  transmits a response message based on the demodulate message, e.g. over an antenna to a Bluetooth receiver in computer  302 . In some embodiments, other types of transmission can be used including radio, wireless, etc. The above described arrangement provides a round trip loop so that a remote monitor could be assured of the position of a particular container while communicating with it. 
     In some embodiments, a dosimeter  308  is located inside the container. Dosimeter  308  detects the presence of even shielded fissile material. Dosimeter  308  is in communication with detector/demodulator  304  and transmitter  306 . A query message is sent from remote monitor  300  via modulated beam  110  through plug  104  to detector/demodulator  304 . In response to this massage, information indicating the presence or absence of fissile material is sent from dosimeter  308  via transmitter  306  to computer  302  and on to remote monitor  300 . In some such embodiments, a single composite plug could be inserted into the container allowing communication with dosimeter  308  and reducing or eliminating the need to actually scan for metal. 
     Referring to  FIG. 16 , wall fabric liner  400  is installed inside container  100  to enclose substantially all of the interior volume of the container. Wall fabric  400  contains grids (e.g. electrical or optical grids) that produce an alarm if an intrusion is sensed (e.g. in response to a breach in a portion in one of the grids). For example, fabric liner  200  may include dispersed, interconnected electronic components integrally attached to the liner. Each electronic component of the plurality of components may be in communication with a remotely accessible interface and includes a memory for storing a respective sub-division of at least one numeric value. The numeric values can be inserted, altered, or deleted remotely through the remotely accessible interface. Upon detection of an attempted breach of or tamper with fiber liner  400  one or more of the stored sub-divisions are selectively destroyed. Detection of an attempted breach or tamper is remotely observable upon inspection of a previously stored numeric value, subsequently altered in response to detection of a breach of the secured asset. 
     Fabric liner  400  has tabs  402  that stick to the panels  102 ,  102 A,  102 B for easy installation. In some embodiments, the fabric used along the floor of the container has increased durability, since, in typical applications, fork lifts would need to be driven over it. 
     Composite plugs  104  contain connections for insertion of leads  404  from the fabric. These plugs  104  having connections may be installed at or near the corners of a sidewall of container  100 . 
     When the fabric liner  400  is installed and the connections were made with plugs  104 , a scanner could be used to query fabric liner  400  (e.g. using a closed loop modulation/demodulation/response scheme of the type described above) to assure that the system was functioning properly. As described above, fabric liner  400  could contain unique embedded identification information so that by scanning through the plugs  104  to communicate with fabric liner  400 , a remote monitor could assure that the plugs were connecting to one another through the fabric rather than through some wiring device that avoided the fabric liner  400 . Such a configuration allows an inexpensive intrusion detection system to be installed in steel container  100  and permits a remote check-out that the system was providing the required coverage. 
     In some embodiments, fabric liner  400  is manufactured as an integrated electrical unit so that a reduced number of wiring connections would need to be made upon installation. In some embodiments, the fabric liner  400  is capable of being checked out before installation, so that the time spent installing a defective fabric can be avoided. 
     Composite Panels With Intrusion Detection 
       FIG. 17  is a schematic diagram illustrating an exemplary structural member  2100  including a panel  2102 . The structural member  2100  includes multiple electronic components  2104   a,    2104   b,    2104   c,    2104   d,    2104   e  (generally  104 ) distributed throughout the structural member  2100  and attached to the panel  2102 . Each of the electronic components  2104  is coupled to one or more other electronic components  2104  via electrical connections  2106 . Preferably, each of the electronic components  2104  is coupled to more than one of the other electronic components  2104  to preserve networked interconnection of all active electronic components  2104  in the event of one of the electronic component  2104  failing. In some embodiments, the structural member  2100  includes one or more interconnects  2108 , each in communication with a respective one of the electronic components  2104  and adapted for interconnection with similar electronic components  104  of an adjacent structural member ( FIG. 18 ). At least some of the electronic components  104  include a local memory for storing a respective portion, or sub-division of a numeric value as will be described in more detail below. 
       FIG. 18  is a schematic diagram illustrating electrical interconnection of multiple structural members  100  as may be used for a rectangular container asset, such as a shipping container. Illustrated are left and right panels  2100   a,    2100   b,  front, rear, and top panels  2100   c,    2100   d,    2100   e,  and a bottom panel  2114 . In this exemplary embodiment, each of the left, right, front, rear, and top panels  2100   a,    2100   b,    2100   c ,  2100   d,    2100   e  (generally) are similar to the structural member  2100  of  FIG. 17 . One or more jumpers  2110  are provided to join together corresponding electrical interconnects  2108  of adjacent panels  2100 . Thus, a shipping container  2112  configured as shown provides a single dispersed, interconnected network of electronic devices  2104 . 
