FIELD OF THE INVENTION

The present invention generally relates to the field of offline authentication of data and the individual represented in machine readable barcode. The invention particularly relates to a method for generating secure barcode for a document and validating the secure barcode and its holder for identifying fake and duplicate documents in offline environment.

BACKGROUND OF THE INVENTION

Document issuers such as identity (ID) card across the world faces increasing challenges every day on protecting their ID card or document against creation of counterfeit ID Card or other documents. One of the serious challenges faced by them may be the circulation of fake or duplicate documents in which the content of the ID card which may include name, photograph, or the like may be changed and counterfeit identity card or document may be created.

In present scenario, documents such as Driving license, vehicle registration certificates, student ID cards, income tax ID cards, mark sheets, or the like may be easily being forged. Creation and circulation of fake documents may possess an alarming message to the society, and a threat to the integrity of both the issuing authority and the document holder. Hence, to add security measures to the document, the document issuer embeds security features such as hologram, micro line printing, embossing, invisible printing, high resolution border, or the likes in the document. But, these security features may be known only to the document issuer and to validate document, the original document may need to be sent to the document issuer for validation.

In some cases, the verifying agency may connect online to fetch the data of the document by sending the document number and fetches the Photograph of the document and other details of the document from the remote server. This may require online access to the remote server over internet to fetch the details. In the remote location where there may not be network connection, the document cannot be validated. Also, this would require the need for the document issuer to expose the data to the external world which poses threat of hacks. None of these security features embedded in the document have the capability to validate electronically and allows the agency to validate the document in offline environment.

Similarly, there may be a need for validating the document holder biometrically to ensure the holder of the document may be the deemed one. Additionally, there may be need for better digital security mechanism for validating the document by any individual interested in validating the authenticity of the data represented in the document. It should be noted that other solutions (for example-smartcard, nfc) may require special hardware for generation as well as validation which may add to the cost of solution implementation and also adds inconvenience to the overall system.

A number of different type of the tools and a method for generating and validating documents using machine readable barcode are available in the prior art. For example, the following patents are provided for their supportive teachings and are all incorporated by reference:

Prior art document, JP2008090842A discloses a system, method, and storage medium of an image and two-dimensional barcode for cross verification of documents. Image data of a document are obtained, processed, and rendered into a barcode. The barcode is assembled into a copy of document image. The barcodes are embedded over the document image, this allows to keep the embedded barcode anywhere in the document. Moreover, the barcode overlaps certain portion, so that it can disclose secret information while maintaining the integrity of the secret information within encoded data of the barcode. However, this prior art document does not appear to discuss an offline validation of the document.

Another prior art document, US20060157559A1 discloses a method for issuing a credential includes scanning in documents (e.g., breeder or ID documents) used to verify the applicant of the credential and creating data records including the image of the documents. As a means to reduce fraud, these data records are linked to the credential and to the issuer location, operator and time and place of issuance. If the document includes machine readable information, the method automatically reads the machine readable information from the document and uses at least part of the machine readable information from the document to pre populate a form used to create a credential, such as an identification document. The method includes applying a transformation to the image of the document that enables protection against fraudulent use. However, this prior art document does not appear to discuss the digitally signing the Meta data and data of document.

Yet another prior art document, CA2594018C discloses that an electronic signatures valid in printed or scanned form. Electronic signatures are embedded in documents such that the electronic signatures are valid even when the document is scanned, printed or stored in paper form. A document includes a barcode embedded into the document. The barcode includes a unique document ID and a unique signature ID identifying the document and the signer of the document. The document also includes language embedded into the document indicating that the signer of the document authorizes paper versions of the document to be accepted as containing a valid electronic signature. However, this prior art document does not appear to discuss the embedment of compressed color/grayscale image in the barcode.

