WO2012005653A1

WO2012005653A1 - Secure user identification

Info

Publication number: WO2012005653A1
Application number: PCT/SE2011/050686
Authority: WO
Inventors: Joel SANDSTRÖM
Original assignee: Nordic Wallet Ab
Priority date: 2010-07-09
Filing date: 2011-06-01
Publication date: 2012-01-12
Also published as: SE535009C2; SE1050777A1

Abstract

A system (1) for secure identification of a user (2) includes a mobile terminal (10) which is operatively connected to a telecommunications network (30) and to a data network (40). The system also includes a local device (20) which is operatively connected to the data network; and a server side (50) comprising at least one server (52a-n) operatively connected to the data network and at least one server (52a-n) operatively connected to the telecommunications network. The server side (50) is configured to initiate a communication session (42) with the local device (20) over the data network (40), said communication session having a session ID, to generate a representation (24) of the session ID and to transmit the representation to the local device over said data network. The local device (20) is configured to present the representation in a user interface (22) of the local device. The mobile terminal (10) is configured to capture the presented representation so as to derive the session ID, and to send a message containing the derived session ID to the server side over the data network. The server side is further configured to determine an identity of the mobile terminal on the telecommunications network, to verify the determined mobile terminal identity against prestored reference data (56) which links the mobile terminal identity to private user information (54) pertaining to the user (2), and, upon successful verification, to associate the communication session with the private user information.

Description

Secure user identification

Technical Field

The present invention relates to a system for secure identification of a user, invention also relates to corresponding methods and associated computer program products.

Background

The innovation generally relates to the problem of providing secure identification of a user. As is well known per se, a digital identity is used for various purposes, for instance bank login, web page login, signing of payment transactions, signing of real world (retail store) transactions, access to personal digital services, etc. All computerized services based on private user information stored in an account require and make benefit of a secure login or signing to access the private user information. Today and in the future more digital services will be available outside the world wide web and be more integrated into real life. Flying with an airline today is an example of a digital service where no pre-printed ticket is needed.

Taking bank login as an example, the prevailing existing solutions make use of a separate portable authenticator or code generator (for instance VASCO DIGIPASS, which is used by the Swedish banks SEB and Swedbank). A user who wants to login to his bank account will use a web client in a local device, such as a handheld, laptop or stationary computer, to visit the web site of the bank and select a login form. The bank server will initiate a secure web session with the local device. In order to complete the establishment of the secure web session, the bank server will require a secure identification of the user. To this end, the user will have to enter some personal identification data in the web login form, such as his social security number. Moreover, the user will enter a PF code on his portable code generator together with at least one control code shown by the bank server in the login form on the local device. In response, the portable code generator will output a random code that the user reads and then enters into the login form on the local device. The bank server will authenticate the user by verifying that the entered random code matches the control code and has been generated by the particular code generator previously linked to the particular user having the entered personal identification data.

There are several drawbacks with this prior art solution. Firstly, the user will have to bring and keep track of a separate device, namely the portable code generator, which is inconvenient for logistic reasons.

Secondly, the solution requires several steps of manual interaction by the user. In the example above, the user will first have to enter his PIN code on a miniature keypad of the portable code generator. Such activity is prone to input errors caused by the user pressing another key than the intended one. Then, the user will enter his personal identification data in the login form. After that, the user will have to visually read the generated control code on the display of the local device and correctly enter each digit thereof on the keypad of the portable code generator - again an activity which is exposed to input errors. Finally, the user will have to read the generated random code from a small, monochrome display on the portable code generator (which may be difficult particularly when the ambient light conditions are poor, or if the user is a visually impaired person), and correctly enter each digit of the random code into the login form on the local device.

Thirdly, the solution is far from user friendly, since it is designed and dictated solely by the service provider (the bank) and not by or for the user and his need for a convenient solution.

Fourthly, there is a security issue due to the fact that the control code which the user reads from the local device and enters on his code generator must be limited in length for practical reasons. The more digits in the control code, the higher the risk that the user makes an input error by pressing the wrong key on the keypad of the code generator. However, a more complex (e.g. longer) control code would have been preferred from a data security point of view, since that would provide for a broader code space which is harder to break.

