Secure network connection allowing choice of a suitable security algorithm

The invention provides for a method for use in a mobile radio communications device network connection procedure and including the step of, at a network, sending to a mobile radio communications device a list of a plurality of security algorithms supported in the network and so as to allow choice of a suitable algorithm irrespective of the degree of update that the device may have experienced.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/JP2010/061097 filed on Jun. 23, 2010, which claims priority from United Kingdom Patent Application No. 0911118.8, filed on Jun. 29, 2009, the contents of all of which are incorporated herein by reference in their entirety

TECHNICAL FIELD

The present invention relates to a method for use in mobile radio communications network connection, and to a mobile radio communications device, and network device, arranged to achieve such connection.

This application is based upon and claims the benefit of priority from United Kingdom patent application No. 0911118.8, filed Jun. 29, 2009, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND ART

For mobile radio communication devices such as User Equipment (UE) handsets operating in relation to mobile communication networks, various security-related procedures arise at the time of seeking network connection, whether at the time of initial connection or when the UE is required to handover from one network to another. Such handover procedures can involve handovers between different network technologies particularly as communication systems and there underlying technologies evolve.

Security algorithms are generally provided in order to achieve, and maintain, ongoing secure communication between the UEs and the network and it is quite common for the Core Network (CN) to provide the required security algorithm on the basis of the security capabilities of the UE.

Problems and potential limitations have however been found to arise due to the potential for differences in security algorithms arising in particular, subsequent to a change in algorithm due to an upgrade such that one of a UE or a network device is not fully upgraded for use solely with a new algorithm.

The security of ongoing data transfer can then be compromised through the ongoing use of the possibly now out of date, or unsupported and unwanted algorithm.

Various network systems and devices are known relating to security issues and, in particular, security algorithm creation and negotiation such as, for example, found in Chinese Patent Applications CN10124236G, CN101374153, CN101222320 and U.S. patent application US 2006/294575.

While aspects of network security are covered by these earlier applications, none seeks to address the problems now identified and as overcome by the present invention concerning the use of old and potentially unsupported algorithms, and due to the differences in security capabilities that can arise as security algorithms are updated.

DISCLOSURE OF INVENTION

The present invention seeks to provide for a network connection method, and related mobile radio communication and network devices having advantages over known such methods and devices and which, in particular, can offer a high degree of ongoing communication security subsequent to improvements and changes in the security capabilities as represented by the security algorithms.

According to a first aspect of the present invention, there is provided a method for use in a mobile radio communications device network connection procedure and including the step of, at a network, sending to a mobile radio communications device a list of a plurality of security algorithms supported in the network.

It is advantageously found that the employment of such a list of security algorithms within the signal from the network allows for the optimum choice of an appropriate security algorithm, irrespective of whether the mobile radio communications device has been upgraded to support a new security algorithm, and given the combined security capabilities of the mobile radio communications device and the network.

Advantageously, the list of the plurality of security algorithms comprises a prioritized list.

The employment of a prioritized list of security algorithms allows the mobile radio communications device to remain in connected mode whilst achieving an optimum level of security since the actual security algorithm to be used can be negotiated based on the network list of prioritized security algorithms and the mobile radio communication device's knowledge of supported algorithms. Of course, for backward compatibility purposes, the network's most prioritized security algorithms are indicated first in the signalling message, and an additional information element can be included serving to indicate the remaining prioritized security algorithms in decreasing order of priority. Then, if required, the mobile radio communications device can produce more than one security algorithm.

Preferably, the security algorithm selected at the mobile radio communications device, having regard to said list, is subsequently indicated to the network.

In particular, the indication can be included within a connection or handover confirm signal which, for example, can comprise the AS handover confirm signal including the selected AS security algorithm.

Preferably, the “confirm” signal can be unciphered and integrity protected with the selected algorithm.

Further, the selection of the security algorithm can also be included within registration update request signalling which can of course comprise NAS registration update request signalling including a selected NAS security algorithm.

This is particularly so if the mobile radio communications device does not support an old security algorithm.

Further, the registration update request signalling can be integrity protected with the selected security algorithm.

In a further embodiment of the present invention, the method can include the step of, at the mobile radio communications device, signalling a list of supported security algorithms.

Further, a list of unsupported security algorithms can also be included.

Advantageously, registration update requests signalling can be employed to include the list of supported and, if present, unsupported, security algorithms.

This is so particularly if the mobile radio communication device supports the/an old security algorithm.