     As shown in more detail in  FIG. 19 , an exemplary embodiment of one of the electronic components  2104  includes a microprocessor  2120 , a local power source  2122 , and a local memory  2124 . The microprocessor  2120 , powered by the local power source  2122 , includes a communications interface  2128  that can be used for communicating with other electronic components  2104 . The microprocessor  2120  is also in electrical communication with the local memory  2124  that can be used to store one or more numeric values in the form of digital words. As described below, these values can include private and public portions of an ID value  2126   a,    2126   b  (generally  2126 ) and private and public portions of a certificate value  2127   a,    2127   b  (generally  2127 ). ID values  2126  can be preloaded during construction of the structural member  100 ; whereas, the certificate values  2127  can be loaded and re-loaded in the field, as required. 
     In operation, the microprocessor  2120  receives one or more of the numeric values  2126 ,  2127  over the communications interface  2128  and stores (i.e., writes) them in the local memory  2124 . In response to a remote inquiry as to the stored values, the microprocessor  2120  reads the requested values from local memory  2124  and forwards them to the requester via the communications interface  2128 . 
     Some of the electronic components  2104  are configured to receive an input from an external sensor. Sensors can be configured detect a potential breach of or attempted unauthorized access to a secured asset. For example, a sensor may include a photo detector to detect a change in ambient light as might occur during unauthorized opening of a shipping container. Other sensors are configured to detect a physical breach of a container through one or more embedded sensors that might be compromised if a panel of the container was breached. Still other sensors can include thermal sensors, acoustic sensors, shock and vibration sensors, tipping sensors, etc. 
     As shown, at least some of the electronic components  2104  can include a high-energy device  2130  located proximate to the local memory  2124 . The high-energy device  2130  can include an incendiary device or a small explosive charge (i.e., squib). Upon activation, the high-energy device  130  physically destroys at least a significant portion of the local memory  2124  making it impossible for an adversary to reconstruct data that may have been stored therein. The high-energy device  2130  receives an input signal from a tamper sensor  2132 . The tamper sensor  2132  may be the same sensor providing input to the microprocessor  2120 , or a separate sensor  2132  as shown. In some embodiments, two sensors are provided, such that a first sensor used to delete memory in response to a sensed event and a second sensor is used to physically destroy memory in response to a sensed event. 
     In some embodiments, very low power processors  2120  are provided in substrate layers. Very low power, very small processors are currently commercially available, such as the model no. MSP430 series available from Texas Instruments of Dallas, Tex., and the model PIC F10 series, available from Microchip Technology, Inc of Chandler, Ariz., each of which is suitable for being embedded in composite materials in accordance with the invention. Such very low power processors  2120  are designed to run with a power source  2122 , such as a permanent battery, for a period of up to ten years, with present device costs starting at about $0.49, and a current size that is approximately one-tenth the size of a penny (4 mm by 4 mm) The size and the cost per unit will probably decrease significantly in the future. 
     In some embodiments, the structural member is formed of a composite material within which the processors  120  are mounted on a substrate layer. Thus, the composite material replaces standard PVC board on which electronic devices are commonly mounted. To achieve this mounting, the processors are mounted on a substrate fabric, such as a glass fiber, or other type of layer, to allow a resin to flow through the substrate and bond so as to prevent delamination of the resulting composite material. Using very low power processors  2120 , applications can run for up to ten years from a single lithium battery  2122 . 
     One or more or any part thereof of the control, sensing, detection, scanning or other techniques described above can be implemented in computer hardware or software, or a combination of both. The methods can be implemented in computer programs using standard programming techniques following the method and figures described herein. Program code is applied to input data to perform the functions described herein and generate output information. The output information is applied to one or more output devices such as a display monitor. Each program may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the programs can be implemented in assembly or machine language, if desired. In any case, the language can be a compiled or interpreted language. Moreover, the program can run on dedicated integrated circuits preprogrammed for that purpose. 
     Each such computer program is preferably stored on a storage medium or device (e.g., ROM or magnetic diskette) readable by a general or special purpose programmable computer, for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. The computer program can also reside in cache or main memory during program execution. The technique can also be implemented as a computer-readable storage medium, configured with a computer program, where the storage medium so configured causes a computer to operate in a specific and predefined manner to perform the functions described herein. 
     Although in the examples described above container  100  was composed of rectangular panels (e.g. corrugated rectangular panels), it is to be understood that in various embodiments one or more of the panels may be curved and/or have any suitable shape. For example, a tank type container may be made up of a cylindrical panel and two circular end cap panels. Similarly, plugs  104  may be of any suitable shape including, for example square, rectangular, circular, oval, polygonal, etc. The plugs may be arranged in any suitable pattern on any number of the panels. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. The Abstract of the Disclosure is provided with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.