Fifthly, a personal integrity issue lies in the fact that the user has to reveal his personal identification data, e.g. his social security number, during the login procedure.

The present inventors have realized that there is room for improvements with respect to these problems, not only as regards the bank login example referred to above, but also when it comes to providing secure identification of a user in general.

Summary

It is accordingly an object of the invention to eliminate or alleviate at least some of the problems referred to above.

As a conceptual idea behind the invention, the present inventors have realized that the manual steps required by a user to securely identify himself to a server side can be considerably reduced. The present inventors have also realized that the need for a separate portable authenticator or code generator can be eliminated. Instead, inventive use can be made of a mobile terminal and its unique identity on a telecommunications network.

This conceptual idea has been reduced to practice at least according to the aspects and embodiments of the invention referred to below.

One aspect of the present invention therefore is a system for secure

identification of a user, the system comprising: a mobile terminal which is operatively connected to a telecommunications network and to a data network; a local device which is operatively connected to the data network; and a server side comprising at least one server operatively connected to the data network and at least one server operatively connected to the telecommunications network. This system is characterized in that the server side is configured to initiate a communication session with said local device over said data network, said communication session having a session ID, to generate a representation of the session ID and to transmit the representation to the local device over said data network. The local device is configured to present the representation in a user interface of said local device. The mobile terminal is configured to capture the presented representation so as to derive said session ID, and to send a message containing the derived session ID to the server side over said data network. The server side is further configured to determine an identity of the mobile terminal on the telecommunications network, to verify the determined mobile terminal identity against prestored reference data which links the mobile terminal identity to private user information pertaining to said user, and, upon successful verification, to associate said communication session with said private user information.

In one or more embodiments, the data network is comprised in the Internet or is compatible therewith. The local device may be a computer having a web client application (such as Internet Explorer, Mosaic, Netscape Navigator, Netscape

Communicator, Opera, Mozilla Navigator, Mozilla Firefox, Safari or Google Chrome). The communication session may be a secure web session (such as an HTTPS

(Hypertext Transfer Protocol Secure) session over TLS (Transport Layer Security) or SSL (Secure Sockets Layer (SSL). However, the invention is expressly not limited to communication sessions of this kind only, as will be clear from later sections of this document.

It is to be emphasized that the term "session ID" is not limited to any particular format or constitution within the context of the present invention. Generally, any piece of data will qualify as "session ID", so long as it a) serves to identify the communication session for the server side, b) can be included in the representation sent to the local device, and c) can be derived by the mobile terminal having captured the presented representation on the local device.

In one or more embodiments, the telecommunications network is compliant with one or more standards selected from the group consisting of: GSM, UMTS, LTE, D-AMPS, CDMA2000, FOMA or TD-SCDMA. However, within the context of the present invention, the scope of "telecommunications network" is not limited to any of these standards. On the contrary, any network capable of conveying communication with or between mobile devices is to be regarded as a "telecommunications network", so long as the network has intelligence which is capable of assigning and detecting unique identities of mobile devices included in the network, and is capable of detecting when multiple mobile devices with the same identity attempt to access the network.

In one or more embodiments, the mobile terminal is configured to include, in the message which contains the derived session ID and is sent on the data network, information about the mobile terminal identity it has on the telecommunications network. The server side is configured to use this information which is included in said message when verifying the determined mobile terminal identity against the prestored reference data. In other words, the server side bases its authentication of the mobile terminal both on the identity of the mobile terminal as reported in the message over the data network and on the identify of the mobile terminal as detected on the telecommunications network. This prevents malicious attempts to use another mobile terminal's identity. The mobile terminal identity may for instance be the IMSI (International Mobile Subscriber Identity) stored on the SIM card in the mobile terminal, or the mobile terminal's hardcoded IMEI (International Mobile Equipment Identity), or basically any prestored unique identity information in the mobile terminal which is detectable by the telecommunications network and which cannot be manipulated by a user.

