Patent Publication Number: US-2023160956-A1

Title: Method of creating an electronically readable optical fingerprint to protect an electrical interconnect

Description:
BACKGROUND 
     The present disclosure relates to the security of electronic communications and, in particular, to a system and method for determining an integrity of an electronic interconnect between electrical devices. 
     In various electrical system, the security of electronic communication between components of the system is an important issue. An interconnect between two electrical devices provides an electrically conductive pathway by which electrical signals can be sent back and forth. The electrical interconnect is a point of vulnerability, since tapping into the interconnect provides a means of gaining access to information being exchanged along the interconnect. While the interconnect can be monitored electrically, such monitoring comes with a penalty in the performance of the communication and requires additional equipment. Therefore, there is a need to monitor the security of the electrical interconnect that can be integrated into the electrical system without incurring a performance penalty. 
     SUMMARY 
     According to one embodiment of the present disclosure, a method of determining a security of an interconnect is disclosed. Light from a light source is transmitted through an interconnect between a first device and second device, the interconnect including at least one conductive pathway aligned along a direction between the first device and the second device. A first optical signature of the conductive pathway is recorded based on the light received at an optical detector upon passing through the interconnect at a first time. A second optical signature of the conductive pathway is recorded based on the light received at an optical detector upon passing through the interconnect at a second time. The second optical signature is validated against the first optical signature to determine the security of the interconnect. 
     According to another embodiment of the present disclosure, a signal security detection system is disclosed. The system includes an interconnect between a first device and second device, the interconnect having at least one conductive pathway aligned along a direction between the first device and the second device, a light source for transmitting a light through the interconnect, an optical detector for receiving the light passing through the interconnect, and a processor. The processor is configured to record a first optical signature of the interconnect based on the light received at the optical detector at a first time, record a second optical signature of the interconnect based on the light received at the optical detector at a second time, and validate the second optical signature against the first optical signature to determine a security of the interconnect. 
     According to yet another embodiment of the present disclosure, an electrical system is disclosed. The electrical system includes a first device, a second device and an interconnect between the first device and the second device, the interconnect having at least one conductive pathway aligned along a direction between the first device and the second device. The system also includes a light source for transmitting a light through the interconnect, an optical detector for receiving the light passing through the interconnect, and a processor. The processor is configured to record a first optical signature of the interconnect based on the light received at the optical detector at a first time, record a second optical signature of the interconnect based on the light received at the optical detector at a second time, and validate the second optical signature against the first optical signature to determine a security of the interconnect. 
     Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure. For a better understanding of the disclosure with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The subject matter which is regarded as the disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG.  1    shows a schematic diagram of an electrical system, in an illustrative embodiment; 
         FIG.  2    shows a perspective view of a bonding material used to form an interconnect of the electrical system of  FIG.  1   ; 
         FIG.  3    shows an arrangement of the bonding material between a first device and second device of the electrical system; 
         FIG.  4    shows a diagram illustrating an effect of the arrangement the electrically conductive particles in forming an optical signature; 
         FIG.  5    shows a diagram illustrating a method for enhancing an optical signature using a dye; 
         FIG.  6    shows a diagram of the electrical system in an embodiment illustrating an optical path for light traveling through an interconnect; and 
         FIG.  7    shows a diagram for an electrical system in an embodiment illustrating an alternate optical path for light traveling through the interconnect. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a schematic diagram of an electrical system  100 , in an illustrative embodiment. The electrical system  100  includes a first device  102 , a second device  104  and an interconnect  106  between the first device  102  and the second device  104  for secure signal transmission. The interconnect  106  includes conductive pathways therein for transmission of a signal between the first device  102  and the second device  104 . The conductive pathways can be electrically conductive pathways or electrically conductive structures for transmission of an electrical signal between the first device  102  and the second device  104 . A coordinate system  108  is shown to identify an alignment direction of various components of the electrical system. For illustrative purposes, the interconnect  106  extends along the z-axis to connect the first device  102  to the second device  104 . The z-axis is aligned in a direction between the first device  102  and the second device  104 . 
     The electrical system  100  further includes a signal security detection system  110  suitable for determining whether a signal pathway provided by the interconnect  106  is secure or if the interconnect (and, by extension, the signal pathway) has been changed or degraded. The signal security detection system  110  includes a light source  112  that illuminates the interconnect  106  with a light beam and an optical detector  114   a  that receives the light beam after it has interacted with the interconnect  106 . In various embodiments, the optical detector  114   a  includes one or more photodetectors. The light source  112  and the optical detector  114   a  are coupled to a processor  116 . The processor  116  can activate the light source  112  to generate a light beam. The light beam is transmitted through the interconnect  106  to cause a pattern of light to be received at the optical detector  114   a  due to passage of the light beam through the interconnect  106 . The processor  116  records or generates an optical signature from the pattern of light. By obtaining optical signatures at a first time and a second time, the processor  116  can determine the integrity of the interconnect  106 , i.e., whether the interconnect is secure or has been changed, using the methods disclosed herein. 