Yet another prior art document, CN101755274B discloses document security assurance method comprising: a step in the document distribution of print dots, as a result of printing in the case of unpredictable unknown, unpredictable changes in the printing by one of the at least one geometric characteristic of the printed dots caused by the point, and prior to said printing step, the distribution is generated so that the point of the point distribution to the step of at least one geometric characteristic between points having varying geometric produced having varying amplitude of said unpredictable variation magnitude . In an embodiment, the step of generating said distribution point in: at least a half-way point of the distribution is not positioned laterally of said point and another four points of distribution, and the distribution of at least part of dot points at least one dimension with the average absolute value of the unpredictable changes of the same order of magnitude. However, this prior art document does not appear to discuss offline validation of the document.

Yet another prior art document, US7168614B2 discloses to a systems and methods for validating the authenticity of a signature on a document by providing a document from an account, the document including an actual signature and a machine-readable identifier, wherein the machine-readable identifier contains a string of data representing the integral characteristics of all valid account signatures and a person-specific confidence threshold. When the document is presented at a point of presentment, the document is scanned into a document-processing machine and the actual signature is compared against all valid account signatures. However, this prior art document does not appear to discuss offline validation of the document.

Yet another prior art document, US20180234659A1 discloses a method of tracking digital images includes inputting data identifying a subject of an image into a camera, acquiring an image with the camera, and storing the image and the inputted data, as Meta data, in an image file when the image is acquired. The method can be implemented using a scanner, a digital camera, and a data processor. The scanner obtains the identifying data and transmits the data to the camera. The camera obtains digital images and embeds the data into digital image files encoding the digital images. The identifying data has a format different from any of the formats processable by the digital camera. The data processor converts the format of the identifying data to one of the plurality of formats processable by the digital camera loads the converted information into the digital camera as Meta data. However, this prior art document includes less information in the barcode.

However, above mentioned references and many other similar references has one or more of the following shortcomings: (a) Less secure data; (b)Less information in the barcode;(c) Offline validation of document is absent (d) Compressed color/grayscale image in the barcode is absent (e) Digitally signing the Meta data and data of document is absent;(f) Disruption of operations, (g) Expensive, and (h) biometric authentication such as live face compared against image from barcode is absent. The present application addresses the above mentioned concerns and shortcomings with regard to providing a method of generating and validating documents using machine readable barcode completely in an offline environment without the need for the issuing authority to expose data to any system.

SUMMARY OF THE INVENTION:

In the view of the foregoing disadvantages inherent in the known types of the method of generating and validating documents using machine readable barcode now present in the prior art, the present invention provides an improved method for generating and validating documents using machine readable barcode. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved method of generating and validating documents using machine readable barcode which has all the advantages of the prior art and none of the disadvantages. An object of the invention is to provide a method of generating and validating documents using machine readable barcode, the method comprising: receiving, by a barcode generating device, a plurality of input data and a Meta data, wherein said Meta data comprises at least one of a bar code issuer identifier, a digital signature algorithm, a plurality of secure barcode, and a barcode sequence number; generating, by the barcode generating device, a digital signature by combining said plurality of input data and said Meta data using an asymmetric Key; generating, by the barcode generating device, a secure barcode comprising said digital signature of at least one of said plurality of input data and said Meta data; printing, by the barcode generating device, said secure barcode in an electronic document; and validating, by a document validating device, said secure barcode in offline mode by comparing said digital signature of said secure barcode with respect to each of said plurality of input data and said Meta data. It should be noted that said plurality of input data and said Meta data may be accessed from a cloud engine. It should be noted that cloud verification and validation of code may be one of the options of validation.

Other ways to validate the secure barcode in offline mode may be using mobile phone, hand held terminals with barcode scanner, stand-alone computer connected with web camera, barcode scanner, or the like.

It is another object of the invention to provide the plurality of input data which comprises at least one of a compressed col or/gray scale photograph, a formatted text data, and/or a fingerprint biometric minutiae.

Yet it is another object of invention to provide the method which further comprises the step of generating said asymmetric key pair using HSM (Hardware Security Module) for carrying said digital signature.

Yet it is another object of invention to provide the method which further comprises the step of validating said digital signature using a public key.

It is another object of the invention that the document validating device comprising a scanner to scan said secure barcode.

It is another object of the invention is that the scanner scans the document containing secure barcode using an optical character recognition (OCR) system and validates the OCR content against data represented in the secure barcode.