In one or more embodiments, the server side is configured to generate the representation of the session ID in the form of graphical image data which contains an encoded version of the session ID and which can be visually presented on a display of the local device. Advantageously, the graphical image data is a two-dimensional barcode such as a Quick Response (QR) code. However, other formats for the

representation of the session ID are possible in other embodiments, including other graphical image formats but also non- visual formats such as for instance audio formats. Basically, any data format for the representation of the session ID is feasible, provided that it i) can be transmitted by the server side to the local device over the data network, ii) can the presented by the local device in a user interface thereof (such as a display screen or a loudspeaker), and iii) can be captured by the mobile terminal (using for instance a camera or a microphone) and processed in order to derive the included session ID.

A second aspect of the invention is a method of secure identification of a user having access to a mobile terminal operatively connected to a telecommunications network, and to a local device operatively connected to a data network. The method comprises the steps, at a server side operatively connected to said data network and said telecommunications network, of:

initiating a communication session over the data network with the local device, said communication session having a session ID;

generating a representation of the session ID in a format suitable for presentation in the user interface of the local device, in turn suitable for capture by the mobile terminal upon presentation in said user interface so as to derive the session ID included in said representation;

transmitting the representation to the local device over said data network; receiving from the mobile terminal over said data network a message containing the derived session ID;

determining an identity of the mobile terminal on the telecommunications network;

verifying the determined mobile terminal identity against prestored reference data which links the mobile terminal identity to private user information pertaining to said user; and

upon successful verification, associating said communication session, having the derived session ID, with said private user information.

A third aspect of the invention is a computer program product comprising computer program code for performing the method according to the second aspect of the invention when said computer program code is executed by a processor.

A fourth aspect of the invention is a method of secure identification of a user having access to a mobile terminal operatively connected to a telecommunications network, and to a local device operatively connected to a data network. The method comprises the steps, in said mobile terminal, of:

capturing data presented in the user interface of the local device; processing the captured data to derive a session ID included therein, wherein the session ID represents a communication session over the data network between the local device and a server side;

sending a message containing the derived session ID to the server side over the data network; and

cooperating with the server side to allow determination of an identity of the mobile terminal on the telecommunications network.

A fifth aspect of the invention is a computer program product comprising computer program code for performing the method according to the fourth aspect of the invention when said computer program code is executed by a processor.

Embodiments of the second to fifth aspects of the invention may generally have the same or directly corresponding features as any of the features referred to above for the first aspect.

Embodiments of the invention have an advantage in that secure user identification is provided in a logistically improved manner by eliminating the need for a separate code generator.

Another advantage is that secure user identification can be made more efficiently, since the manual interaction required from the user has been reduced.

Still an advantage is an improvement in terms of user friendliness.

Yet an advantage is an improvement in data security, since the steps of manual user interaction to read a control code and enter it on a code generator have been eliminated, which imposed a limitation on the complexity of the control code in the prior art.

Also, there is an advantage in terms of personal integrity, since the user will not have to expose any personal identification data during the login procedure.

Brief Description of the Drawings

Objects, features and advantages of embodiments of the invention will appear from the following detailed description, reference being made to the accompanying drawings, in which:

Fig 1 is a schematic illustration of a non-limiting example of a system for secure identification of a user, in which embodiments of the present invention may be exercised; Fig 2 is a flow chart and signaling diagram illustrating some of the activities and messages which are performed and exchanged in the system of Fig 1 when performing a method for secure identification of a user; and

Fig 3 illustrates a use case where an embodiment of the present invention is used for the purpose of logging in to an Internet bank.

Detailed Description

Embodiments of the invention will now be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein;

rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

The invention will first be described on a general level with reference to a system and a method for secure identification of a user shown in Figs 1 and 2. Then, some more detailed embodiments and use cases will be described.

Fig 1 illustrates a system 1 for secure identification of a user 2. The user 2 will use a local device 20 to access a service provided over a data network 40 by one or more servers 52a, 52b, 52n at a server side 50. The operation of the service is based at least partially on some sort of private user information 54 pertaining to the user 2 and stored in a memory 55 accessible to at least one of the servers 52a-52n. The private user information 54 may for instance relate to a bank account, a payment transaction, or basically any digital asset belonging to or associated with the user 2. The service may for instance be bank login, login to another web service, sign transaction, sign real world transaction (like a VISA card payment), transfer money between users, or using the service as an electronic ticket.