     In one embodiment, the light source  112  can be an integrated component or embedded component of the first device  102  and the optical detector  114   a  can be an integrated component or an embedded component of the second device  104 . The optical signature is therefore based on an image of light transmitted through the interconnect  106 . Alternatively, the signal security detection system  110  can include an optical detector  114   b  that is an integrated component or embedded component of the first device  102 . The optical signature at the optical detector  114   b  is based on an image of light reflected from the interconnect  106 . The light source  112  can alternatively be located in the second device  104 . However, the placement of the light source  112  and the optical detectors  114   a ,  114   b  in either of the first device  102  and the second device  104  is not meant to be a limitation of the invention. In an alternative embodiment, a light source  112  and optical detector  114   a ,  114   b  can be external to the first device  102  and/or the second device  104 . 
       FIG.  2    shows a perspective view of a bonding material  200  used to form the interconnect  106  of  FIG.  1   . The bonding material  200  includes a matrix material  202 , such as an epoxy material, and a plurality of conductive particles disposed within the matrix material  202 . The matrix material is a transparent or semi-transparent material. In various embodiments, the conductive particles are electrically conductive particles  204 . The electrically conductive particles  204  can be opaque to light within a visible band and/or infrared band of the electromagnetic spectrum. 
       FIG.  3    shows an arrangement of the bonding material between the first device  104  and second device  104  to form the interconnect  106 . The electrically conductive particles  204  are aligned along the z-direction and arranged into electrically conductive columns  320  that are also aligned long the z-direction. The electrically conductive particles  204  within an electrically conductive column  302  establish an electrically conductive pathway  318  between the first device  102  and the second device  104 . An electrically conductive columns  302  is characterized by columnar volume or cylindrical volume within which the electrically conductive particles  204  are randomly arranged or having a non-deterministic arrangement within the cylindrical volume. Each cylindrical volume is spaced apart from its neighboring cylindrical volumes by a region of the epoxy material that has little or no electrically conductive particles  204  therein. The electrically conductive columns  320  can be formed by applying a magnetic field in the z-direction during a bonding process or by orienting conductive fibers in a polymer matrix and slicing the composite more or less perpendicular to the fiber orientation. 
       FIG.  4    shows a diagram  400  illustrating an effect of the arrangement of the electrically conductive particles  204  in forming an optical signature. The optical signature is created by passing a light from the light source  112  through the interconnect to be recorded at the optical detector  114   a . The optical detector  114   a  can include a plurality of photo-sensitive devices  402 . The electrically conductive particles  204  create a random arrangement of shadows  404  at the optical detector  114   a.    
     Due to the unique pattern presented by the random arrangement of electrically conductive particles  204 , it is difficult for an entity to make a change to the interconnect without changing the optical signature noticeably. In addition, since the electrically conductive particles  204  are arranged randomly, it is difficult for an entity that does make a change to the interconnect to be able to reproduce the original arrangement of electrically conductive particles  204 . Thus, any changes to the interconnect can be identified by identifying a change in the optical signature. 
     In order to inspect the optical signal, the light source  112  is activated and a first optical signature is obtained at a first time based on the original arrangement of the electrically conductive particles  204 . At a second time subsequent to the first time, the light source is again activated and a second optical signature is obtained. The processor  116  validates the second optical signature against the first optical signature. If the second optical signature substantially matches or is the same as the first optical signature, the processor  116  outputs a verification signal to indicate that the interconnect is secure and has not been changed. If the second optical signature substantially does not match or is not the same as the first optical signature, the processor  116  outputs a warning signal to indicate that the interconnect is no longer secure or has been changed. 
       FIG.  5    shows a diagram  500  illustrating a method for enhancing an optical signature using a dye  502 . The dye  502  is introduced at one or more selected locations in the bonding material  200  between the light source  112  and the optical detector  114   a  during the bonding process. The dye  502  can affect the wavelength recorded in a section of the optical signature. The optical signatures therefore include the effects of the dye on the light passing through the interconnect. Due to the random placement of the dye  502 , the security provided by the optical signature is increased. 
       FIG.  6    shows a diagram  600  of the electrical system  100  in an embodiment illustrating an optical path  602  for light traveling through an interconnect  106 . The light source  112  is disposed within the first device  102  and the optical detector  114   a  is disposed within the second device  104 . The light from the light source  112  reaches the optical detector  114   a  via an optical path  602  formed primarily through transmission and refraction through the bonding material and reflection from the electrically conductive particles. 
       FIG.  7    shows a diagram  700  for an electrical system  100  in an embodiment illustrating an alternate optical path  702  for light traveling through the interconnect  106 . The light source  112  and the optical detector  114   b  are both disposed within the first device  102 . The light from the light source  112  reaches the optical detector  114   b  via an alternate optical path  702  formed primarily through reflection from the electrically conductive particles. 
     While the present invention discloses conductive pathways that are electrically conductive and which includes conductive particles that are electrically conductive, this is not meant to be a limitation of the invention. In various embodiments, a conductive pathway can be a thermally conductive pathway that includes thermal conductive particles. Addition, a conductive pathway can be both electrically conductive and thermally conductive and include particles that are both electrically conductive and thermally conductive. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one more other features, integers, steps, operations, element components, and/or groups thereof. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for exemplary embodiments with various modifications as are suited to the particular use contemplated. 
     While the exemplary embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.