It is another object of the invention that the method further comprising displaying said plurality of input data when said secure barcode is validated.

It is another object of the invention is to scan and validate said plurality of input data and said Meta data using standard mobile phone, desktop computer and handheld terminals.

It is another object of the invention is to provide a cloud engine which may access said plurality of input data and said Meta data using a standard internet browser.

It is another object of the invention is that the method further comprising generating a numeric qr-code of said plurality of input data to allow more storage in said secure barcode. It is another object of the invention is to provide a system of generating and validating documents using machine readable barcode, the system comprises: a plurality of processors 102, a computer-readable medium 104, a display 106, a plurality of external devices 110, and a communication network 112.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

Fig.ldepicts a block diagram of an exemplary system for generating and validating documents using machine readable barcode according to one of the embodiments of the present invention.

Fig.2depicts a block diagram for generating digital signature according to one of the embodiments of the present invention.

Fig.3 depicts a method for generating a secure barcode according to one of the embodiments of the present invention.

Fig. 4 depicts an exemplary block diagram for secure barcode verification using face recognition according to one of the embodiments of the present invention.

Fig. 5 depicts a block diagram for binary to numeric data encoding for QR Code generation according to one of the embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

References will now be made in detail to the exemplary embodiment of the present disclosure. Before describing the detailed embodiments that are in accordance with the present disclosure, it should be observed that the embodiments reside primarily in combinations arrangement of the system according to an embodiment herein and as exemplified in FIG 1 - FIG 5.

Fig.l depicts a block diagram of an exemplary system for generating and validating documents using machine readable barcode according to one of the embodiments of the present invention. The system 100 may implement in a barcode generating device, in accordance with some embodiments of the present disclosure. The barcode generating device, may generate and validate documents using machine readable barcode. In particular, the system 100 may include barcode generating device (for example, server, desktop, laptop, notebook, netbook, tablet, smartphone, mobile phone, or any other computing device) that may generate and validate the documents. As will be described in greater detail in conjunction with FIGS. 2 - 5, the barcode generating device may receive a plurality of input data and a Meta data. It should be noted that said Meta data comprises at least one of a bar code issuer identifier, a plurality of secure barcode, and a barcode sequence number. Further, the barcode generating system may generate a digital signature by combining said plurality of input data and said Meta data using an asymmetric key. Moreover, the barcode generating device may generate a secure barcode comprising said digital signature of at least one of said plurality of input data and said Meta data. A document validating device may then validate said secure barcode in offline mode by comparing said digital signature of said secure barcode with respect to each of said plurality of input data and said Meta data using public key corresponding to the private key in the HSM. It should be noted that said plurality of input data and said Meta data is accessed from at least one of a cloud engine or a digital device. Moreover, to generate the secure barcode, it may require at least one of server, desktop, computer, laptop, or the like. Additionally, a hardware Security Module for Asymmetric Key pair generation and signing the Meta Data and Data. The generated secure barcode shall be printed visually using at least one of card printer, barcode printer, ink jet, lasetet printer or the like. As will be appreciated, instead of printing barcode shall also be digitally embedded into PDF document/email/displayed in mobile application. Further, to validate the secure barcode, it may require desktop computer, laptop, mobile phone, hand held terminal, cloud server along with public key to validate the signature and display the data from the secure barcode.

The system 100 may include one or more processors 102, a computer-readable medium (for example, a memory) 104, and a display 106. The computer- readable storage medium 104 may store instructions that, when executed by the one or more processors 102, cause the one or more processors 102 to validate the document, in accordance with aspects of the present disclosure. The computer-readable storage medium 104 may also store various data that may be captured, processed, and/or required by the system 100. The system 100 may interact with a user via a user interface 108 accessible via the display 106. The system 100 may also interact with one or more external devices 110 over a communication network 112 for sending or receiving various data. The external devices 110 may include, but may not be limited to, a remote server, a digital device, or another computing system.

