WO2006115913A2

WO2006115913A2 - Secure transmission cable

Info

Publication number: WO2006115913A2
Application number: PCT/US2006/014601
Authority: WO
Inventors: Thomas Jr. E. Browning; Douglas Sr . E. Piper
Original assignee: Woven Electronics Corporation, A South Carolina Corporation
Priority date: 2005-04-21
Filing date: 2006-04-19
Publication date: 2006-11-02
Also published as: WO2006115913A3

Abstract

The invention consists of a secure data transmission cable for electronically transmitting secure data between remote locations. The data transmission cable comprises a tubular outer protective layer (10), an inner core (12) disposed within the outer protective layer, a data transmission line (14) carried within the inner core for transmitting secure data between the remote locations, and a fiber optic sensor line (16) included in the outer protective layer for detecting unauthorized activity related to the transmission line.

Description

Secure Transmission Cable

Field Of The Invention Cross Reference To Related Application

This application claims the priority and benefit of co-pending Provisional Application, Serial No. 60/673,699, filed on April 21 , 2005, entitled Secure Above Ground Fiber Optic Data Transmission Cable; PCT Application Serial No. PCT/US/2005/40080, filed November 4, 2005, entitled Apparatus and Method for A Computerized Fiber Optic Security System; co-pending U.S. Application Serial No. 11/083,038, filed March 17, 2005, entitled Apparatus and Method for A Computerized Fiber Optic Security System; PCT Application Serial No. PCT/US/2005/40079, filed November 4, 2005, entitled Vehicle Denial Security System; U.S. Provisional Application Serial No. 60/626,197, filed November 9, 2004, entitled Vehicle Denial Security System; PCT Application Serial No. PCT/US/2004/013494, filed May 3, 2004, entitled Fiber Optic Security System for Sensing the Intrusion of Secured Locations; U.S. Application Serial No. 10/429,602, filed May 5, 2003, entitled Fiber Optic Security System for Sensing the Intrusion of Secured Locations; and U.S. Provisional Application No. 60/456,687, filed March 15, 2003, entitled Fiber Optic Security System for Sensing the Intrusion of Secured Locations; all of the above applications being incorporated herein by reference in their entireties. Background Of The Invention

This invention is directed to a secure, above-ground high-speed data transmission cable, and particularly to a cable having a data transmission line and additional surrounding fiber optic lines for security monitoring which may be routed above ground. Data transmission cables are routinely used to transmit highly sensitive data from one computer to another. For example, within a military facility, multiple computers may be linked together over data transmission cables. The users of these computers transmit highly sensitive data relating to military operations and national security over these cables. There exists a need to monitor the cables so as to avoid any interception and theft of the highly sensitive data transmitted on them. For this reason, the cables used in these military facilities are often limited as to their length, as they cannot be monitored over vast lengths.

It is of particular importance to monitor any cables that are above-ground as they are easier to access than buried cables. For a variety of reasons, it is advantageous in certain situations to have data transmission cables above-ground rather than buried. These cables must be monitored to ensure that the data being transmitted over them is not being intercepted by another party. Attempts have been made to monitor fiber optic cables in the past. These attempts have been limited to determining if the cable has been damaged. U.S. Patent Application Publication 2004/0146254 discloses the insertion of an indicator that can be visually seen when the cable has been degraded. While this allows for repair of a damaged cable, it does nothing for securing the underlying fiber optic data transmission cable and data.

Other attempts have been directed toward cables that are buried under water. These cables must be monitored for damage internally as viewing a cable buried under the ocean is extremely difficult. For example, U.S. Patent 4,623,218 discloses the use of electrical leads within the cables that complete a circuit to send a signal indicating that the electrical leads have not been damaged. Once the electrical leads that surround the fiber optic data transmission cable are damaged, the circuit that they complete is broken, and this indicates to an observer that damage has occurred to the cable. This allows cables that have already been damaged to be repaired. Accordingly, an object of the present invention is to provide a secure highspeed data transmission cable protected against accessing of the cable and transmitting data, particularly when installed above ground.

