Decryption device, method for decrypting and method and system for secure data transmission

BACKGROUND

0001The application relates to a decryption device, method for decrypting and method and system for secure data transmission.

0002For secure communication of an electronic document over a communication network, the document can be encrypted in a manner that only an intended receiver of the document can decrypt the document. For encrypting and decrypting documents, several cryptography techniques are known. Techniques of cryptography may generally be divided into two groups: symmetric-key cryptography and public-key cryptography.

0003In symmetric-key cryptography, a sender and receiver of a document share the same key for encryption and decryption of the document. The key must be kept secret to parties other than the sender and the receiver in order to securely communicate the document.

0004In public-key cryptography, a pair of keys including a public key and a private key is employed for encryption and decryption of the document. The public key and its corresponding private key are different, separate keys but are mathematically linked to each other. The public key may be made available to the public but the private key must be kept secret to parties other than the owner of the key pair. Thus, the private key may be also referred to as a secret key. The sender of a document can encrypt the document using the public key of the receiver of the document, send the encrypted document to the receiver and the receiver can decrypt the encrypted document with his/her private key.

0005Either in symmetric-key cryptography or public-key cryptography, encryption of the document may be performed within a secure environment of the sender of the document. Further, the decryption of the document may be performed within a secure environment of the receiver of the document. For example, when electronically communicating via email, the secure environments of the sender and the receiver may be, for example, inside office buildings with secure intranets protected by firewall software from malicious access via the Internet. The document may be transmitted (e.g. sent via email) outside the secure environment of the sender only after encryption of the document. Further, the decryption of the document may be performed only after the encrypted document arrives in the secure environment of the receiver (e.g. received via email). In other words, the document would have encrypted content when the document is outside the secure environments of the sender and the receiver. Thus, even if a third party intercepts the document during transmission, the third party would not be able to understand the content of the document since its content is encrypted.

0006In some circumstances, further improvement of the security in communicating a document may be required.

SUMMARY

0007According to one aspect, a decryption device for decrypting a document encrypted using biometric information of an intended receiver of the document is provided. The decryption device may comprise the following: <ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0000"><ul id="ul0002" list-style="none"><li id="ul0002-0001" num="0008">an imaging device configured to capture an image of at least a portion of the document;</li><li id="ul0002-0002" num="0009">a biometric detection device configured to detect biometric information of a user;</li><li id="ul0002-0003" num="0010">a processor configured to decrypt at least the portion of the document using the captured image and the detected biometric information; and</li><li id="ul0002-0004" num="0011">a display device configured to display at least the portion of the document decrypted by the processor.</li></ul></li></ul>

0012In various aspects stated herein, the “document encrypted using biometric information” may be either an electronic document or a physical document. An electronic document may include digital content that can be displayed, for example, on a screen of an electronic device such as a computer and a mobile device. A physical document may have its content printed on a physical medium such as paper. A physical medium may be any medium on which the content of the document can be printed. In case of an electronic document, the imaging device may capture an image of at least a portion of the encrypted electronic document that is displayed on a display device of an electronic device, e.g. a computer or a mobile device. In case of a physical document, the imaging device may capture an image of at least a portion of a physical medium, e.g. paper, on which encrypted contents of the document is printed. In either case of an electronic document and a physical document, visual representation of the encrypted contents of the document may be presented to a user and the imaging device may capture an image of the visual representation.

0013The decryption device may be implemented on a mobile device. For example, the decryption device in various aspects as stated herein may be a mobile device. In other words, a mobile device may include the features of the decryption device in various aspects as stated herein. In various aspects, examples of a “mobile device” may include, but not be limited to, a mobile phone, a tablet computer, a PDA (personal digital assistant) and a laptop computer.

0014The decryption device may be implemented on a wearable device. For example, the decryption device in various aspects as stated herein may be a wearable device. In other words, a wearable device may include the features of the decryption device in various aspects as stated herein.

0015In one example, the wearable device may be in a form of glasses. In the example in which the wearable device is in a form of glasses, the biometric information used for encrypting the document may be obtained from an image of at least one eye of the intended receiver. Further, in this example, the biometric detection device may be an eye scanner configured to detect biometric information from an image of at least one eye of the user.

0016In various aspects, the biometric detection device may be configured to obtain the biometric information from a fingerprint, an image of an eye, an image of a face, an image of palm veins, a palm print or a voiceprint.

0017According to another aspect, a method for decrypting a document encrypted using biometric information of an intended receiver of the document is provided. The method may comprise the following: <ul id="ul0003" list-style="none"><li id="ul0003-0001" num="0000"><ul id="ul0004" list-style="none"><li id="ul0004-0001" num="0018">capturing, by an imaging device, an image of at least a portion of the document;</li><li id="ul0004-0002" num="0019">detecting, by a biometric detection device, biometric information of a user;</li><li id="ul0004-0003" num="0020">decrypting, by a processor, at least the portion of the document using the captured image and the detected biometric information; and</li><li id="ul0004-0004" num="0021">displaying, by a display device, at least the portion of the document decrypted by the processor.</li></ul></li></ul>

0022Said decrypting at least the portion of the document may include generating a key for decrypting the document from the detected biometric information of the user.

0023In yet another aspect, a method for secure data transmission is provided. The method may comprise the following: <ul id="ul0005" list-style="none"><li id="ul0005-0001" num="0000"><ul id="ul0006" list-style="none"><li id="ul0006-0001" num="0024">encrypting, by a processor, a document using biometric information of an intended receiver;</li><li id="ul0006-0002" num="0025">outputting, by the processor, the encrypted document as an electronic document and/or as a physical document; and</li><li id="ul0006-0003" num="0026">steps of any of the methods in various aspects and examples as stated herein for decrypting a document encrypted using biometric information of an intended receiver of the document.</li></ul></li></ul>

0027Said encrypting a document may include generating a key for encrypting the document from the biometric information of the intended receiver.

0028In one example, said encrypting and said decrypting may be performed according to a symmetric-key cryptography algorithm. In another example, said encrypting and said decrypting may be performed according to a public-key cryptography algorithm.

0029In yet another aspect, a system for secure data transmission is provided. The system may comprise the following: <ul id="ul0007" list-style="none"><li id="ul0007-0001" num="0000"><ul id="ul0008" list-style="none"><li id="ul0008-0001" num="0030">an encryption device including a processor configured to: <ul id="ul0009" list-style="none"><li id="ul0009-0001" num="0031">encrypt a document using biometric information of an intended receiver; and</li><li id="ul0009-0002" num="0032">output the encrypted document as an electronic document and/or as a physical document; and</li></ul></li><li id="ul0008-0002" num="0033">the decryption device in various aspects and examples as stated herein.</li></ul></li></ul>

0034The processor of the encryption device and/or the processor of the decryption device may be further configured to perform operations according to the method in various aspects and examples as stated herein.

0035Further, the decryption device in various aspects and examples as stated herein may perform operation according to any of the method in various aspects and examples as stated herein.

BRIEF DESCRIPTION OF THE DRAWINGS

0036Details of exemplary embodiments are set forth below with reference to the exemplary drawings. Other features will be apparent from the description, the drawings, and from the claims.