Fig. 2 depicts a block diagram200 for generating a digital signature according to one of the embodiments of the present invention. For ensuring non repudiation of data, the digital signature 206 may be generated by combining Meta data and data. The digital signature 206 may be created using asymmetric cryptography with a private key205. To validate the digital signature206, the system 100 may decode the barcode, and validate the digital signature206 using public key205.

The barcode generating device may receive a message 201which may include a Meta data and a data. The Meta data of the secure barcode contains header information which may include, but may not be limited to secure barcode issuer identifier, digital signature algorithm, single or multiple secure barcode, and barcode sequence number in case of multiple barcode. It should be noted that the secure barcode may be capable of storing at least one of compressed color/grayscale photograph, formatted text data, and fingerprint biometric minutiae format in ISO 19794-2.

Further the barcode generating device may use the hashing algorithm 202 and hash value 203, and further provide to the signature algorithm 204. It should be noted that the information stored inside formatted text data may be compressed using the redefined ASCII character set with custom bitmaps. By way of an example- to represent name of ID card holder or the document holder in uppercase, secure barcode may use bitmap with 5 bits per character with redefined ASCII set with character‘A’ may be represented as ASCII value 0 and‘B’ as 1 and the like.

Moreover, the digital signature may be generated using asymmetric key pair based Digital signature algorithm. The asymmetric key pair may be generated inside FIPS 140 compliant or a certified Hardware security module (HSM). The HSM may allow storage of the asymmetric keys securely in a tamperproof storage device and this hardware device should be capable of carrying out cryptographic digital signature using the private key205 stored inside the HSM.

As will be appreciated, the secure barcode may use the HSM for generating the asymmetric key pair, storing the key pair in its tamperproof internal storage or encrypts the generated asymmetric key pair using the crypto device master key which can then be stored in any external device, allowing backup of master keys securely, and generating the digital signature 206 of the input data inside the cryptographic device using private key 205 of the asymmetric key pair.

It should be noted that the issuer may generate asymmetric key pair inside the HSM and the private key of the key pair may be used to digitally sign the message to be represented in the secure barcode. After generating digital signature, the secure barcode may be generated containing Meta data, actual message and the digital signature. Further, during verification, the verification system uses the public key of the asymmetric key pair of the secure barcode issuer to validate the digital signature read from the secure barcode to ensure non-repudiation of clear message represented in the Secure barcode.

Moreover, to verify the digital signature, both the message (which may include Meta data and data) and the signature may be required. First, a hash value may be created from the data in the same way as it may be done when the signature may be created. This hash value may then verify against the digital signature signed and stored in the barcode, using the public key of the issuer. When the digital signature may match, it may be confirmed that the message may be the one originally signed and that it has not been tampered with.

Fig. 3 depicts a method300for generating a secure barcode according to one of the embodiments of the present invention. The present invention may also allow to generate multiple barcodes to represent large set of data. In this case, more than 1 barcode may be generated and each barcode may have the sequence number embedded in the Meta data allowing the scanning application to read the barcode in any sequence and finally render it on screen. In the case of multiple barcode, digital signature may be generated for the overall data represented in the multiple barcodes. The verifying application may scan the multiple barcodes in any sequence and the application concatenates all the data from multiple barcodes and validate the digital signature using the public key. This is further explained in conjunction with figure 4.

The barcode generating system may receive a plurality of input data which may include a face photo 301, a text data 302, a biometric data 303, or the like. Further, based on the received plurality of input data, the barcode generating system may prepare a message 304. The message 304 may be the combination of the Meta data and the input data. Further, based on a barcode generation algorithm, the barcode generating system may prepare a barcode data 306.

However, for generating the secure barcode, the barcode generating system may include a data preparation module, digital signing module, and a barcode generation module. The data preparation module may takes the input data from external client application over exposed application programming interface (API) or over XML/JSON Service. Moreover, the face photo301, text data 302, along with data formatting information may be compressed using reduced character set encoding. The Image data to be represented in the barcode may be scaled and compressed using standard image compression algorithms which may include, but may not be limited to GIF, PNG, JPG, JPEG2000, HEVC or the like. After preparing the data, Meta data information may be generated for the data.