The local device 20 may for instance be a stationary, portable or handheld computer running an appropriate client operating system and provided with software capable of communicating with the user 2 through a user interface 22, as well as with the server side 50 over a communication session 42 on the data network 40, to perform the requested service. Correspondingly, the servers 52a-52n may be any number of server computers or server computer arrays running appropriate server operating system(s) and being capable of providing the requested service to the user 2 over the communication session 42 on the data network 40.

The user 2 also has access to a mobile terminal 10, e.g. a mobile phone, smart- phone or personal digital assistant (PDA). According to the invention, the mobile terminal 10 plays an active role in the secure identification of the user 2. In addition to this, the user 2 may of course use his mobile terminal 10 to conduct voice calls with other users which are accessible through a telecommunications network 30. In addition to voice calls, the user 2 may use various other telecommunications services, such as Internet browsing, video calls, data calls, facsimile transmissions, still image trans- missions, video transmissions, electronic messaging, and e-commerce. None of these telecommunication services are however central within the context of the present invention; there are no limitations to any particular set of services in this respect.

The mobile terminal 10 connects to the telecommunications network 30 over a radio link 34 and a base station 32. The mobile terminal 10 and the telecommunications network 30 may comply with any commercially available mobile telecommunications standard, including but not limited to GSM, UMTS, LTE, D-AMPS, CDMA2000, FOMA and TD-SCDMA. A conventional public switched telephone network (PSTN) with various stationary telephone terminals may be connected to the telecommunications network 30.

The functionality performed in the system 1 in order to provide secure identification of the user 2 can be summarized as follows. Initially, when the service is required by the user 1, a request may be sent from the local device 20 to the server side 50 (see step 202 in Fig 2). In response, the communication session 42 will be established between the server side 50 and the local device 20. The communication session 42 will be assigned a session ID, see step 204 in Fig 2. The communication session 42 may for instance be a secure web session (such as HTTPS TLS or SSL) between a web client in the local device 20 and a web server at the server side 50, but other kinds of communication sessions are also possible. Notably, however, and unlike the prior art approaches referred to in the Background section of this document, the communication session 42 will at this stage not be linked to any particular user, nor to any private user information at the server side 50. Instead, at this early stage, the session 42 will be secure but anonymous in the sense that the server side 50 is unaware of the user or private user information which it is to be associated with.

In order to determine who the session 42 relates to and obtain an authenticated session, the following measures are taken. In step 206, the server side 50 generates a representation of the session ID of the communication session 42. Advantageously, the representation takes the form of graphical image data, preferably a two-dimensional barcode such as a Quick Response (QR) code. However, other alternatives for the representation generated in step 206 are also possible, as has been explained above in the Summary section. In step 208, the server side 50 transmits the representation of the session ID over the data network 40 to the local device 20, as seen at 209. The transmission 209 may be made in accordance with any standard or protocol applicable for the type of communication session in question. For instance, when the session 42 is a web session and the representation is a QR code, the transmission 209 may involve embedding the QR code in html or xml code which is read by the local device 20 from the server side 50. Upon receipt of the transmitted representation at the local device 20, the local device 20 will present the received representation of the session ID in its user interface 22. Continuing with the example given above, this may involve using a web client application in the local device 20 for rendering the received html or xml code and presenting the embedded QR code, as seen at 24 in Fig 1, on a display unit which is part of the user interface 22.

The user 2 may now use his mobile terminal 10 to proceed with his secure identification to the server side 50. Initially, in a step 212, the user 2 will start a secure identification application in his mobile terminal and login, for instance by entering a PIN code. The secure identification application may for instance be a Java applet or midlet, or any other kind of executable piece(s) of software written in an appropriate programming language which is compatible with the operating system of the mobile terminal. The application is responsible for performing or controlling the essential parts of the mobile terminal- side functionality shown in Fig 2.