0037<figref idref="DRAWINGS">FIG. 1</figref> shows an example of how an encrypted document may be sent from a sender to a receiver.

0038<figref idref="DRAWINGS">FIG. 2</figref> shows an exemplary functional block diagram of an encryption device.

0039<figref idref="DRAWINGS">FIG. 3</figref> shows an exemplary functional block diagram of a decryption device.

0040<figref idref="DRAWINGS">FIG. 4</figref> shows a flowchart of exemplary processing performed by the encryption device.

0041<figref idref="DRAWINGS">FIG. 5</figref> shows a flowchart of exemplary processing performed by the decryption device.

0042<figref idref="DRAWINGS">FIG. 6</figref> shows another exemplary functional block diagram of the decryption device.

0043<figref idref="DRAWINGS">FIG. 7</figref> shows another exemplary functional block diagram of the encryption device.

0044<figref idref="DRAWINGS">FIG. 8</figref> shows a flowchart of other exemplary processing performed by the decryption device.

0045<figref idref="DRAWINGS">FIG. 9</figref> shows a flowchart of other exemplary processing performed by the encryption device.

0046<figref idref="DRAWINGS">FIG. 10</figref> shows an exemplary hardware configuration of a computer that may be used to implement the encryption device and/or the decryption device.

DETAILED DESCRIPTION OF EMBODIMENTS

0047In the following text, a detailed description of examples will be given with reference to the drawings. It should be understood that various modifications to the examples may be made. In particular, one or more elements of one example may be combined and used in other examples to form new examples.

0048An electronic document can be transmitted by means to transfer data using modes like emails via the Internet, SMS (short message service) via mobile phones etc. These modes may be encrypted using a cryptography algorithm according to, for example, symmetric-key cryptography or public-key cryptography. When the receiver receives the encrypted document with his/her electronic device such as a computer or a mobile device, the encrypted document can be decrypted by the electronic device and shown on a display of the electronic device. Once the decrypted document is displayed on the display, not only the intended receiver but also anyone who is nearby might be able to read the document. For example, in a chat-based application on a mobile device, a chat sent by a sender to a receiver could be visible to anyone who gets access to the mobile and the application, even if the application employs a cryptography algorithm for transmitting the chat data. It may be, however, preferably available only to the relevant two people.

0049A confidential document that may need to be encrypted can be not only an electronic document but also a physical document. A physical document may be, for example, a document printed on paper or any other physical medium. A paper document can be easily read by anyone who obtains the document. Thus, measures may have to be taken also for ensuring security of a paper document including confidential information. For example, a checkbook is still used as a primary mode of transferring money in many parts of the world. Also, the fear of a check being intercepted is still valid in many of these places. The data mentioned on the check is ideally supposed to be seen only by a set of few selected people and not everyone.

0050Various examples as will be described below may be applicable to both electronic documents and physical documents.

0051<figref idref="DRAWINGS">FIG. 1</figref> shows an example of how an encrypted document may be sent from a sender to a receiver. An exemplary system shown in <figref idref="DRAWINGS">FIG. 1</figref> may include an encryption device <b>10</b>, a decryption device <b>20</b>, a receiver device <b>30</b>, a network <b>40</b> and a database (DB) <b>50</b>. In the example shown in <figref idref="DRAWINGS">FIG. 1</figref>, a sender S may encrypt a document using the encryption device <b>10</b> and send the encrypted document to a receiver R. The receiver R may decrypt the encrypted document sent by the sender S using the decryption device <b>20</b>.

0052In one example, the sender S may be a company or an organization that issues documents for its customers, members and/or other people who interact with that company or organization. More specific examples of the sender S may include, but not limited to, a financial institution such as a bank, a medical institution such as a hospital, an insurance company and a governmental organization. The receiver R may be an individual or a group of people who may receive confidential documents from the sender S. In another example, the sender S may be an individual person.

0053The encryption device <b>10</b> may be configured to encrypt a document using biometric information of the receiver R of the document. The biometric information may represent human characteristics and traits. For example, the biometric information may be obtained from a fingerprint, an image of an eye, an image of a face, an image of palm veins, a palm print or a voiceprint. Other information representing human characteristics and traits may also be employed for obtaining the biometric information. In various examples as described herein, the biometric information can be used as or used for generating a key for encryption and/or decryption. The biometric information may include features extracted from human characteristics as exemplified above.

0054The database <b>50</b> may store information used for encrypting a document. For example, in case of employing symmetric-key cryptography, the database <b>50</b> may store biometric information of possible receivers of documents issued by the sender S. The encryption device <b>10</b> may be connected to the database <b>50</b> via the network <b>40</b>. The sender S may request the receiver R beforehand to register his/her biometric information to be used in the encryption of a document for the receiver R. For example, the receiver R may personally visit a facility of the sender S and have his/her biometric information detected by a detection device at the facility. The sender S may then store the biometric information of the receiver R in the database <b>50</b>. Alternatively, the receiver R may have his/her biometric information detected by a detection device of his/her own and send the biometric information to the database <b>50</b> via the network <b>40</b>. When storing the biometric information in the database <b>50</b> via the network <b>40</b>, care may have to be taken to establish a secure communication from the detection device of the sender S and/or receiver R to the database <b>50</b>.

0055Further, for example, in case of employing public-key cryptography, the database <b>50</b> may store public keys of possible receivers of documents issued by the sender S. The receiver R may, for instance, let the decryption device <b>20</b> generate his/her key pair, a public key and a private key, using his/her biometric information. The decryption device <b>20</b> may then store the public key in the database <b>50</b>, thereby providing the public key to the sender S.

0056The encryption device <b>10</b> may access the database <b>50</b> to obtain the biometric information or the public key of the receiver R when encrypting a document to be sent to the receiver R.

0057The encryption device <b>10</b> may output the encrypted document as a physical document P and/or an electronic document E. The physical document P may be, for example, a paper document on which the encrypted content of the document is printed. The physical document P may be sent to the receiver R from a sender S of the document by physically transferring the physical document P. Since the physical document P has encrypted content, even if the physical document P is taken or received by someone other than the receiver R, that person cannot understand the content of the physical document P. Accordingly, transferring a physical document P with encrypted content may improve security.

0058The electronic document E may include the encrypted content of the document in a digital format. The electronic document E may be sent, for example, from the sender S using the decryption device <b>10</b> to the receiver device <b>30</b> via the network <b>40</b>. The network <b>40</b> may be a communication network such as a LAN (local area network), a WAN (wide area network) and the Internet. The receiver device <b>30</b> may be a computer configured to receive an electronic document via the network and visually display the received document on a display device. Examples of a computer that can function as the receiver device <b>30</b> may include, but not limited to, a personal computer, a server computer, a laptop computer, a tablet computer, a PDA, a mobile phone, etc. In various examples described herein, the receiver device <b>30</b> may not decrypt the electronic document E received from the sender. The network <b>40</b> may involve at least one of a wireless network and wired network. In another example, the electronic document E may be sent to a device (not shown) of the sender S from the encryption device via the network <b>40</b> or another network and then the device of the sender S may send the electronic document E to the receiver device <b>30</b> via the network <b>40</b>.

