System and method for embedding user authentication information in encrypted data

The present invention is directed to a system and method for secure document transmission. The method begins by receiving first and second key portions into a data storage associated with a document processing device. The first key portion suitably includes data representing a user of the document processing device and the second key portion suitably includes data representing a source of at least one electronic document directed for transmission to the document processing device. Next, at least one encrypted electronic document is received into the document processing device, wherein the document includes the second key portion. The received electronic document is then decrypted using the second key portion and the first key portion, which was retrieved from the data storage. Following decryption, a document processing operation is commenced on the decrypted electronic document.

BACKGROUND OF THE INVENTION

This invention is directed to a method and system for secure document transmission. More particularly, this invention is directed to a method and system for registering a user and identifying a document associated with an encrypted electronic document and transmitted to a document processing device over a computer network.

In typical office settings, a computer network generally includes document processing devices, such as printers, copiers, facsimile machines, and scanning devices, which employ little to no inherent data security. Thus, a registered user of the computer network, for example, generally has physical access to each device, thereby enabling the user to access the files being print, faxed or stored on the device. In addition, as document processing requests are transmitted over the computer network, an authorized user has little to no trouble in intercepting such transmissions, either intentionally or accidentally, and viewing the contents thereof. To maintain confidentiality of document data, passwords, usernames, biometrics, and the like, are implemented at the document processing device, thereby preventing even authorized users from viewing the pending processing requests of another user. However, the encryption techniques employed by any such network still leave accessible the document data as it transits the computer network, enabling a user or users to view the data prior to the document processing device receiving and securely storing it. Furthermore, document data transmitted from a user to the document processing device is generally a plain text file, or other non-encrypted data stream, which when intercepted by another user, does not protect the document from unwanted viewing.

The subject invention overcomes the aforementioned problems and provides a method and system for secure document transmission.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a system and method for the secure transmission of electronic document data on a network.

Further in accordance with the present invention, there is provided a system and method for identifying a document from authentication data embedded in a header associated with an encrypted document processing request.

Still further, in accordance with the present invention, there is provided a system and method for identifying a user associated with a document processing request containing an encrypted electronic document.

In accordance with the present invention, there is provided a system for secure document transmission. The system includes receiving means adapted to receive first and second key portions into a data storage associated with a document processing device. The first key portion suitably includes data representing the user of the document processing device and the second key portion suitably includes data representing the source of at least one electronic document directed for transmission to the document processing device. The system further includes receiving means adapted to receive at least one encrypted electronic document into the document processing device where the at least one encrypted electronic document includes the second key portion. The system of the present invention also includes decryption means adapted to decrypt a received electronic document using the second key portion, which was included with the document, and the first key portion, which was retrieved from the data storage. In addition, the system includes commencement means adapted to commence a document processing operation on a decrypted electronic document.

In one embodiment, the first and second key portions are received along with an initial document transmission from a user of the document processing device. Subsequent documents from the same user then need only include the second key portion.

Further in accordance with the present invention, there is provided a method for secure document transmission. The method begins by receiving first and second key portions into a data storage associated with a document processing device. The first key portion suitably includes data representing a user of the document processing device and the second key portion suitably includes data representing a source of at least one electronic document directed for transmission to the document processing device. Next, at least one encrypted electronic document is received into the document processing device, wherein the document includes the second key portion. The received electronic document is then decrypted using the second key portion and the first key portion, which was retrieved from the data storage. Following decryption, a document processing operation is commenced on the decrypted electronic document.

In one embodiment, the first key and the second key portions are received along with an initial document transmission from a user of the document processing device. Each subsequent encrypted document sent from the same user need only include the second key portion.

Still other advantages, aspects and features of the present invention will become readily apparent to those skilled in the art from the following description wherein there is shown and described a preferred embodiment of this invention, simply by way of illustration of one of the best modes best suited for to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modifications in various obvious aspects all without departing from the scope of the invention. Accordingly, the drawing and descriptions will be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

This invention is directed to a system and method for secure transmission of electronic document data on a network. In particular, the present invention is directed to a system and method for identifying a document from authentication data contained in a header associated with an encrypted document processing request. More particularly, the present invention is directed to a system and method for identifying a user associated with a document processing request containing an encrypted electronic document. Preferably, the document processing device is a multifunctional peripheral device, capable of providing scanning, copying, facsimile, printing, document management, document storage, electronic mail, and other functions to a user.