Thus, in step 214, the user 2 will use his mobile terminal to capture the representation 24 as presented in the user interface 22 of the local device. In the disclosed embodiment where the representation is in the form of a graphical QR code, the capture will be done by taking a photograph of the shown QR code 24 by means of a camera 12 included in the mobile terminal 10. The photograph may be subjected to image pre-processing, if appropriate, in order to enhance the readability of its contents. Then, the mobile terminal will process the representation included in the image by appropriate object recognition algorithms in order to derive the session ID.

In step 216, the mobile terminal 10 will compose a message 217 which contains the derived session ID from step 214. The message 217 will be sent to the server side 50 over an appropriate communication channel, such as a TLS or SSL connection over the data network 40. The message 217 also contains an identifier of the mobile terminal on the telecommunications network 30, for instance its IMSI or IMEI number. Advantageously, the derived session ID, and possibly other content of the message 217, is encrypted with an encryption key stored in the mobile terminal 10. Any open or proprietary encryption standard may be used for such encryption, including but not limited to AES ("Advanced Encryption Standard") or DES ("Digital Encryption Standard"). The encryption key may for instance have been received in the mobile terminal in conjunction with retrieval and installation of the secure identification application in the mobile terminal 10.

On the server side 50, the message 217 is received in step 218 over the data network 40. The message is analyzed to determine the mobile terminal identifier included therein. When encryption has been applied, the server side 50 may use prestored reference data 56 in a secure database 57 to retrieve a decryption key suitable for the mobile terminal 10 in question, as identified by the mobile terminal identifier. Such decryption key may have been stored in the prestored reference data 56 in conjunction with the mobile terminal's 10 retrieval and installation of the secure identification application. Following decryption, if applicable, the derived session ID included in the message 217 is determined in step 218.

In order to verify that the message 217 with its derived session ID truly originates from the mobile terminal 10 and not from another mobile terminal maliciously trying to act as the mobile terminal 10, in step 219 the server side determines the identity of the mobile terminal 10 also via the telecommunications network 30. In other words, the server side 50 uses the inherently secure and non-public nature of the telecommunications network 30 to verify that the IMSI, IMEI, etc, of the mobile terminal 10, as reported in the message 217 over the data network 30, is the same as the IMSI, IMEI, etc, detected for the mobile terminal 10 on the telecommunications network 30.

To this end, the determination in step 219 of the identity of the mobile terminal 10 on the telecommunications network 30 may be done by way of a message such as a data SMS or MMS sent from the mobile terminal 10 (see step 221 in Fig 2) to a telecommunications server included among servers 52a-52n. The server side 50 may retrieve the identity (i.e. the IMSI) of the mobile terminal 10 from the header section of this SMS or MMS message. Alternatively, the determination in step 219 may start with the server side 50 sending a challenge request in a message such as a data SMS or an MMS to the mobile terminal 10 over the telecommunications network 30. Upon receipt, the mobile terminal 10 may generate and send a challenge response over a secure connection on the data network 40 to the server side 50 in step 221. Only the true mobile terminal 10 will receive the challenge request over the telecommunications network 30; therefore, when the server side 50 receives the challenge response, it knows that it must have come from the true mobile terminal 10 and has therefore indirectly determined the mobile terminal's 10 identity on the telecommunications network 30.

Instead of sending a message, the determination of the identity of the mobile terminal 10 on the telecommunications network 30 may involve placing a data call in step 221 from the mobile terminal 10 to the telecommunications server. Upon receiving the incoming data call in step 219, the telecommunications server may determine the identity of the terminal 10 as the Caller Identification (CID), Calling Line Identification (CLID), Calling Number Identification (CNID), etc, depending on implementation.

As still other alternatives, the server side 50 may use other inherent properties of the telecommunications network 30 to determine the identity of the mobile terminal 10 on the telecommunications network 30. This may, for instance, involve referral to system databases which are integral parts of the telecommunications network 30, such as a HLR ("Home Location Register") or VLR ("Visiting Location Register") in which the IMSI and IMEI of mobile terminals in the network 30 are included. This may be combined with determination of the cell ID for the cell in the network 30 that the terminal 10 is currently residing in, and matching with a self-reported cell ID as part of the message 217 over the data network 40. The skilled person will understand that there are many options for determining the true identity of a mobile terminal on a telecommunications network, and the invention is not limited in any particular way.