0059When the physical document P is sent to the receiver R, the receiver R can view the encrypted content of the document by simply looking at the physical document P itself. When the electronic document E is sent to the receiver device <b>30</b>, the receiver R can view the encrypted content of the document by making the receiver device <b>30</b> display the encrypted content of the document on its screen, for example.

0060In the following, the term “document” may refer to both the physical document P and the electronic document E, unless otherwise noted.

0061In order for the receiver R to understand the content of the encrypted document sent by the sender S, the document must be decrypted. The decryption device <b>20</b> may be configured to decrypt an encrypted document. For example, the decryption device <b>20</b> may capture an image of at least a portion of the document, detect biometric information of the receiver R and decrypt the document using the captured image and the detected biometric information. The decryption device <b>20</b> may then present the decrypted document to the receiver R.

0062An Augmented Reality (AR) device may be used for implementing the decryption device <b>20</b> in various examples described herein. AR is a live, direct or indirect, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated sensory input such as sound, video, graphics or GPS (Global Positioning System) data. AR is related to a more general concept called mediated reality, in which a view of reality is modified (possibly even diminished rather than augmented) by a computer. An AR device may be a mobile device or a wearable device. Examples of a mobile device may include, but not limited to, a mobile phone, tablet computer, PDA (personal digital assistant) or laptop computer. A wearable device may include a computer and may be worn by a person. Examples of a form of a wearable device may include, but not limited to, a watch, bracelet, anklet and glasses. An AR device as an example of the decryption device <b>20</b> may capture an image of at least a portion of the encrypted document as the user views the document with the AR device, decrypt the document using biometric information of the user and provide the user with an augmented view of the decrypted document.

0000Exemplary Embodiments with Symmetric-Key Cryptography

0063In the following, exemplary embodiments involving symmetric-key cryptography is described with reference to <figref idref="DRAWINGS">FIGS. 2 to 5</figref>. In the exemplary embodiments as will be described below, the encryption device <b>10</b>, the decryption device <b>20</b>, the receiver device <b>30</b> and the database <b>50</b> may be connected via the network <b>40</b>, as shown in <figref idref="DRAWINGS">FIG. 1</figref>. In symmetric-key cryptography, the sender and receiver of a document may share a common key for encryption and decryption of the document. In other words, the encryption key and the decryption key may be identical. Examples of symmetric-key cryptography algorithms may include, but not limited to, AES (advanced encryption standard) and DES (data encryption standard).

0064<figref idref="DRAWINGS">FIG. 2</figref> shows an exemplary functional block diagram of the encryption device <b>10</b>. The encryption device <b>10</b> shown in <figref idref="DRAWINGS">FIG. 2</figref> may include a biometric detection device <b>12</b> and a processor <b>14</b>.

0065The biometric detection device <b>12</b> may be configured to detect biometric information of a human. For example, the biometric detection device <b>12</b> may detect biometric information of an intended receiver of an encrypted document. The biometric detection device <b>12</b> may have a configuration suitable for the type of required biometric information. For example, when a fingerprint is used as the biometric information for encryption of the document, the biometric detection device <b>12</b> could be a fingerprint sensor. In another example, when a pattern of an iris or retina is used as the biometric information for encryption, the biometric detection device <b>12</b> could be an eye scanner configured to detect the biometric information from an image of at least one eye of a human. The biometric detection device <b>12</b> may be further configured to store the detected biometric information in the database <b>50</b>. Further, the biometric detection device <b>12</b> may be configured to receive an input indicating the identification information (e.g., name and/or assigned ID number) of the owner of the biometric information and store the identification information in the database <b>50</b> in association with the detected biometric information.

0066The processor <b>14</b> may be configured to perform various processing to encrypt a document. The processor <b>14</b> may include a document receiving module <b>140</b>, an encryption module <b>142</b> and an output module <b>144</b>.

0067The document receiving module <b>140</b> may be configured to receive an electronic document to be encrypted. The document receiving module <b>140</b> may receive the electronic document to be encrypted from an external computer (not shown) connected to the encryption device <b>10</b>, an external database (not shown) which stores the electronic document and/or a storage device (not shown) within the encryption device <b>10</b>.

0068The sender S may provide the processor <b>14</b> with an input indicating which document to encrypt and the intended receiver of the document, using an input device (not shown) of the encryption device <b>10</b>. Alternatively or in addition, an application (not shown) such as a chat-based application may instruct the document receiving module <b>140</b> which document (e.g. chat message) to encrypt and to whom the document should be sent. Such an application may be included within the encryption device <b>10</b> or in a computer external to the encryption device <b>10</b>.

0069The encryption module <b>142</b> may be configured to encrypt the document using the biometric information of an intended receiver of the document received at the document receiving module <b>140</b>. For example, the encryption module <b>142</b> may retrieve the biometric information of the intended receiver from the database <b>50</b> and encrypt the document using the biometric information as an encryption key. The biometric information as an encryption key can be considered as a secret key of a symmetric-key cryptography algorithm. Alternatively, instead of using the biometric information itself as an encryption key, the encryption module <b>142</b> may generate an encryption key from the biometric information. An encryption key generated from the biometric information can also be considered as a secret key of a symmetric-key cryptography algorithm. In this case, the decryption device <b>20</b> may need to be configured to generate a key from biometric information using the same key generation algorithm as the encryption module <b>142</b> of the encryption device <b>10</b>.

0070When the encryption module <b>142</b> accesses the database <b>50</b> to retrieve the biometric information, the sender S using the encryption device <b>10</b> may need to be authenticated using, for example, authentication information of the sender S (e.g., identification information and a password).

0071The output module <b>144</b> may be configured to output the document encrypted by the encryption module <b>142</b> as an electronic document E and/or as a physical document P. When the output module <b>144</b> outputs the encrypted document as an electronic document E, the output module <b>144</b> may, for example, send out the electronic document E via the network <b>40</b> toward the receiver device <b>30</b>. Alternatively or in addition, the output module <b>144</b> may store the electronic document E in a storage device (not shown) within and/or external to the encryption device <b>10</b>. The electronic document E stored in the storage device may subsequently be sent to the receiver device <b>30</b> via the network <b>40</b> from a computer (not shown) of the sender S. When the output module <b>144</b> outputs the encrypted document as a physical document P, the output module <b>144</b> may, for example, instruct a printer <b>60</b> to print out the encrypted document on paper. The printer <b>60</b> may be a printing device configured to print electronic data on paper. The printer <b>60</b> may include, in addition to the printing functionality, functionalities of scanner, copier and/or facsimile machine. The physical document P printed by the printer <b>60</b> may physically be transferred to the receiver R. In the above example where the electronic document E is stored in the storage device (not shown), the electronic document E may later be printed out as a physical document P (with encrypted content) and this physical document P may be transferred to the receiver R.

0072Further, although the exemplary encryption device <b>10</b> shown in <figref idref="DRAWINGS">FIG. 2</figref> includes the biometric detection device <b>12</b>, in other examples, the biometric detection device <b>12</b> may be provided external to the encryption device <b>10</b>.

