TECHNICAL FIELD

The present invention relates to a method for checking the validity of a ticket. Such methods are used for example in local public transport and/or in rail transport in order to check the validity of electronic tickets.

An electronic ticket is usually a ticket which is purchased by means of a mobile device, such as for example a mobile phone and/or a tablet PC. Alternatively, the ticket can also be purchased at the PC and subsequently transmitted to the mobile device. In contrast to the conventional ticket, which is printed out on paper and is conventionally supplied with additional security features, such as for example a hologram or the like, electronic tickets are represented on a display device of the mobile device. Contents that are represented on the display device of the mobile device are reproducible as desired, for which reason a ticket represented merely on the display device can be copied as many times as desired.

STATE OF THE ART

In order to make it more difficult to copy a ticket represented on the display device of the mobile device, currently a two-factor authentication method is used for example in trains of the Deutsche Bahn, in which an owner of the electronic ticket must always present said ticket in combination with a second factor. The second factor is, for example, an identification card of the user, a credit card of the user or a discount card of the user (BahnCard). Since the credit card and/or the discount card is a card that is unique and individual for the user, it can be ensured that only the owner of this card employs the electronically purchased ticket. Since it sometimes takes a very long time for the user to present not only the ticket, but also the credit card or discount card, ticket inspectors sometimes forgo a “proper” ticket inspection, limiting the check to a visual inspection of the ticket effected with the naked eye. Since electronic tickets are predominantly present in the form of so-called QR codes, these cannot be detected and verified with the naked eye.

In this respect, the prior art has the disadvantage that a proper inspection is not carried out due to the high time consumption of the inspection.

STATEMENT OF THE INVENTION

It is the object of the invention to make available a method for checking the validity of a ticket and a mobile device which is able to solve the problems of the state of the art and is further adapted to render the checking of an electronic ticket easier and more secure while maintaining high security standards.

The object is achieved by the subject matter of the independent claims. Preferred embodiments result from the dependent claims.

The invention is based on the fundamental idea that the mobile device receives an information item from a ticket inspector during the ticket inspection, processes said information off line, i.e. without online data connection, and makes a code available to the ticket inspector on the basis of said information, which enables the ticket inspector to check the validity of the ticket.

Accordingly, the process for checking the validity of an electronic ticket comprises transferring an information item, in particular a ticket-inspection-process initiation information, from a control entity, in particular a ticket checking device, to a mobile device; computing a code that is individual for the mobile device in the mobile device with the aid of the information, wherein in the mobile device a key is stored which is incorporated in the computation of the individual code, wherein the key is formed from a key stored on a server (master key) and at least one property that is individual for the mobile device; representing the code on the mobile device and/or transmitting the code from the mobile device to the control entity over an air interface, in particular on a display device and/or a contactless transmission device (BLE) of the mobile device; and the checking of the code by the control entity.

According to the invention the control entity is for example a ticket checking device as usually employed by ticket inspectors. Such a checking device can be a specially developed device and/or a mobile device such as for example a mobile phone. Alternatively, the control entity can be arranged at the entrance of a transport means, to check all passengers entering there. By transferring the ticket-checking-process initiation information it is communicated to the mobile device that a ticket check is to be effected.

A ticket-checking-process initiation information item is, for example, a challenge, in particular a random number. This ticket-checking-process initiation information can be transmitted contactlessly from the control entity to the mobile device for example via Bluetooth, in particular BLE, and/or by reading/photographing.

With the method according to the invention it is possible to ensure particularly advantageously that information from both the server and about properties individual for the mobile device are incorporated in the computation of the code individual for the mobile device. In this way it can be ensured with advantage that the mobile device which has purchased the electronic ticket or for which this electronic ticket was purchased, is also used in the check of the validity of the electronic ticket. If a different user with a different mobile device was checked, the computed code would be different, since not only the key is incorporated in the computation of the code, but also the properties individual for the mobile device. Accordingly it can be ensured with advantage that only the “right” mobile device is used in the check.

The representation of the code on the mobile device can be effected both visually, i.e. in optically perceivable manner, for example in the form of a code readable from the display device, and/or on a contactless transfer device, such as for example a BLE (Bluetooth Low Energy) or an NFC transfer device. The representation on the contactless transfer device has the advantage that the code can be immediately transmitted back to the control entity and represented there.

According to one embodiment, the transfer of the information from the control entity to the mobile device is effected by reading and/or by photographing the information from a display device of the control entity. Alternatively, according to a further embodiment, the transfer of the information from the control entity to the mobile device can be effected via a contactless information exchange, in particular over an air interface, for example by means of NFC, Bluetooth and/or WLAN. By means of these variants it is ensured that the transfer of information can be effected in a simple manner. Thus, for example the photographing of the information by means of the mobile device of the user is a common means already today to ascertain the information from a QR code, such as for example attached to an advertising poster. Alternatively, the user can also read the information from the control entity and input it manually on his mobile device, wherein a readable information item is a multi-digit number or the like. The contactless transfer of the information over an air interface represents a secure, fast and reliable transmission channel. In particular, the transfer via, for example, the NFC interface could be effected in accordance with a so-called tap-it method, in which two NFC-enabled devices approach each other for a short time in order to permit an exchange of information.