Once the identity of the mobile terminal 10 on the telecommunications network 30 has been determined in step 219, the server side 50 may verify in step 220 that this identity is the same as the mobile terminal identifier reported in the message 217 over the data network 30. If the secure identification application is copied to other devices or computers than the true mobile terminal 10, or if a communication is started by someone simulating the application, the server side 50 will know that the communication is not sent by the true mobile terminal 10. Even though the communication sent by the intruder will simulate all information sent through the data network 40 (wherein the server side 50 may fail to detect that data is sent by someone else than the true user 2 on the data network 40), the server side 50 will nevertheless detect that the application does not communicate using the true mobile terminal on the telecommunications network 30. The server side 50 will therefore know that the communication is not sent by the verified hardware.

Moreover, in step 220, the determined mobile terminal identity will be verified against the prestored reference data 56 which links the mobile terminal identity to the private user information 54 that pertains to the user 2 and is stored in the memory 55. Upon successful verification in step 220, the communication session 42 as created in step 204 can be associated with the private user information 54 of the user 2 in a subsequent step 222. This can be done through the use of the session ID, which was assigned to the communication session 42 in step 204 and which is also available in the message 217 reported from the mobile terminal 10 to the server side 50 after capturing of the representation of the session ID on the local device 20. As a result of step 222, the secure communication session 42 has now become an authenticated session, see step 224, in the sense that it is now associated at the server side 50 with the particular user 2 and his private user information 54.

The secure user identification procedure described above requires retrieval and installation of a secure identification application in the mobile terminal. In embodiments of the invention, this may be done in a secure and yet convenient manner in the following manner. First, the user 2 will download the software that will constitute the secure identification application to his mobile terminal 10. This may be done in the conventional way, e.g. in a web session, an ftp session, as an attachment to an email message, over a serial interface such as USB, etc. Alternatively, it may for instance be done by scanning a QR-coded version of the software being presented at for instance a web site and interpreting the scanned QR code as software code.

The thus obtained software will then be installed in the mobile terminal 10. The user 2 may advantageously be prompted to set a PIN code to be used for subsequent uses of the secure identification application (e.g. in login step 212 of Fig 2).

During installation, or the first time the application is run, the user 2 will be advised to establish a secure web session between the local device 20 and the server side 50 over the data network 40. When the server side 50 is an Internet bank, the user 2 may be prompted with an essentially conventional login screen, where the user 2 is asked to enter his personal identification data, read a presented control code and enter it on his code generator, and then enter the random code generated by the code generator - much like the prior art approach described in the Background section of this document. However, unlike the prior art approach, the server side 50 will generate a QR code and show it on the local device 20. The user 2 will be prompted to scan the QR code using the built-in camera of his mobile terminal 10.

The mobile terminal 10 will respond to the server side 50 in a handshake operation, in which the scanned QR code is sent together with an identifier (e.g. IMSI, IMEI) of the mobile terminal 10 over the data network 30. In return, in implementations where encryption is used for the exchange of information in steps 216-218 of Fig 2, the server side 50 will respond with an encryption key to be stored in local and preferably secure memory in the mobile terminal 10. The server side 50 may also verify the received mobile terminal identifier by determining the identity of the mobile terminal 10 on the telecommunications network 30 in much the same way as has been described above with reference to steps 219-221 of Fig 2. Upon successful verification, the server side 50 may insert or update a record in the prestored reference data 56 to create a link between the user 2, the identity of his mobile terminal 10 and his private user information 54. From now on, the user 2 will no longer need to use his code generator for logging in to his Internet bank (etc); instead he can conveniently log in by using his mobile terminal and capturing QR codes with the built-in camera.