0073<figref idref="DRAWINGS">FIG. 3</figref> shows an exemplary functional block diagram of the decryption device <b>20</b>. The decryption device shown in <figref idref="DRAWINGS">FIG. 3</figref> may include an imaging device <b>22</b>, a biometric detection device <b>24</b>, a processor <b>26</b> and a display device <b>28</b>.

0074The imaging device <b>22</b> may be configured to capture an image of at least a portion of the document encrypted by the encryption device <b>10</b>. For example, in case the receiver R has received the physical document P with encrypted content, the imaging device <b>22</b> may capture an image of at least a portion of the physical document P. Further, for example, in case the receiver R has received the electronic document E with encrypted content at the receiver device <b>30</b>, the imaging device <b>22</b> may capture an image of at least a portion of the electronic document E displayed on a display or screen of the receiver device <b>30</b>.

0075The biometric detection device <b>24</b> may be configured to detect biometric information of a human. For example, the biometric detection device <b>24</b> may detect biometric information of a user of the detection device <b>20</b>. The biometric detection device <b>24</b> may have the same configuration as the biometric detection device <b>12</b> of the encryption device as described above with reference to <figref idref="DRAWINGS">FIG. 2</figref>.

0076The processor <b>26</b> may be configured to perform various processing to decrypt a document encrypted by the encryption device <b>10</b>. The processor <b>26</b> may include a decryption module <b>260</b> and a display module <b>262</b>.

0077The decryption module <b>260</b> may be configured to decrypt at least the portion of the document using the image captured by the imaging device <b>22</b> and the biometric information detected by the biometric detection device <b>24</b>. The decryption module <b>260</b> may be configured to decrypt the portion of the document using a decryption algorithm corresponding to the encryption algorithm used by the encryption module <b>142</b> of the encryption device <b>10</b> for encrypting the document. For example, in case the encryption module <b>142</b> uses the biometric information itself as a secret key of a symmetric-key cryptography algorithm, the decryption module <b>260</b> may also use the biometric information itself as a decryption key. Further, for example, in case the encryption module <b>142</b> generates a secret key of a symmetric-key cryptography algorithm from the biometric information, the decryption module <b>260</b> may need to be configured to generate a decryption key from the biometric information using the same key generation algorithm as the encryption module <b>142</b>.

0078In any examples of the decryption module <b>260</b> as described above, if the user who has provided the biometric information is the intended receiver R of the document, the decryption key would be the same as the encryption key and, thus, the decryption would be successful. On the other hand, if the user who has provided the biometric information is not the intended receiver R of the document, the decryption key would be different from the encryption key and, thus, the decryption would be unsuccessful.

0079The display module <b>262</b> may be configured to instruct the display device to display at least the portion of the document decrypted by the decryption module <b>260</b>.

0080The display device <b>28</b> may be configure to display, in response to the instruction from the display module <b>262</b>, at least the portion of the document decrypted by the decryption module <b>260</b>. The display device <b>28</b> may be a device to present visual representation of data, for example, liquid crystal display.

0081<figref idref="DRAWINGS">FIG. 4</figref> shows a flowchart of exemplary processing performed by the encryption device <b>10</b> when encrypting a document. The exemplary processing shown in <figref idref="DRAWINGS">FIG. 4</figref> may be started, for example, in response to an instruction to encrypt a document, input by the sender S via an input device (not shown). Such an instruction may include which document to encrypt and identification information of an intended receiver of the document. Alternatively or in addition, the encryption device <b>10</b> may start the exemplary processing shown in <figref idref="DRAWINGS">FIG. 4</figref> when an application within the encryption device <b>10</b> or an application in a computer connected to the encryption device <b>10</b> instructs the processor <b>14</b> of the encryption device <b>10</b> to encrypt a document. The instruction from an application may also include which document to encrypt and identification information of an intended receiver of the document.

0082The exemplary processing shown in <figref idref="DRAWINGS">FIG. 4</figref> starts at step S<b>10</b>. In step S<b>10</b>, the processor <b>14</b> obtains biometric information of an intended receiver of the document. For example, the processor <b>14</b> may obtain the biometric information of the intended receiver from the database <b>50</b> storing biometric information of possible receivers of documents issued by the sender S. When the processor <b>14</b> receives identification information of the intended receiver, the processor <b>14</b> may retrieve the biometric information from the database <b>50</b> using the received identification information. Alternatively, the processor <b>14</b> may obtain the biometric information of the intended receiver from the biometric detection device <b>12</b>. As stated above, the biometric information may include features extracted from a fingerprint, an image of an eye, an image of a face, an image of palm veins, a palm print or a voiceprint. After step S<b>10</b>, the processing proceeds to step S<b>12</b>.

0083In step S<b>12</b>, the document receiving module <b>140</b> of the processor <b>14</b> receives a document to be encrypted. In one example, the document receiving module <b>140</b> may receive an electronic document from a storage device (not shown) within the encryption device <b>10</b>. In another example, the document receiving module <b>140</b> may receive an electronic document from an external computer (not shown). In yet another example, the document receiving module <b>140</b> may receive an electronic document from an external database (not shown) which stores the electronic document. After step S<b>12</b>, the processing proceeds to step S<b>14</b>.

0084In step S<b>14</b>, the encryption module <b>142</b> of the processor <b>14</b> encrypts the document received in step S<b>12</b>, using the biometric information of the intended receiver. For example, the encryption module <b>142</b> may generate an encryption key from the biometric information obtained in step S<b>10</b> and encrypt the document with the generated encryption key. Alternatively, the encryption module <b>142</b> may use the biometric information obtained in step S<b>10</b> as the encryption key. After step S<b>14</b>, the processing proceeds to step S<b>16</b>.

0085In step S<b>16</b>, the output module <b>144</b> of the processor <b>14</b> outputs the document encrypted in step S<b>14</b>. For example, the output module <b>144</b> may output the encrypted document as an electronic document E. The output module <b>144</b> may send out the electronic document E to the receiver device <b>30</b> and/or store the electronic document E in a storage device (not shown) accessible from the processor <b>14</b>. Alternatively or in addition, the output module <b>144</b> may output the encrypted document as a physical document P. For instance, the output module <b>144</b> may instruct the printer <b>60</b> to print the encrypted document on paper. Further, in case the decryption device <b>20</b> is implemented using an AR device, in step S<b>16</b>, the output module <b>144</b> may include in the output document a marker to be detected by the AR device. The marker can be a trigger for the AR device to know what content and when to display the content. For instance, the AR device functioning as the decryption device <b>20</b> can start processing for decrypting the encrypted document when the AR device detects the marker. The marker may be any unique design such as a logo, text, barcode or QR code. The processing ends after step S<b>16</b>.