Turning now toFIG. 1, there is shown a system100in accordance with the present invention. As shown inFIG. 1, the system100suitably includes a computer network102. It will be appreciated by those skilled in the art that the computer network102is any computer network, known in the art, which is capable of enabling the communication of data between two or more electronic devices. As the skilled artisan will appreciate, the present invention is capable of incorporation on any such computer network including, for example and without limitation, Ethernet, local area network, wide area network, personal area network, Token Ring, the Internet, intranets, and the like. In the preferred embodiment, the present invention is employed over a corporate, or local area network. The skilled artisan will appreciate that the present invention is equally capable of being employed on a wide area network, a wireless local area network, the Internet, and the like. In one embodiment, the computer network102is suitably equipped with administratively-enabled security protocols, such as unique user identification/password combinations, to control access to the computer network102and any associated electronic devices connected thereto.

The system100further includes a document processing device104, communicatively coupled to the network102via a suitably communications link106. It will be appreciated by those skilled in the art the document processing device104is advantageously represented inFIG. 1as a multifunction peripheral device, suitably adapted to provide a variety of document processing services, such as, for example and without limitation, scanning, copying, facsimile, printing, and the like. Suitable commercially available image generating devices include, but are not limited to, the Toshiba e-Studio Series Controller. In one embodiment, the document processing device104is suitably equipped to receive a plurality of portable storage media, including without limitation, Firewire, MMC, XD, Compact Flash, Memory Stick, and the like. The communications link106is any suitable channel of data communications known in the art including, but not limited to wireless communications, for example and without limitation, Bluetooth, WiMax, 802.11a, 802.11b, 802.11g, 802.11(x), infrared, optical, or any suitable wireless data transmission system, or wired communications known in the art.

As shown inFIG. 1, the system100also includes a storage location108, in data communication with the computer network102via a suitable communications link110. As will be appreciated by those skilled in the art, the storage location108is any mass storage system known in the art capable of receiving, retrieving, storing and managing data. In the preferred embodiment, the central storage location108is any mass data storage device known in the art, for example and without limitation, an integrated magnetic hard drive or other dynamic or static memory storage device, e.g., flash memory. The communications link110is any suitable means of data communication known in the art including, for example and without limitation, wired data communications channels, Bluetooth, WiMax, 802.11a, 802.11b, 802.11g, 802.11(x), infrared, optical, or any suitable wireless data transmission system.

The system100also includes a plurality of client devices, illustrated inFIG. 1as a personal data assistant112, a smart phone116, and a desktop computer120. It will be appreciated by those skilled in the art that the present invention does not require three client devices, but rather is capable of allowing any number of client devices, greater than or less than three, to be used in accordance with the present invention. The personal data assistant112is suitably equipped to communicate with the computer network102via the communications link114. As will be understood by those skilled in the art, the communications link114is representative of a plurality of communications channels which the personal data assistant112is capable of using to exchange data with the network102. Thus, for example and without limitation, the communications link114is any wired or wireless data communications channel known in the art, such as Bluetooth, WiMax, 802.11a, 802.11b, 802.11g, 802.11(x), infrared, optical, and the like. The smart phone116of the system100is suitably adapted to communicate with the computer network102using the communications link118. In accordance with the present invention, the communications link118is advantageously a wireless communications channel, such as, for example and without limitation, a cellular-telephonic connection. It will be understood by those skilled in the art that the smart phone116is any web-enabled telephonic device known in the art and capable of communicating with other personal electronic devices. The desktop computer120is representative of personal computers and laptop computers, which are capable of data communication with the computer network102. The desktop computer120exchanges data with the computer network102via a suitable communications link122. It will be appreciated by those skilled in the art that the type of communications link employed by the computer120is dependent upon the network interface card of the computer120, including wired and wireless compliant cards. The communications link122is any suitable means of data communication known in the art enabling the transmission and receipt of electronic data including, without limitation, Ethernet, Bluetooth, WiMax, 802.11a, 802.11b, 802.11g, 802.11(x), infrared, optical, and the like.

In operation, the client devices112,116, and120are capable of transmitting document processing requests to the document processing device104over the computer network102. For secure transmission, i.e., so other client devices cannot eavesdrop on the transmissions, a client device is equipped, in accordance with the present invention, to securely transmit an encrypted document file containing user and document identification data. For brevity, the personal data assistant112will be used in the following example, however the remaining client devices116and120are equally capable of employing the techniques described below. Thus, when a user of the personal data assistant112requires a document processing operation be performed on a given document, and also requires a greater degree of confidentiality than is generally associated with document processing requests, the user, via a client driver operating on the client device112initiates a secure document processing request.