Fig 3 illustrates a use case where the user 2 makes beneficial use of the present invention when logging in to his Internet bank from a local device 20. In the situation shown in Fig 3, the user 2 has already requested a secure web session with the bank server at the server side 50 by for instance clicking on a "Login with my Phone" link on the home page of the Internet bank in question. In other words, steps 202 and 204 of Fig 2 have already been performed. In response, the bank server initiates the communication session 42 and assigns its session ID. Also see step 204 of Fig 2. The bank server also generates the representation of the session ID in the form of a QR code 24, and transmits it to the local device 20. Upon receipt, the local device 20 presents the QR code 24 in its user interface 22. See steps 206-210 of Fig 2. Possibly encouraged by an alert in the user interface 22 of the local device 20, or merely triggered by the appearance of the QR code 24, the user 2 turns to his mobile terminal 10 and launches the secure identification application, see step 212 of Fig 2. This is illustrated at the leftmost solid circle "1" in Fig 3. The user 2 also enters his PIN code in the user interface of the mobile terminal 10.

As is illustrated at the centered solid circle "2" in Fig 3, the user 2 scans the QR code 24 by using the built-in camera 12 of this mobile terminal to capture an image (photograph). What follows now are steps 214 through 222 of Fig 2, ending with a successful authentication of the communication session 42 in step 224. This also means that the user 2 has been signed in to his bank account represented by his private user information 54 at the bank server. See the rightmost solid circle "3" in Fig 3.

This use case illustrates utterly well some of the merits of the invention, thanks to the simplicity and convenience of the interaction performed by the user 2. Various other use cases are however equally possible within the scope of the invention. For instance, one such alternative use case is when the user 2 has already logged in to his Internet bank and now wants to sign a bank transaction, such as the payment of an invoice by way of a giro transfer. The procedure is very similar; when it is time to request a signature of the transaction from the user 2, the bank server will initiate a secure session for the transaction; a QR code representing the session ID of this session will be transmitted to the local device 20 and shown on its display; the user 2 will scan the QR code with his mobile terminal 10; and, at the end, the server side 50 will regard the transaction session as authenticated and, in effect, the transaction as duly signed by the user 2.

A similar alternative use case is sign in to other web services or accounts than

Internet bank-related ones. Essentially the same process is used for sign in to such other web services or accounts.

Still another alternative use case is payment in conjunction with e-commerce. A user enters a store on an Internet site and wants to complete a purchase. The Internet store requests an ID from an ID server comprised among the servers 52a-52n at the server side 50. The user uses his mobile terminal and scans the QR code displayed in the web browser. The displayed QR code includes information about the ID. The user's application in the mobile terminal sends the scanned ID to the ID server. The ID server now knows who scanned the QR code. It also receives information from the

telecommunications network telling it that the application is still running on the registered mobile terminal. If connected to the user's bank or bank account, the ID server can now withdraw money from the user. The ID server then sends information to the Internet store about the completed transaction. Finally, the Internet store can display information about the successful payment and complete the purchase.

Yet another alternative use case is payment in real life. The approach provided by the invention is applicable also to payments in real world. The cash register or terminal acts as the local device and displays a QR code. There now exists a communication session in the form of a "cash terminal - server" session instead of a web session. The method described above with reference to Fig 2 may be embodied as a computer program product comprising computer program code for performing the server-side parts of the method when the computer program code is executed by a processor, for instance embodied in any of the servers 52a-52n in Fig 1. The method may also be embodied as a computer readable medium having stored thereon a computer program comprising computer program code for performing the method when the computer program code is executed by a processor. Again the processor may for instance be embodied in any of the servers 52a-52n in Fig 1. The computer readable medium may for instance be any of the memories 55, 57 in Fig 1, or another plausible medium including but not limited to an optical disc (e.g. CD or DVD), a portable semiconductor memory (e.g. USB stick), a magnetic disc, or a file server accessible in a computer network such as the Internet.

Furthermore, the method described above with reference to Fig 2 may be embodied as a computer program product (e.g. a phone app) comprising computer program code for performing the mobile terminal parts of the method when the computer program code is executed by a processor in the mobile terminal 10. The method may also be embodied as a computer readable medium having stored thereon a computer program comprising computer program code for performing the method when the computer program code is executed by a processor in the mobile terminal 10. The computer readable medium may be any plausible medium including but not limited to an optical disc (e.g. CD or DVD), a portable semi-conductor memory (e.g. USB stick), a magnetic disc, or a file server accessible in a computer network such as the Internet.