0086It should be noted that the exemplary processing shown in <figref idref="DRAWINGS">FIG. 4</figref> is merely one example of the processing performed by the encryption device <b>10</b>. In other examples, processing different from that of <figref idref="DRAWINGS">FIG. 4</figref> may be performed by the encryption device <b>10</b>. For example, step S<b>10</b> of <figref idref="DRAWINGS">FIG. 4</figref> may be performed after step S<b>12</b>. Alternatively, steps S<b>10</b> and S<b>12</b> may be performed simultaneously in parallel. Further, for example, in case the biometric information of the intended receiver is detected by the biometric detection device at step S<b>10</b> of <figref idref="DRAWINGS">FIG. 4</figref>, the processor <b>14</b> may perform a processing step of storing the detected biometric information in the database <b>50</b>, in addition to the processing steps shown in <figref idref="DRAWINGS">FIG. 4</figref>.

0087Further, in the exemplary processing shown in <figref idref="DRAWINGS">FIG. 4</figref>, the processor <b>14</b> of the encryption device <b>10</b> obtains the biometric information of the intended receiver of the document in step S<b>10</b> and the encryption module <b>142</b> of the processor <b>14</b> encrypts the document using the obtained biometric information in step S<b>14</b>. In another example, the encryption module <b>142</b> may obtain from the database <b>50</b> an encryption key generated from the biometric information of the intended receiver of the document in step S<b>10</b>, instead of obtaining the biometric information itself. In this example, the encryption module <b>142</b> may generate the encryption key and store the encryption key in the database <b>50</b> when the intended receiver R lets his/her biometric information detected by the biometric detection device <b>12</b>, before a document to be encrypted is instructed to the processor <b>14</b>. Further, in a variation of this example, the generation and storing of the encryption key may be performed by a device other than the encryption device <b>10</b>. This other device may be configured to obtain biometric information either from a biometric detection device or the database <b>50</b>, generate an encryption key from the obtained biometric information and store the generated key in the database <b>50</b>. The encryption module <b>142</b> of the processor <b>14</b> in the encryption device <b>10</b> may retrieve the encryption key from the database <b>50</b> when encrypting a document.

0088<figref idref="DRAWINGS">FIG. 5</figref> shows a flowchart of exemplary processing performed by the decryption device <b>20</b>. The exemplary processing shown in <figref idref="DRAWINGS">FIG. 5</figref> may be started, for example, when the decryption device <b>20</b> detects the marker for an AR device included in the document with encrypted content. For instance, the imaging device <b>22</b> may capture an image of the marker in the document, the processor <b>26</b> may detect the image as the marker and then the processor <b>26</b> may start the processing shown in <figref idref="DRAWINGS">FIG. 5</figref>. Alternatively or in addition, the exemplary processing shown in <figref idref="DRAWINGS">FIG. 5</figref> may be started when the user of the decryption device <b>20</b> provides an input instructing to decrypt a document, using an input device (not shown).

0089The exemplary processing shown in <figref idref="DRAWINGS">FIG. 5</figref> starts at step S<b>20</b>. In step S<b>20</b>, the imaging device <b>22</b> captures an image of at least a portion of the encrypted document. The encrypted content of the document may be visually presented on a display of the receiver device <b>30</b> in case the receiver device <b>30</b> has received an electronic document E with encrypted content. In case the receiver R has received a physical document P, the encrypted content may be visually presented on a physical medium, e.g. paper. After step S<b>20</b>, the processing proceeds to step S<b>22</b>.

0090In step S<b>22</b>, the biometric detection device <b>24</b> detects biometric information of a user. For example, the biometric detection device <b>24</b> may detect the same type of biometric information as the type used for encrypting the document. As stated above, the biometric information may include features extracted from a fingerprint, an image of an eye, an image of a face, an image of palm veins, a palm print or a voiceprint. For facilitating the detection, the processor <b>26</b> may instruct the display device <b>28</b> to display a message requesting the user to provide the required type of biometric information. For example, if a fingerprint is required, the message may request the user to put his/her finger on a fingerprint reader (as an example of the biometric detection device <b>24</b>). Further, for example, if an image of an eye is required for iris or retina scan, the message may request the user to let the eye scanner (as an example of the biometric detection device <b>24</b>) scan his/her eye(s). After step S<b>22</b>, the processing proceeds to step S<b>24</b>.

0091In step S<b>24</b>, the decryption module <b>260</b> of the processor <b>26</b> decrypts at least the portion of the document using the image captured in step S<b>20</b> and the biometric information detected in step S<b>22</b>. The decryption algorithm used in step S<b>24</b> may correspond to the encryption algorithm used by the encryption device <b>10</b> for encrypting the document. For example, in case the biometric information itself is used as the encryption key of a symmetric-key algorithm, the decryption module <b>260</b> may use the detected biometric information itself as the decryption key in step S<b>24</b>. Further, for example, in case the encryption key of a symmetric-key algorithm is generated from the biometric information, the decryption module <b>260</b> may generate the decryption key in step S<b>24</b> from the detected biometric information. After step S<b>24</b>, the processing proceeds to step S<b>26</b>.

0092In step S<b>26</b>, the decryption module <b>260</b> determines whether the decryption has been successful. If the user who has provided the biometric information is the intended receiver R of the document, the decryption would be successful. If the decryption has been successful (yes in step S<b>26</b>), the processing proceeds to step S<b>28</b>. In step S<b>28</b>, the display module <b>262</b> of the processor <b>26</b> displays the decrypted document on the display device <b>28</b>. For example, the display module <b>262</b> may provide the display device <b>28</b> with the decrypted content of the document and instruct the display device <b>28</b> to display the decrypted content. The processing ends after step S<b>28</b>.

0093If the decryption module <b>260</b> determines that the decryption has been unsuccessful (no in step S<b>26</b>), the processing proceeds to step S<b>30</b>. In step S<b>30</b>, the display module <b>262</b> displays an error message on the display device <b>28</b>. For example, the display module <b>262</b> may instruct the display device <b>28</b> to display a predetermined error message. The processing ends after step S<b>30</b>.

0094It should be noted that the exemplary processing shown in <figref idref="DRAWINGS">FIG. 5</figref> is merely one example of the processing performed by the decryption device <b>20</b>. For example, the decryption device <b>20</b> may end the processing shown in <figref idref="DRAWINGS">FIG. 5</figref> without performing step S<b>30</b>. In case no error message is displayed when the decryption is unsuccessful, the display may, for example, display the image captured in step S<b>20</b> including encrypted content of the document. Further, although step S<b>20</b> is performed before S<b>22</b> in <figref idref="DRAWINGS">FIG. 5</figref>, in another example, step S<b>22</b> may be performed before step S<b>20</b>. In yet another example, steps S<b>20</b> and S<b>22</b> may be performed simultaneously in parallel.

0000Exemplary Embodiments with Public-Key Cryptography

0095In the following, exemplary embodiments involving public-key cryptography is described with reference to <figref idref="DRAWINGS">FIGS. 6 to 9</figref>. In the exemplary embodiments as will be described below, the encryption device <b>10</b>, the decryption device <b>20</b>, the receiver device <b>30</b> and the database <b>50</b> may be connected via the network <b>40</b>, as shown in <figref idref="DRAWINGS">FIG. 1</figref>. In public-key cryptography, the receiver R may generate a key pair including a public key and a private key. The sender S may use the public key of the receiver R for encrypting the document and the receiver R may use the private key for decrypting the document. Examples of public-key cryptography algorithms may include, but not limited to, Diffie-Hellman key exchange and RSA algorithm.