Summary Of The Invention The above objectives are accomplished by providing a secure data transmission cable for electronically transmitting secure data between remote locations in an exposed condition. The data transmission cable comprises a tubular outer protective layer and an inner core disposed within the outer protective layer. A data transmission line is carried within the inner core for transmitting secure data between the remote locations. A fiber optic sensor line is included in the outer protective layer for detecting unauthorized activity relative to the transmission line. The fiber optic data transmission line may comprise a plurality of optical fibers for transmitting data between remote locations. A protective casing surrounds the data transmission line for protecting the fiber optic data transmission line from contacting the outer protective layer. The casing includes an inner and outer casing which move relative to each other to provide flexibility to the inner core. The sensor line may be carried within a hollow tubular strand in the outer protective layer which includes a plurality of reinforcing strands formed with the tubular strand to provide flexibility to the inner core. The tubular strands, which contain sensor lines, and the reinforcing strands may be metallic. A plurality of the tubular strands may be braided in the outer tubular braid wherein each of the tubular strands contains a fiber optic sensor line for detecting unauthorized activity relative to the transmission line.

The objectives are further accomplished by a secure data transmission system for securely transmitting data among remote computers connected by above-ground cables. A data transmission cable is provided for connecting first and second computers. The data transmission cable includes a data transmission line for transmitting data and a fiber optic sensor line for detecting unauthorized activity relative to the cable. A scanning unit is in communication with the fiber optic sensor line for continuously pulsing the sensor line to determine the status of the sensor line. A security computer is provided in communication with the scanning device for determining an initial baseline signal based on the initial pulse. The security computer then compares the baseline signal with a status signal determined based on a later pulse of the sensor line. A fault signal is generated in response to a predetermined charge in the status signal. An audible alarm is included for receiving the fault signal and audibly indicating the occurrence of unauthorized activity is connected to the data transmission cable. The scanning unit may comprise an optical time domain reflectometer (OTDR) for continuously pulsing the sensor line to determine the status of the sensor line. The objectives are further accomplished by a computerized method for the high-speed, secure transmission of data along an accessible transmission line comprises transmitting data along a data transmission line. A protective layer of the cable is provided which surrounds the data transmission line having a fiber optic sensor line extending longitudinally through the protective layer. The sensor line is scanned to determine the status of the line. If a change in a signal transmitted along the sensor line in response to a prescribed attempt to compromise the transmission line is detected, an alarm signal is generated and transmitted to an associated alarm. The alarm is then actuated in response to the attempt to compromise the transmission line. Description Of The Drawings

The construction designed to carry out the invention will hereinafter be described, together with other features thereof. The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein: Figure 1 is a schematic illustration of an embodiment of a secure fiber optic data transmission cable constructed according to the invention for connecting multiple computers and for detecting unauthorized activity relative to the cable.

Figure 2 is a cutaway perspective view illustrating a fiber optic data transmission cable having a data transmission fiber optic line and a plurality of fiber optic security lines according to the invention;

Figure 3 is a sectional view taken along line 3-3 of Figure 2 illustrating a fiber optic data transmission cable according to the invention;

Figure 4 is a schematic view illustrating a fiber optic data transmission cable included in a computerized intrusion detection system according to the invention connecting multiple computers.

Description Of A Preferred Embodiment

Referring now to the drawings, an illustrative embodiment of the invention will be described in more detail.

Figure 1 illustrates the invention in operation. Secure data transmission cable A connects computers 20 and 22, between which data is being transmitted.

Computers 20 and 22 are housed in different buildings. These buildings are an environment where the burying of data transmission cables is not possible. Thus, fiber optic data transmission cable A is disposed above the ground along fence line

30 connecting computers 20 and 22. As the cable is disposed above-ground, it is advantageous for it to have the structure as described above for providing secured data transmission between computers 20 and 22. The cable contains a data transmission line that allows for data to be transmitted between the computers 20 and 22. The cable A also contains a fiber optic sensor line which is connected to a fiber optic scanning unit 26. The fiber optic scanning device in a preferred embodiment is an OTDR (optical time domain reflectometer). The scanning unit 26 is connected to a security computer 24 with an alarm 28. Upon the detection of unauthorized activity on data transmission cable A, alarm 28 will be actuated.

As can best be seen in Figures 2 and 3, a secure data transmission cable, designated generally as A, is illustrated having an outer tubular protective layer 10, and an inner core 12. A fiber optic data transmission line 14 is carried in the inner core extending along the length of the cable for transmitting secured data between remote locations. Data transmission line 14 allows for the transmission of data amongst multiple computers, phones, fax machines, and other data transmission devices. A fiber optic sensor line 16 extends throughout the length of protective layer 10 for protecting the transmission line.