The invention has been described above in detail with reference to

embodiments thereof. However, as is readily understood by those skilled in the art, other embodiments are equally possible within the scope of the present invention, as defined by the appended claims.

Claims

1. A system (1) for secure identification of a user (2), the system comprising: a mobile terminal (10) which is operatively connected to a telecommunications network (30) and to a data network (40);

a local device (20) which is operatively connected to the data network; and a server side (50) comprising at least one server (52a-n) operatively connected to the data network and at least one server (52a-n) operatively connected to the telecommunications network, the system being characterized in that

the server side (50) is configured to initiate a communication session (42) with said local device (20) over said data network (40), said communication session having a session ID, to generate a representation (24) of the session ID and to transmit the representation to the local device over said data network;

the local device (20) is configured to present the representation in a user interface (22) of said local device;

the mobile terminal (10) is configured to capture the presented representation so as to derive said session ID, and to send a message containing the derived session ID to the server side over said data network; and

the server side (50) is further configured to determine an identity of the mobile terminal on the telecommunications network, to verify the determined mobile terminal identity against prestored reference data (56) which links the mobile terminal identity to private user information (54) pertaining to said user (2), and, upon successful verification, to associate said communication session with said private user information.

2. The system according to claim 1, wherein:

said data network (40) is comprised in the Internet or is compatible therewith; said local device (20) is a computer having a web client application; and said communication session (42) is a secure web session.

3. The system according to claim 1 or 2, wherein:

said telecommunications network (30) is compliant with one or more standards selected from the group consisting of: GSM, UMTS, LTE, D-AMPS, CDMA2000, FOMA or TD-SCDMA.

4. The system according to any preceding claim, wherein: the mobile terminal (10) is configured to include, in the message which contains the derived session ID and is sent on the data network, information about the mobile terminal identity it has on the telecommunications network; and

the server side (50) is configured to use this information which is included in said message when verifying the determined mobile terminal identity against the prestored reference data.

5. The system according to any preceding claim, wherein:

the server side is configured to generate the representation (24) of the session ID in the form of graphical image data which contains an encoded version of the session ID and which can be visually presented on a display (22) of the local device (20).

6. The system according to claim 5, wherein:

the graphical image data is a two-dimensional barcode such as a Quick

Response (QR) code.

7. A method of secure identification of a user (2) having access to a mobile terminal (10) operatively connected to a telecommunications network (40), and to a local device (20) operatively connected to a data network (30), the method comprising the steps, at a server side (50) operatively connected to said data network and said telecommunications network, of:

initiating (204) a communication session (42) over the data network with the local device, said communication session having a session ID;

generating (206) a representation (24) of the session ID in a format suitable for presentation in the user interface (22) of the local device, in turn suitable for capture by the mobile terminal (10) upon presentation in said user interface so as to derive the session ID included in said representation;

transmitting (208) the representation to the local device over said data network; receiving (218) from the mobile terminal over said data network a message (217) containing the derived session ID;

determining (219) an identity of the mobile terminal on the telecommunications network (40);

verifying (220) the determined mobile terminal identity against prestored reference data (56) which links the mobile terminal identity to private user information (54) pertaining to said user (2); and upon successful verification, associating (222) said communication session, having the derived session ID, with said private user information.

8. A computer program product comprising computer program code for performing the method according to claim 7 when said computer program code is executed by a processor (52a-52n).

9. A method of secure identification of a user (2) having access to a mobile terminal (10) operatively connected to a telecommunications network (40), and to a local device (20) operatively connected to a data network (40), the method comprising the steps, in said mobile terminal (10), of:

capturing (214) data presented in the user interface (22) of the local device

(20);

processing (214) the captured data to derive a session ID included therein, wherein the session ID represents a communication session (42) over the data network between the local device and a server side (50);

sending (216) a message (217) containing the derived session ID to the server side over the data network; and

cooperating (221) with the server side to allow determination of an identity of the mobile terminal on the telecommunications network (30).

10. A computer program product comprising computer program code for performing the method according to claim 9 when said computer program code is executed by a processor (10).