0096<figref idref="DRAWINGS">FIG. 6</figref> shows an exemplary functional block diagram of the encryption device <b>20</b><i>a </i>in the exemplary embodiments involving public-key cryptography. In <figref idref="DRAWINGS">FIG. 6</figref>, components of the decryption device <b>20</b><i>a </i>identical to those of the decryption device <b>20</b> shown in <figref idref="DRAWINGS">FIG. 3</figref> are indicated by identical reference numerals and detailed explanations thereon will not be made here.

0097The decryption device <b>20</b><i>a </i>comprises an imaging device <b>22</b>, a biometric detection device <b>24</b> and a display device <b>28</b>. Each of these devices may have the same configurations as the corresponding device as described above with reference to <figref idref="DRAWINGS">FIG. 3</figref>. The decryption device <b>20</b><i>a </i>further comprises a processor <b>26</b><i>a. </i>

0098The processor <b>26</b><i>a </i>may be configured to perform various processing to decrypt an encrypted document as the processor <b>26</b> as described above with reference to <figref idref="DRAWINGS">FIG. 3</figref>. The processor <b>26</b><i>a </i>shown in <figref idref="DRAWINGS">FIG. 6</figref> may be further configured to perform various processing for generating a key pair for public-key cryptography. The processor <b>26</b><i>a </i>may include a key pair generation module <b>264</b> and a public key registration module <b>266</b>, in addition to a decryption module <b>260</b> and a display module <b>262</b> that are also included in the processor <b>26</b> shown in <figref idref="DRAWINGS">FIG. 3</figref>.

0099The key pair generation module <b>264</b> may be configured to generate a key pair for a public-key cryptography algorithm, using the biometric information detected by the biometric detection device <b>24</b>. For example, the key pair generation module <b>264</b> may receive the biometric information of the receiver from the biometric detection device <b>24</b> and generate a public key and a corresponding private key using the biometric information. In one example, the biometric information itself may be used as the private key and the public key corresponding to the private key may be generated. In another example, the private key may be generated directly from the biometric information and the public key corresponding to the private key may be generated.

0100The public key registration module <b>266</b> may be configured to store the public key generated by the key pair generation module <b>264</b> in the database <b>50</b>. For example, the public key registration module <b>266</b> may access the database <b>50</b> via the network <b>40</b> (not shown in <figref idref="DRAWINGS">FIG. 6</figref>) and store the public key in the database <b>50</b>. The public key may be stored in the database <b>50</b> in association with identification information of the receiver R.

0101In one example, the processor <b>26</b><i>a </i>may delete the detected biometric information and the private key from a storage device (not shown) of the decryption device <b>20</b><i>a. </i>

0102<figref idref="DRAWINGS">FIG. 7</figref> shows an exemplary functional block diagram of an encryption device <b>10</b><i>a </i>in the exemplary embodiments involving public-key cryptography. In <figref idref="DRAWINGS">FIG. 7</figref>, components of the encryption device <b>10</b><i>a </i>identical to those of the encryption device <b>10</b> shown in <figref idref="DRAWINGS">FIG. 2</figref> are indicated by identical reference numerals and detailed explanations thereon will not be made here.

0103The encryption device <b>10</b><i>a </i>shown in <figref idref="DRAWINGS">FIG. 7</figref> does not need to comprise the biometric detection device <b>12</b> included in the encryption device <b>10</b> shown in <figref idref="DRAWINGS">FIG. 2</figref>. The encryption device <b>10</b><i>a </i>comprises a processor <b>14</b><i>a</i>. The processor <b>14</b><i>a </i>may be configured to perform various processing to encrypt a document. The processor <b>14</b> may include a document receiving module <b>140</b>, an encryption module <b>142</b><i>a </i>and an output module <b>144</b>.

0104The document receiving module <b>140</b> and the output module <b>144</b> shown in <figref idref="DRAWINGS">FIG. 7</figref> may have the same configurations as those shown in <figref idref="DRAWINGS">FIG. 2</figref>.

0105The encryption module <b>142</b><i>a </i>may be configured to encrypt a document received by the document receiving module <b>140</b> using the public key of the intended receiver R of the document. For example, the encryption module <b>142</b><i>a </i>may retrieve the public key of the intended receiver R from the database <b>50</b> and encrypt the document using the retrieved public key.

0106<figref idref="DRAWINGS">FIG. 8</figref> shows a flowchart of exemplary processing performed by the decryption device <b>20</b><i>a </i>when generating a key pair for public-key cryptography. The exemplary processing shown in <figref idref="DRAWINGS">FIG. 8</figref> may be started, for example, in response to an instruction to generate a key pair, input by a user, e.g. the receiver R, via an input device (not shown).

0107The exemplary processing shown in <figref idref="DRAWINGS">FIG. 8</figref> starts at step S<b>40</b>. In step S<b>40</b>, the biometric detection device <b>24</b> detects biometric information of a user of the decryption device <b>20</b>. The user may be the receiver R who can receive documents issued by the sender S. The detection of the biometric information in step S<b>40</b> may be performed in a same manner as step S<b>22</b> of <figref idref="DRAWINGS">FIG. 5</figref> as described above. After step S<b>40</b>, the processing proceeds to step S<b>42</b>.

0108In step S<b>42</b>, the key pair generation module <b>264</b> of the processor <b>26</b><i>a </i>may generate a key pair, a public key and a private key, using the biometric information detected in step S<b>40</b>. For example, the key pair generation module <b>264</b> may use the biometric information itself as the private key and generate the public key corresponding to the private key. Alternatively, the key pair generation module <b>264</b> may generate the private key directly from the biometric information and then generate the public key corresponding to the private key. After step S<b>42</b>, the processing proceeds to step S<b>44</b>.

0109In step S<b>44</b>, the public key registration module <b>266</b> stores, in the database <b>50</b>, the public key generated in step S<b>42</b>. For example, the public key registration module <b>266</b> may access the database <b>50</b> via the network <b>40</b> and store the public key in the database <b>50</b> in association with the identification information of the user. The processing ends after step S<b>44</b>.

0110<figref idref="DRAWINGS">FIG. 9</figref> shows an exemplary flowchart of processing performed by the encryption device <b>10</b><i>a</i>. The exemplary flowchart shown in <figref idref="DRAWINGS">FIG. 9</figref> is the same as the exemplary flowchart shown in <figref idref="DRAWINGS">FIG. 4</figref> with respect to the encryption device <b>10</b>, except for steps S<b>11</b> and S<b>13</b>. The situations in which the exemplary processing shown in <figref idref="DRAWINGS">FIG. 9</figref> may be started can be the same as the exemplary situations as described above with respect to the start of the processing shown in <figref idref="DRAWINGS">FIG. 4</figref>. For example, the exemplary processing shown in <figref idref="DRAWINGS">FIG. 9</figref> may be started in response to an instruction by the sender S or by an application to encrypt a document.