According to one embodiment, the information and/or the code is a machine-readable information item, preferably a QR code, particularly preferably an Aztec code, and/or a manually transferable information item, such as a multi-digit, in particular a four-digit, number. The multi-digit number is advantageous particularly when the information is read by the user, since it can be read and input on the mobile device quickly.

The mobile device can be a mobile phone, a tablet PC and/or a smart phone.

To ensure with advantage that the method according to the invention is also effected when mobile data are not available, the method is adapted such that the key is stored in the mobile device, preferably in a secure area, and is replaced only from time to time, i.e. at regular intervals, for example every few days and/or months, when a data connection is present. The key in the mobile device is generated in a server instance together with an individual property of the mobile device, for example the IMEI, the processor serial number and/or the MAC address of the mobile device, and the certificate is signed by a further key remaining in the server. When the key is generated, a PKI method is used among other things, in which the mobile device has a private key and the control entity has a public key.

Correspondingly, in accordance with one embodiment it is possible with advantage to carry out the individual code exclusively employing the data already present on the mobile device at the time of transfer of the information from the control entity to the mobile device. In other words, for computing the individual code no online data connection (in other words a data connection via the MNO) needs to be utilized, and the method can be executed with advantage also in regions where there is no or only a limited data connection. The transmission and/or transfer via Bluetooth, in particular BLE (Bluetooth Low Energy) is always possible.

According to one embodiment, the control entity is a ticket checking device. In this way it is ensured with advantage that ticket devices available already today can be used in a method according to the invention after a software update. Alternatively, the control entity can be a mobile phone and/or a smart phone.

According to a further particularly preferred embodiment, a ticket purchase at a ticket server is effected prior to transferring the information, wherein, after completing the purchase, a ticket information item, in particular a ticket form in the form of a machine-readable code, is transferred to the mobile device. In this way, the user is in possession of an electronic ticket, which he can present when required in an inspection. In this case, an inspection method could be performed as well in which the ticket is checked in the form of a machine-readable code in combination with an identity card or the like.

Accordingly, the ticket information can be incorporated additionally in the computation of the control code. Thus, the control entity can check with advantage whether the current ticket information is present on the mobile device. Subsequently, when the code is represented on the mobile device, this code can differ barely noticeably from the hitherto representable ticket prima facie. The user merely perceives the change of individual pixels and is thus aware that the computation of the new control code has been carried out. For an inspector this can likewise be an indication that his new code has been computed.

According to a further particularly preferred embodiment, the representation of the (control) code on the mobile device comprises the representation of the ticket information. In other words, the code and the ticket information can be processed to form one information item which is then represented on the display device of the mobile device, for example in the form of a single QR code. Alternatively, the ticket information and the code can be represented in the form of two separate information items on the display device of the mobile device. Of course, it is also possible to represent the code and the ticket information consecutively (in any order) on the display device, i.e. offset in time. The transmission of the code from the mobile device to the control entity over the air interface is understood equivalently to the concept of representing the code on the mobile device.

According to the invention, the property individual for the mobile device can be data which are protected in the mobile device against copying and/or unauthorized use. Consequently, the method is protected against unauthorized use.

The advantages of the invention are also apparent in a mobile device which is adapted to receive an information item from a control entity, wherein the mobile device is configured to compute, by means of a computing unit, a code that is individual for the mobile device, while employing the information, wherein the mobile device has a memory in which a key can be stored that is incorporated in the computation of the individual code, wherein the computation is effected by means of a computing unit (CPU), wherein the key is executed such that it is formed from a key stored on a server and from at least one property individual for the mobile device, and wherein the mobile device is configured to represent the code on a display device of the mobile device and/or to transmit the code from the mobile device to the control entity over an air interface. In the code, further features can be incorporated, such as for example a signature of the key of the server.

Accordingly, it is possible with the mobile device with advantage to take part in a ticket inspection in which the mobile device has to prove that it is in possession of the valid ticket. Additional authentication features, such as for example a credit card and/or a discount card, are not required. This reduces substantially the time required for an inspection of the ticket present on the mobile device. Consequently, ticket inspectors are more inclined to carry out a proper check of a ticket with the control entity, in particular with the ticket checking device.

The method according to the invention is particularly suitable for employment in a mobile device and/or in a control entity for checking electronic tickets or tickets for transport means.