Data transmission line 14 includes a bundle of optical fibers for providing high- speed data transmission. Fiber optic data transmission line 14 is enclosed in an inner casing 17 and an outer casing 19 to protect the bundle of fibers from exposure that could compromise the data being transmitted. Protective casing includes inner casing 17 and outer casing 19 which are used to reinforce the strength of the inner core while allowing for bending of the cable without a loss of strength. Preferably, there are three sensor lines, fiber optic sensor lines 16a, 16b and

16c, included in outer protective layer 10. The security lines may be braided around data transmission line 14 along with braided wires 17 to continuously protect fiber optic data transmission line 12 from unauthorized access along the length of the cable. The fiber optic sensor lines are adapted to carry signals that are used to determine the status of the sensor line. Note that in alternative embodiments, a single fiber optic sensor line may be used to protect a fiber optic data transmission line. In further embodiments, any number of fiber optic sensor lines may be included to protect data transmission line 14. The fiber optic sensor lines are enclosed in single cable jackets 18a, 18b, and 18c, respectively, to ensure exact measurements of the status of the sensor lines.

The detailed description that follows may be presented in terms of steps of methods or in program procedures executed on a computer or network of computers. These procedural descriptions are representations used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. These steps require physical manipulations of physical quantities such as electrical or optical signals capable of being stored, transferred, combined, compared, or otherwise manipulated. A computer readable medium can be included that is designed to perform a specific task or tasks. Actual computer or executable code or computer readable code may not be contained within one file or one storage medium but may span several computers or storage mediums.

These computer readable instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine such that the instructions will execute on a computer or other data processing apparatus to create a means for implementing the functions specified herein.

Scan unit 26 is in communication with security computer system 24. Fault signals are generated to the security computer when a fault condition arises. As used herein, "fault condition" means a condition in which sensor line 16b has been cut or damaged. Scan unit 26 continuously pulses sensor line 16b, in accordance with scanning instructions processed by computer 24. For example, the computer may control the scan unit to pulse the security line every four seconds.

The scan signals are reflected back, and security computer 24 is programmed to compare the scan signals to the baseline signal to determine whether a predetermined signal (attenuation) deviation representing a fault condition has occurred. In the event the fault condition is detected, a fault signal is generated by the computer along with a calculation of the type of fault and location of the fault condition. A set of level data can be included in communication with security computer 24. The set of level data may be in the form of a look-up table containing attenuation levels and corresponding fault information.

When security computer 24 begins operation, a baseline signal must be established. The baseline signal represents the status of the fiber optic cable being monitored at a normal or undisturbed state. Initially, computer 24 processes baseline initialization instructions, which signal scanning unit 26 to pulse security line 16b. The pulse creates a significant rise in signal level, referred to as a reflective launch spike, proceeded by some noise. The normal signal levels start the beginning of the baseline signal. The security computer continues to establish the baseline until a drop to the noise floor occurs indicating the end of the sensor line being scanned. After the drop, further noise occurs. The security computer will then remove a small portion at the beginning of the baseline and a small portion at the end that are merely reflections of the noise launch, and drop. The final baseline signal is then stored for comparison to future attenuations in the sensor line to determine if a fault has occurred.

During the operation, security computer 24 controls scanning unit 26 to continuously pulse sensor line 16b and receive back scan signals representing realtime scans. With each incoming scan signal, the security computer checks to see if any abnormal attenuations are detected. If a fault attenuation is detected, its location is compared to the baseline signal previously acquired. If the attenuation matches a pre-existing attenuation from the baseline, then the security computer will not report a fault. Any sensor line being pulsed will have some bends and attenuations in its baseline signal. A straight cable extending perfectly vertically from scanning unit 26 will be one of the few instances that no attenuations will be found in the baseline. Thus, every attenuation detected by the computer system will not indicate a fault and may simply indicate a pre-existing bend. Further, some attenuations will be slight, indicating a slight movement of the cable that does not indicate a fault. The attenuations that most concern a user of this system will be those that show a breach or significant damage to the sensor line, and hence a fault condition. In this case, an alarm would be actuated. Figures 3 and 4 illustrate the alarm as being a speaker for audibly indicating the occurrence of unauthorized activity on fiber optic cable A. Note that in alternative embodiments, visual or other alarms may be used to indicate unauthorized activity. The location of the attenuation on the signal will correspond to a location on the sensor line where a breach may have occurred. Thus, the security computer 24 would be able to display the location of the breach on an associated map by associating the attenuation in the signal with a breach in the barricade cable. This operation is described more fully in U.S. Patent Application Serial No.: 11/083,038, filed on March 17, 2005, and corresponding PCT Application PCT/US/2005/40079, filed November 4, 2005, herein incorporated by reference.