0111The exemplary processing shown in <figref idref="DRAWINGS">FIG. 9</figref> starts at step S<b>11</b>. In step S<b>11</b>, the encryption module <b>142</b><i>a </i>of the processor <b>14</b><i>a </i>obtains the public key of an intended receiver of the document. For example, the encryption module <b>142</b><i>a </i>may retrieve the public key of the intended receiver from the database <b>50</b>. After step S<b>11</b>, the processing proceeds to step S<b>12</b>.

0112In step S<b>12</b>, the document receiving module <b>140</b> of the processor <b>14</b><i>a </i>receives a document to be encrypted. The processing of step S<b>12</b> of <figref idref="DRAWINGS">FIG. 9</figref> may be performed in the same manner as step S<b>12</b> as described above with reference to <figref idref="DRAWINGS">FIG. 4</figref>. After step S<b>12</b>, the processing proceeds to step S<b>13</b>.

0113In step S<b>13</b>, the encryption module <b>142</b><i>a </i>encrypts the document received in step S<b>12</b> using the public key obtained in step S<b>11</b>. After step S<b>13</b>, the processing proceeds to step S<b>16</b>.

0114In step S<b>16</b>, the output module <b>144</b> of the processor <b>14</b><i>a </i>outputs the document encrypted in step S<b>13</b>. The processing of step S<b>16</b> of <figref idref="DRAWINGS">FIG. 9</figref> may be performed in the same manner as step S<b>16</b> as described above with reference to <figref idref="DRAWINGS">FIG. 4</figref>. For example, the output module <b>144</b> may output the encrypted document as an electronic document E and/or as a paper document P. In case the decryption device <b>20</b> is implemented using an AR device, the output module <b>144</b> may include, in step S<b>16</b>, the public key in the output document as a marker to be detected by the AR device. As stated above with respect to step S<b>16</b> of <figref idref="DRAWINGS">FIG. 4</figref>, the marker can be a trigger for the decryption processing by the AR device functioning as the decryption device <b>20</b>. The processing ends after step S<b>16</b>.

0115In other examples of processing shown in <figref idref="DRAWINGS">FIG. 9</figref>, steps S<b>11</b> and S<b>12</b> may be performed simultaneously in parallel or step S<b>12</b> may be performed before step S<b>11</b>.

0116In the exemplary embodiments involving public-key cryptography, the decryption device <b>20</b><i>a </i>may perform processing according to an exemplary flowchart shown in <figref idref="DRAWINGS">FIG. 5</figref> when decrypting the encrypted document. The difference of the processing in the exemplary embodiments involving public-key cryptography from the processing as described above with reference to <figref idref="DRAWINGS">FIG. 5</figref> may be that, the decryption in step S<b>24</b> can be made using the private key of the receiver R. The private key can be generated from the biometric information detected in step S<b>22</b>. Alternatively, the biometric information itself can be used as the private key.

Variations

0117It should be appreciated by those skilled in the art that the embodiments and their variations as described above with reference to <figref idref="DRAWINGS">FIGS. 1 to 9</figref> are merely exemplary and other embodiments and variations may exist.

0118For example, the generation of a key pair for public-key cryptography performed by the processor <b>26</b><i>a </i>of the decryption device <b>20</b><i>a </i>shown in <figref idref="DRAWINGS">FIG. 6</figref> may be performed by a computer other than the decryption device <b>20</b><i>a</i>. In one example, the receiver device <b>30</b> may include a processor having the key pair generation module <b>264</b> and the public key registration module <b>266</b> as described with reference to <figref idref="DRAWINGS">FIG. 6</figref> and perform the generation of the key pair and store the public key in the database <b>50</b>.

0119Further, for instance, in the exemplary embodiments with public-key cryptography described above with reference to <figref idref="DRAWINGS">FIGS. 6 to 9</figref>, the document itself may be encrypted using the public key of the receiver R and decrypted using the private key of the receiver R. In another example, the document can be encrypted by a secret key other than the key pair of the receiver R. In this example, not the document but the secret key which has been used for encrypting the document may be encrypted by the public key of the receiver R. In this example, the encrypted document output by encryption device <b>10</b><i>a </i>may include the encrypted content of the document and the encrypted secret key. The decryption device <b>20</b><i>a </i>may first decrypt the secret key using the private key of the receiver R and then use the decrypted secret key for decrypting the document. Also in this example, the public key and the private key of the receiver R may be generated using the biometric information of the receiver R as described above with reference to <figref idref="DRAWINGS">FIG. 6</figref>.

0120In yet another example, the encryption device <b>10</b><i>a </i>and the decryption device <b>20</b><i>a </i>may exchange a shared secret key for encrypting and decrypting the document according to Diffie-Hellman key exchange algorithm. The public key and the private key of the receiver R used within the Diffie-Hellman key exchange algorithm may be generated using the biometric information of the receiver R as described above with reference to <figref idref="DRAWINGS">FIG. 6</figref>. After exchanging the shared secret key according to Diffie-Hellman key exchange algorithm, the encryption device <b>10</b><i>a </i>can encrypt the document with the shared secret key and the decryption device <b>20</b><i>a </i>can decrypt the document with the shared secret key.

0121Further, for example, in the exemplary embodiments described above with reference to <figref idref="DRAWINGS">FIGS. 1 to 9</figref>, the database <b>50</b> is connected to the encryption device <b>10</b> or <b>10</b><i>a </i>(hereinafter, the “encryption device <b>10</b>” may refer also to the “encryption device <b>10</b><i>a</i>” unless otherwise noted) via the network <b>40</b>. However, in variations of these exemplary embodiments, the database <b>50</b> may be connected to the encryption device <b>10</b> via a network separate from the network <b>40</b>. Alternatively, the database <b>50</b> may be provided within the encryption device <b>10</b>. In these variations, when the decryption device <b>20</b> or <b>20</b><i>a </i>(hereinafter, the “decryption device <b>20</b>” may also refer to the “decryption device <b>20</b><i>a</i>” unless otherwise noted) needs to store the biometric information or public key in the database <b>50</b>, the decryption device <b>20</b> may send the biometric information or the public key to the encryption device <b>10</b> via the network <b>40</b>. The encryption device <b>10</b> may then store the biometric information or the public key.

0122Further, for example, in the exemplary embodiments with symmetric-key cryptography as described above with respect to <figref idref="DRAWINGS">FIGS. 2 to 5</figref>, the database <b>50</b> may store the biometric information including features extracted from human characteristics such as a fingerprint, an image of an eye, an image of a face, an image of palm veins, a palm print or a voiceprint. Alternatively or in addition, the database <b>50</b> may store image data of the human characteristics from which the features can be extracted as the biometric information. For example, an image of a fingerprint, an image of an eye, an image of a face, an image of palm veins, an image of a palm print, or an image of a voice print may alternatively or additionally stored in the database <b>50</b>. The encryption device <b>10</b> may extract features from the image data stored in the database <b>50</b> and use the extracted features for obtaining the encryption key.