Further, the digital signaling module may interface with FIPS 140 certified HSM and may generate signature of Meta data and data using private key inside HSM. It should be noted that the asymmetric public-key cryptography algorithm which may include, but may not be limited to El-Gamal, RSA public-key cryptography algorithm, Elliptic curve cryptography, or the like may be used as asymmetric cryptographic algorithm for signing.

Further, the barcode generating module may concatenate Meta data, data and signature and generates barcode. The generated barcode may be any of the standard barcodes which may include, but may not be limited to Quick

Response (QR) code, data matrix, PDF 417, maxi code, and any high capacity barcode. The generated barcode may be in any of the standard image format. By example- GIF, PNG, JPG, BMP, TIFF, or the like. Further, the generated image may be printed in the physical document (eg., Plastic Card, Printed document, etc), embedded in the electronic document (eg, PDF, email, etc.) by the document issuer along with actual document data.

Fig. 4 depicts an exemplary block diagram400 for secure barcode verification using face recognition according to one of the embodiments of the present invention. In the exemplary block diagram 400, the document validating device may validate the data represented in the secure barcode against the data printed or embedded in the ID card, certificate, document, or the like. The validation of the barcode may be achieved by scanning the complete document using a flatbed scanner or camera enabled Mobile Phone. For validating the barcode, the document validating device may include the steps of: identifying the secure barcode in the document at step 401 by scanning the secure barcode at step 402, validating the digital signature at step 403 using the public key 404, and checking whether the digital signature may be valid at step 405.

When the digital signature may be validated by the document validating device at step 405 then the document may be validated based on at least one of the followings: a) Face recognition engine: The face recognition engine may capture a live photo of the document holder at step 407. Moreover, the face recognition system may extract photo from the barcode at step 408. Further, the face recognition system may compare the live photo and the extracted photo from the barcode of the document holder at step 409 based on the face compare service 410. The Face recognition engine may be a deployed part of the verification system to perform face compare offline. It should be noted that the external face compare service 410 may include, but may not be limited to Microsoft Face API, Amazon recognition, Face ++ service, or the like. Further, the face recognition engine may check whether the face compare success or not at step 411. When the face compare may success then the face recognition engine may render data at step 413 by displaying photo and document detail from the barcode. b) Mobile engine: Mobile engine detects the barcode from the streaming image captured using mobile phone camera. The Meta data represented in the barcode may read to check whether it may be the secure barcode. When the read barcode may be the secure barcode then the mobile engine may validate the signature represented in the barcode against the Meta data and data represented in the secure barcode. On successful validation of digital signature, the data may be formatted as per the data formatting information represented in the data and rendered on the mobile screen. c) Handheld terminal engine: Handheld terminal engine may detect the barcode using barcode scanner embedded in the terminal. The Meta data represented in the secure barcode may read to check whether it may be the secure barcode. When the read barcode may be the secure barcode, then the handheld terminal engine may validate the signature represented in the barcode against the Meta data and data represented in the barcode. On successful validation of digital signature, the data may be formatted as per the data formatting information represented in the data and rendered on the handheld terminal screen. d) Desktop computer engine: Desktop Computer engine may detects the secure barcode using at least one of barcode scanner, web camera, flatbed scanner, or the like connected to the computer. The Meta data represented in the barcode may read to check whether it may be the secure barcode. When the read barcode may be secure barcode, then the desktop computer engine validates the signature represented in the secure barcode against the Meta data and data represented in the secure barcode. On successful validation of digital signature, the data may be formatted as per the data formatting information represented in the data and rendered on the desktop computer screen. e) Cloud engine: The Cloud Engine may be accessed using standard Internet browser. In an embodiment, the cloud engine may be connected with web camera or the Barcode scanner. Verifier may open up internet browser and logs on to web portal for validating the certificate or document. The certificate or document containing the secure barcode may be scanned using web camera or barcode scanner. The barcode may be decoded locally and the decoded barcode may be sent to cloud service. When the received barcode data may be the secure Barcode, then the cloud service engine validates the signature represented in the barcode against the Meta data and data represented in the secure barcode. On successful validation of digital signature, the data may be formatted as per the data formatting information represented in the data and sent back to browser for rendering. f) In another embodiment, the cloud engine may be connected with flatbed scanner verifier which may open up internet browser and logs on to web portal for validating the certificate or document. The whole certificate or document containing barcode may be scanned using flatbed scanner. The scanned image may be sent to cloud Service. The cloud service may detects the secure barcode in the scanned document and decodes the barcode. When the decoded barcode data may be the secure barcode, then the cloud service engine validates the signature represented in the barcode against the Meta data and data represented in the secure barcode. On successful validation of digital signature, the data may be formatted as per the data formatting information represented in the data and sent back to browser for rendering. g) Optical character recognition (OCR) engine: In OCR engine, the document may be scanned using flatbed scanner or camera and the OCR engine may extract the text information from the scanned document. The extracted OCR text data may be compared against the data represented in the barcode.