The client device first generates a random symmetric encryption key, which is used to encrypt the electronic document. Preferably, a random symmetric encryption key is generated each time a secure document processing request is initiated. A symmetric password key is then generated and used to encrypt the random symmetric encryption key. The password key is then divided into two shares. When requesting secure document processing operations for the first time, both shares are sent to the document processing device104, with the first share being stored in the storage location108for future secure document processing operations from the user. The first share is used for registration of the user and subsequent identification of the user, while the second share is sent to identify the document as originating from the particular user. Authentication information, both existing and new, e.g., user identification, domain information, user key information, etc., are suitably embedded into a header. When this request is the first request, both the first share and the second share are added to the authentication information of the header. When this is a subsequent request, only the second share is added to the header, as the first share is accessible to the document processing device from the storage location108. The header is then encrypted using the public key of the document processing device104and added to the encrypted document data. Following encryption, the secure document processing request containing the header and document data is sent the associated document processing device104.

From the server, or document processing device, side, the document processing device104receives a secure document processing request containing an encrypted header and an encrypted electronic document. The document processing device104decrypts the encrypted header using the document processing device104private key to retrieve the second share, or both the second and first shares, if this is the first time the client device112has submitted a secure document processing request. When it is not the first secure document processing request from the client device112, the document processing device104retrieves the first share from the storage location108the first share stored at the storage location108is accessible only when the user enters an associated network domain user-identification/password at the document processing device104. It will be appreciated by those skilled in the art that each user on the network102has a distinct and separate network domain user-identification/password, which is entered at the document processing device104prior to accessing the first share corresponding to that particular user. In an alternate embodiment, the user-identification/password is a local user-identification/password suitably authenticated by an associated authentication server communicatively coupled to the document processing device104. In either event, the first share and the second share are combined to generate the password key, which was used to encrypt the electronic document. The document processing device then decrypts the random symmetric encryption key using the password key. The decrypted random symmetric encryption key is then used to decrypt the electronic document data, whereupon the document processing device104performs the document processing operation associated with the secure document processing request. It will be appreciated by those skilled in the art that further usage of timestamps and the decryption of document encryption keys establish the uniqueness of the document that the user has encrypted. The foregoing system will better be understood by those skilled in the art when viewed in conjunction with the flowcharts described inFIGS. 2 and 3.

Turning now toFIG. 2, there is shown a flowchart200illustrating the client side of the present invention for secure document transmission. Beginning at step202, the client device112receives a secure document processing request command. It will be understood by those skilled in the art that the client device112suitably includes a client driver adapted to facilitate the encryption and formation of the secure document processing request. The skilled artisan will further appreciate that the term “client driver” is used to describe an application running on the client device112which facilitates the operation of the subject method. The client driver then captures existing authentication data from the client device112regarding the user at step204. Preferably, the existing authentication data suitably includes, but is not limited to, a user-ID, domain/realm data, user Kerberos® ticket information, user public key(s), static symmetric key(s), static mobile code(s), shared symmetric key(s), any other trust related information, and the like or any suitable combination thereof. It will be appreciated by those skilled in the art that the foregoing listing is not exhaustive of trust information that the client driver is adapted to capture. Furthermore, the skilled artisan will appreciate that one or more of the items in the aforementioned listing are only captured if applicable to the client device112, the network102, the domain, the server, and/or the associated document processing device104.

Once the designated authentication information has been gathered, flow proceeds to step206, wherein the client driver inserts the captured authentication data into a header associated with the secure document processing request. A determination is then made at step208as whether the current secure document processing request represents the first secure document processing request initiated by the user. When the current secure document processing request is the first such request, flow proceeds to step210, wherein a symmetric password key is generated. It will be appreciated by those skilled in the art that the symmetric password key is a randomly generated encryption key based, in part, on a user password. Other methods, as will be appreciated by the skilled artisan, for generating the symmetric password key are equally capable of being employed by the present invention, without departing from the scope of the instant claims. At step212, a random symmetric encryption key is generated via any means known in the art. The electronic document associated with the secure document processing request is then encrypted at step214using the symmetric encryption key to generate encrypted electronic document data. The symmetric encryption key is then encrypted at step216using the password key. The encrypted symmetric encryption key is then included in the subsequent transmission of the secure document processing request to the document processing device104.

Next, flow proceeds to step218, wherein the symmetric password key is split into a first share (Share1) and a second share (Share2). In the preferred embodiment, the splitting of a key into multiple parts is accomplished using a Blakeley-Shamir secret splitting scheme, however those skilled in the art will appreciate that the present invention is not limited to such a scheme and any other splitting method known in the art that is equally sufficient to divide the password key into Share1and Share2. In accordance with a preferred embodiment of the present invention, the associated client device112advantageously retains a locally stored copy of the password key, Share1, and Share2. At step220, Share1, Share2, and any additional authentication data is added to the header. As will be appreciated by those skilled in the art, the additional authentication data is suitably capable of including, but is not limited to, newly generated authentication information, public keys, private keys, symmetric keys, e.g., the random symmetric encryption key encrypted using the password key, and the like. The skilled artisan will further appreciate that the inclusion of the header enables the document itself to function as a carrier of user authentication information.