Thus, it can be seen that an advantageous secure above-ground fiber optic data transmission cable can be had according to the invention using a central fiber optic data transmission line and at least one fiber optic security line. The cable is monitored according to the invention to provide for secure data transmission.

While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.

Claims

What is claimed is:

1. A secure data transmission cable for electronically transmitting secure data between remote locations in an exposed condition comprising: a tubular outer protective layer; an inner core disposed within said outer protective layer; a data transmission line extending longitudinally within said inner core for transmitting secure data between said remote locations; and a fiber optic sensor line extending longitudinally in said outer protective layer for detecting unauthorized activity relative to said transmission line.

2. The cable of claim 1 wherein said fiber optic data transmission line comprises a plurality of optical fibers for transmitting data between remote locations.

3. The cable of claim 1 wherein said fiber optic sensor line comprises a plurality of optical fibers for detecting unauthorized activity relative to said transmission line.

4. The cable of claim 1 further comprising: a protective casing surrounding said data transmission line for protecting said data transmission line and preventing contact with said outer protective layer.

5. The cable of claim 4 wherein said casing includes an inner casing and an outer casing, and said inner and outer casings moving relative to each other to provide flexibility to said inner core.

6. The cable of claim 1 wherein said sensor line is carried within a hollow tubular strand, and said outer protective layer includes a plurality of reinforcing strands formed together with said tubular strand to provide said outer protective layer.

7. The cable of claim 6 wherein said tubular strand and said reinforcing strands are metallic.

8. The cable of claim 6 including a plurality of said tubular strands included in said outer protective layer wherein each of said tubular strands contains a sensor line.

9. The cable of claim 6 wherein said reinforcing strands and said tubular strand containing said sensor line are braided together to form an outer tubular braid providing said outer protective layer.

10. The cable of claim 9 including a plurality of said tubular strands braided in said outer tubular braid wherein each of said tubular stands contains a fiber optic sensor line for detecting unauthorized activity relative to said transmission line.

11. The cable of claim 8 wherein said tubular strands and said reinforcing strands are metallic.

12. A secure data transmission system for securely transmitting data among remote computers connected by an above-ground cable comprising: a data transmission cable connecting first and second computers, said data transmission cable including a data transmission line for transmitting data and a fiber optic sensor line extending generally longitudinally with said data transmission line along the length of said cable for detecting unauthorized activity relative to said cable; a scanning unit in communication with said fiber optic sensor line for continuously pulsing said sensor line to determine the status of said sensor line; and a security computer in communication with said scanning device for determining an initial baseline signal based on said initial pulse, comparing said baseline signal with a status signal determined based on a later pulse of said sensor line, generating a fault signal in response to a predetermined charge in the status signal.

13. The secure data transmission system of claim 12 wherein said data transmission cable comprises: a tubular outer protective layer; an inner core disposed within said outer protective layer; a data transmission line carried within said inner core for transmitting secure data between said remote locations; and a fiber optic sensor line included in said outer protective layer, extending generally longitudinally with said data transmission line along the length of said cable, for detecting unauthorized activity relative to said transmission line.

14. The system of claim 13 further comprising: a protective casing surrounding said data transmission line for protecting said data transmission line and preventing contact with said outer protective layer.

15. The system of claim 14 wherein said casing includes an inner casing and an outer casing, and said inner and outer casings moving relative to each other to provide flexibility to said inner core.

16. The system of claim 13 wherein said sensor line is carried within a hollow tubular strand, and said outer protective layer includes a plurality of reinforcing strands formed together with said tubular strand to provide said outer protective layer.

17. The system of claim 16 including a plurality of said tubular strands included in said outer protective layer wherein each of said tubular strands contains a sensor line.

18. The secure data transmission system of claim 12 further comprising an audible alarm for receiving the fault signal and audibly indicating the occurrence of unauthorized activity.

19. The secure data transmission system of claim 12 wherein said scanning unit comprises an optical time domain reflectometer for continuously pulsing said sensor line to determine the status of said sensor line.

20. A computerized method for the high-speed, secure transmission of data along an accessible transmission line comprising: transmitting data along a data transmission line; providing a protective layer surrounding said data transmission line having a fiber optic sensor line extending longitudinally through said protective layer; scanning said sensor line to determine the status of said line; detecting a change in a signal transmitted along said sensor line in response to a prescribed attempt to compromise said transmission line; and generating an alarm signal in response to said attempt to compromise said transmission line.

21. The method of claim 20 further comprising the step of transmitting the alarm signal to an associated alarm.

22. The method of claim 20 further comprising the step of actuating the alarm to indicate an attempt to compromise the cable.