0123The various examples of the decryption device <b>20</b> as described above can treat an electronic document E and a physical document P in a same manner. From the perspective of the user, the same set of operations can be required in either case of decrypting an electronic document E or a physical document P. In other words, the user can simply let the biometric detection device <b>24</b> detect his/her biometric information and let the imaging device <b>22</b> of the decryption device <b>20</b> capture the visual representation of the encrypted document, either on a display of the receiver device <b>30</b> or on a physical medium such as paper. Then, provided that the user is the intended receiver of the document, the user can read the decrypted content of the document displayed on the display device <b>28</b> of the decryption device <b>20</b>. Accordingly, the decryption device <b>20</b> in various examples as described herein can make it more convenient for the user to decrypt and read an encrypted document. In other words, the decryption device <b>20</b> in various examples as described herein can provide improved usability.

0124Further, in various examples of the decryption device <b>20</b> as described above, the decryption of the document may be performed using the biometric information of the user. More specifically, the decryption key may be the biometric information itself or be generated from the biometric information. Since the biometric information may be obtained from the human characteristics of the user, the user does not need to memorize or store the decryption key. This can improve the security and the usability. Moreover, since the biometric information can be considered as a kind of identification information of the user and only the biometric information of the intended receiver of the document can result in a successful decryption of the document, a successful decryption using the biometric information can indicate the authenticity of the user. Consequently, the description device <b>20</b> in various examples as described above may not need an additional authentication process for confirming whether or not the user is the intended receiver of the document, which can improve efficiency of the decryption process.

0125The various examples of the decryption device <b>20</b> as described above may be implemented on a mobile device or a wearable device. For example, a mobile device or wearable device may be configured to have the functionalities of any one of the various examples of the decryption device <b>20</b>. As stated above, the mobile device or the wearable device used for implementing the various examples of the decryption device <b>20</b> may be an AR device.

0126In an exemplary implementation using a wearable device as an example of an AR device, the wearable device may be in a form of glasses, such as Google Glass developed by Google Inc. When a glass-style wearable device functions as any one of the various examples of the decryption device <b>20</b>, the biometric information can be detected by scanning at least one eye of the user while the user wears the glass-style wearable device. Further, the decrypted content of the document may be displayed on the glasses having a function of a display device. In this exemplary implementation, all the user needs to do may be simply wear the glass-style wearable device and see the encrypted content of the document on a display of the receiver device <b>30</b> or on a physical medium through the glasses. Then the imaging device on the glasses can capture an image of at least a portion of the encrypted document, decrypt the document using the biometric information detected by scanning at least one eye of the user and display the decrypted content of the document.

0127Further, in various examples of the decryption device <b>20</b> as described above, the decrypted content of the document may be displayed only by the decryption device <b>20</b> and not on a physical medium on which the encrypted content is printed nor on a display of the receiving device <b>30</b> that has received an electronic document E with encrypted content. Consequently, presentation of the decrypted content of the document can be restricted to the display of the decryption device <b>20</b>, which can lead to improved security of the document.

Hardware Configuration

0128The various examples of the encryption device and of the decryption device as described above may be implemented using a computer. The computer may be a general purpose computer such as a personal computer. Alternatively, the computer may be a computer incorporated in a mobile device such as a mobile phone, tablet computer, PDA (personal digital assistant) or laptop computer. In yet another example, the computer may be a computer incorporated in a wearable device. <figref idref="DRAWINGS">FIG. 10</figref> shows an exemplary hardware configuration of a computer that may be used to implement the encryption device and/or the decryption device. The computer shown in <figref idref="DRAWINGS">FIG. 10</figref> includes a processing unit <b>70</b>, a system memory <b>72</b>, a network interface <b>74</b>, a hard disk drive (HDD) interface <b>76</b>, an external disk drive interface <b>78</b> and input/output (I/O) interfaces <b>80</b>. These components of the computer are coupled to each other via a system bus <b>82</b>. The processing unit <b>70</b> may perform arithmetic, logic and/or control operations by accessing the system memory <b>72</b>. The processing unit <b>70</b> may implement the processors of the exemplary encryption device and/or decryption device described above. The system memory <b>72</b> may store information and/or instructions for use in combination with the processing unit <b>70</b>. The system memory <b>72</b> may include volatile and non-volatile memory, such as a random access memory (RAM) <b>720</b> and a read only memory (ROM) <b>722</b>. A basic input/output system (BIOS) containing the basic routines that helps to transfer information between elements within the general purpose computer, such as during start-up, may be stored in the ROM <b>722</b>. The system bus <b>82</b> may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures.

0129The computer may include a network interface <b>74</b> for communicating with other computers or devices via a network.

0130Further, the computer may include a hard disk drive (HDD) <b>84</b> for reading from and writing to a hard disk (not shown), and an external disk drive <b>86</b> for reading from or writing to a removable disk (not shown). The removable disk may be a magnetic disk for a magnetic disk drive or an optical disk such as a CD ROM for an optical disk drive. The HDD <b>84</b> and the external disk drive <b>86</b> are connected to the system bus <b>82</b> by a HDD interface <b>76</b> and an external disk drive interface <b>78</b>, respectively. The drives and their associated computer-readable media provide non-volatile storage of computer-readable instructions, data structures, program modules and other data for the general purpose computer. The data structures may include relevant data for the implementation of the method for encrypting and/or decrypting a document, as described herein. The relevant data may be organized in a database, for example a relational or object database.

0131Although the exemplary environment described herein employs a hard disk (not shown) and an external disk (not shown), it should be appreciated by those skilled in the art that other types of computer readable media which can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, random access memories, read only memories, and the like, may also be used in the exemplary operating environment.

0132A number of program modules may be stored on the hard disk, external disk, ROM <b>722</b> or RAM <b>720</b>, including an operating system (not shown), one or more application programs <b>7202</b>, other program modules (not shown), and program data <b>7204</b>. The application programs may include at least a part of the functionality as described above.

0133The computer may also include an imaging device <b>90</b> such as a camera, an input device <b>92</b> such as mouse and/or keyboard and a display device <b>94</b> such as liquid crystal display. The imaging device <b>90</b>, the input device <b>92</b> and the display device <b>94</b> may be connected to the system bus <b>82</b> via I/O interfaces <b>80</b><i>a </i>to <b>80</b><i>c. </i>

0134In addition or as an alternative to an implementation using a computer as shown in <figref idref="DRAWINGS">FIG. 10</figref>, a part or all of the functionality of the exemplary embodiments described herein may be implemented as one or more hardware circuits. Examples of such hardware circuits may include but are not limited to: Large Scale Integration (LSI), Reduced Instruction Set Circuits (RISC), Application Specific Integrated Circuit (ASIC) and Field Programmable Gate Array (FPGA).

0135The subject matter described in the application can be implemented as a method or as a system, possibly in the form of one or more computer program products. The subject matter described in the application can be implemented in a data signal or on a machine readable medium, where the medium is embodied in one or more information carriers, such as a CD-ROM, a DVD-ROM, a semiconductor memory, or a hard disk. Such computer program products may cause a data processing apparatus to perform one or more operations described in the application.

0136In addition, subject matter described in the application can also be implemented as a system including a processor, and a memory coupled to the processor. The memory may encode one or more programs to cause the processor to perform one or more of the methods described in the application. Further subject matter described in the application can be implemented using various machines.