Following inclusion of Share1, Share2, and the additional, if any, authentication information, flow proceeds to step232, wherein the header is encrypted using a public encryption key corresponding to the designated document processing device104. The header is then attached to the encrypted electronic document at step234to form the complete secure document processing request. The secure document processing request is then transmitted to the document processing device104at step236for document processing.

Returning to step208, when the requested secure document processing request is not the first such request submitted by the user, e.g., client device112, flow proceeds to step222. At step222, the client device112retrieves the symmetric password key from the corresponding password file. Preferably, the password key is stored in a file on the client device112in accordance with the file management system employed thereon regarding secure data files. Those skilled in the art will appreciate that protection of the password key is suitably accomplished using secure file storage means as are known in the art. A random symmetric encryption key is then generated at step224via any means known in the art. The electronic document data is then encrypted at step226using the generated symmetric encryption key. The random symmetric encryption key is then encrypted at step228using the retrieved password key. It will be appreciated by those skilled in the art that the encrypted random symmetric encryption key is suitably included in the subsequent transmission of the secure document processing request to the document processing device104, preferably embedded in the header affixed thereto. Share2and any additional authentication information are then added to the header at step230. Preferably, the client device112suitably retrieves Share2from an associated local storage for insertion into the header, as set forth at step230. As this request represents a subsequent secure document processing request, it will be appreciated by those skilled in the art that the Share1is already stored on the storage location108.

The header containing the authentication data, Share2, and the additional authentication information is then selectively encrypted using the public key of the document processing device104at step232. It will be understood by those skilled in the art that the client device112suitably gains access to the public key of the document processing device104upon the installation of the client driver, automatically from the document processing device104when it is added to the network102, or alternatively, by a system administrator. The header is then attached to the encrypted document at step234to generate a secure document processing request. The secure document processing request is then sent to the document processing device104at step236for completion of the requested document processing operations.

Referring now toFIG. 3, there is shown a flowchart300illustrating the server side of the present invention for secure document transmission. The flowchart300begins at step302when the document processing device104receives a secure document processing request. The header accompanying the request is then retrieved at step304. Using the document processing device private key, the header is decrypted at step306to retrieve Share2and authentication data. When this is the first secure document processing request received from a particular user, as determined at step308, the header also includes Share1, a copy of which is transmitted at step310to the storage location108for future use by the document processing device104, following a successful authentication of the user at the device104, while temporarily retaining the original for further decryption use. As will be appreciated by those skilled in the art, the document processing device104, upon receipt of authentication information input by an associated user, authenticates the user against a mutually trusted authentication server. Suitable authentication servers include, but are not limited to, Kerberos KDC, Active Directory, internally embedded authentication server, and the like. Share1and Share2are then combined at step314to retrieve the symmetric password key with which the symmetric encryption key used to encrypt the electronic document was encrypted. The password key is then used, at step316, to decrypt the symmetric encryption key with which the electronic document data was encrypted. The document data is then decrypted at step318using the recovered symmetric encryption key. The document processing device104then performs the requested document processing operation on the decrypted electronic document at step320.

Returning to step308, when a determination is made that the received secure document processing request is a subsequent request, i.e., the document processing device104has received at least one previous secure document processing request from the same user (client device112), flow proceeds to step312, where the document processing device104, after a successful authentication of the user at the document processing device104, retrieves Sharel from the storage location108. Following retrieval of Share1from the storage location108, the document processing device104combines Share1with Share2, which was included in the secure document processing request, and generates the symmetric password key at step314. The password key is then used at step316to decrypt the symmetric encryption key that was used to encrypt the electronic document data. At step318, the received encrypted document data is decrypted by the document processing device104using the recovered symmetric encryption key. The document processing device104then outputs the decrypted document in accordance with the secure document processing request at step318. It will be appreciated by those skilled in the art that the subject invention uses Share1for user identification and Share2to identify the document, to which it is affixed, as originating from the user.

The invention extends to computer programs in the form of source code, object code, code intermediate sources and object code (such as in a partially compiled form), or in any other form suitable for use in the implementation of the invention. Computer programs are suitably standalone applications, software components, scripts or plug-ins to other applications. Computer programs embedding the invention are advantageously embodied on a carrier, being any entity or device capable of carrying the computer program: for example, a storage medium such as ROM or RAM, optical recording media such as CD-ROM or magnetic recording media such as floppy discs. The carrier is any transmissible carrier such as an electrical or optical signal conveyed by electrical or optical cable, or by radio or other means. Computer programs are suitably downloaded across the Internet from a server. Computer programs are also capable of being embedded in an integrated circuit. Any and all such embodiments containing code that will cause a computer to perform substantially the invention principles as described, will fall within the scope of the invention.