Fig. 5 depicts a block diagram 500for binary to numeric data encoding for QR code generation according to one of the embodiments of the present invention.

At step 501 the barcode generating device may receive data to be encoded to the secure barcode. Further, when the definite result may be empty at step 502 then the barcode generating device may read 14 bits at step 503. Moreover, when the value may be between 8191 10,000 at step 504 then the document validating device may convert read bits to 4 digit numbers and append to result at step 506. But when the value may not fall between 8191 to 10,000 at step 504 then the document validating device may rewind 14 bits in the input data and read only 13 bits at step 505. When end of the input data may be achieved at step 507 the document validating device encode result as numeric data into barcode at step 508. Hence, the present invention may relate to generation of numeric only data from compressed byte array that may be used to generate numeric barcode which may allow storage of more data than storing the binary data as in the Barcode. For example, in QR-Code version 27 (low error correction code), the Qr code specification allows up to 3517 numbers or 1465 bytes of binary data (JIS8 charset). According to JIS8 character set, 0x80 to 0x9F and OxEO to OxFF values cannot be used as they may be reserved and hence will not allow storing of byte data containing any of the above values. Hence, to store these values, the actual data needs to be reencoded to some other format (like base64 and store as Alphanumeric QR code which further reduces the amount of binary data that can be stored in QRcode). Our invention allows storing a minimum of 1428 bytes (up to a maximum of 1538 bytes) of full 8 bit binary data (0x00 to OxFF) in to a Size 27 Numeric QR-code. Roughly that translates storing up to 5% more data and also allowing full 8 bit information and not the reduced charset from JIS8.

In some other embodiments, when the secure barcode issuer issues barcode with wrong data and later reissues with correct data, then the system 100 may blacklist the old code, so that the validation system may not treat the code as valid code. To facilitate this, the system 100 may assign unique serial number for every barcode issued in the system by the issuer. Hence, the serial number of the old code issued for the same document holder may be stored in a black listed list of serial numbers for not allowing the verification application to validate the old code since new code may be issued to the same document holder with updated information.

The meta data of every secure barcode generated by the issuer may also contain unique serial number of the secure barcode. When the issued secure barcode needs to be invalidated, then the serial number of the old secure barcode may be moved to the black listed list. Moreover, the client application validating secure barcode may be configured to go online / update the blacklisted list of serial numbers offline in pre-defmed interval (for example- 15 days / 1 month or as and verification system have access to remote server maintaining blacklisted serial numbers) to keep the blacklisted list of serial numbers up to date.

At the time of validation of the secure barcode, the validation system validates the digital signature by comparing META DATA + DATA. Further, on successful validation, the unique serial number of the code may be checked for its existence in the blacklisted list of serial numbers. Hence, when the serial number exists in the black listed list of serial numbers, the validation system may prompt stating that the code may be black listed.

The benefits and advantages which may be provided by the present invention have been described above with regard to specific embodiments. These benefits and advantages, and any elements or limitations that may cause them to occur or to become more pronounced are not to be construed as critical, required, or essential features of any or all of the embodiments.

While the present invention has been described with reference to particular embodiments, it should be understood that the embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the embodiments described above are possible. It is contemplated that these variations, modifications, additions and improvements fall within the scope of the invention.