In this manner, the method can further include the step of selecting, at the network, a security algorithm indicated in the mobile radio communications device signalling as a supported algorithm.

Further, the algorithm selected at the network is then indicated within security mode signalling to the mobile radio communications device.

According to another aspect of the present invention, there is provided a mobile radio communications device arranged for pursuing a network connection procedure and, in particular, arranged to receive signalling from the network providing a list of security algorithms supported by the network.

Preferably, the mobile radio communications device is arranged to receive a prioritized list.

Further, the device is arranged to select one of the listed security algorithms and to provide signalling to indicate which of the security algorithms has been selected.

The device can in particular be arranged to provide an indication of the selected security algorithm within connection, or handover, confirmation signalling.

The device can further be arranged to confirm the selected security algorithm within registration update request signalling.

Further, the device can be arranged to signal to the network a list of supported security algorithms in response to receipt of the list of algorithms provided by the network.

The list can also include a separate indication of unsupported security algorithms.

Preferably, the mobile radio communications device is arranged to signal its list of supported algorithms within registration update request signalling.

According to yet another aspect of the present invention, there is provided a mobile radio communications network device arranged for signalling to a mobile radio communications device a list of supported security algorithms.

Preferably, said list comprises a prioritized list of security algorithms.

The mobile radio communications network device can further be arranged to receive signalling from the mobile radio communications device serving to indicate which of the listed security algorithms has been selected for adoption by the mobile radio communications device.

According to another feature of the invention, the mobile radio communications network device can be arranged to receive signalling from the mobile radio communications device comprising a list of supported and unsupported security algorithms within the mobile radio communications device.

The mobile radio communications device can then be arranged to select a security algorithm indicated as supported by the mobile radio communications device.

The invention proves particularly useful when, for example, network connection of a UE to a EPS network is required, and on the basis of UE EPS security capabilities.

As in any case will be appreciated, the invention provides for ongoing resilience on unsupported EPS security algorithms.

BEST MODE FOR CARRYING OUT THE INVENTION

As discussed further below, the illustrated examples of the present invention are provided in relation to an attempted handover procedure to a EPS network and involving consideration of the relevance and degree of support of the Long Term Evolution (LTE) algorithms at both AS and NAS level.

The invention proves particularly useful when, for example, network connection of a UE to an EPS network is required and on the basis of UE EPS security capabilities. A particular illustrated embodiment of the present invention seeks to overcome the disadvantages as hereinbefore described in relation to the current art and, and as a particular example of such limitations, those found at the time of connection/handover between a UE and a EPS network.

As will be clarified from the following discussion, the invention proves advantageous in overcoming potential security failures that can arise from a potential imbalance between the security algorithms supported by, or employed within, the UE and the network both when, for example, handover is attempted between a suitably upgraded UE and a correspondingly upgraded network, and also a non-upgraded UE and an upgraded network.

In particular, in a situation in which the EPS network does not possess any indication as to the UE EPS security capabilities, for example, if the UE is handed over from a pre-Release 8 network, and a security algorithm is not supported anymore by the UE and the network, the communication between the UE and the network cannot make use of a new security algorithm that might be available at that time.

Also, a new EPS security algorithm can be deployed within the network, and there is provided a method for the network to allow a UE to connect towards the 3GPP LTE access technology even if the UE supports an unwanted (i.e. update no longer supported) security algorithm while the network is already upgraded not to support the unwanted algorithm.

Currently, the connection between the UE and the network is not able to make use of a new EPS security algorithm and so subsequent communication between the UE and the network makes use of alternatives which, from a security point of view can be considered far less robust than the new (upgraded) security algorithm.

Within the context of the present application, a so-called “new” UE or network is considered to be a UE or network that no longer supports an old security algorithm inasmuch as it has been upgraded to support a new security algorithm that is available.

Conversely, an “old” UE or network is a UE or a network that still supports an old security algorithm even though possible updates are available.

Of course, it should be appreciated that such a security algorithm can be related to “integrity protection” or “ciphering” and, as examples, a default set of EPS security algorithms comprises AES based algorithm for encryption such as

SNOW 3G based algorithm and 128-EEA2.

Examples of an AES for integrity protection comprise 128-EIA1 SNOW 3G and 128-EIA2.

It should be appreciated that a so-called old algorithm can form part of the default set of EPS security algorithms (for example from 3GPP Release 8) or can be part of 3GPP Release 8 version.

Whilst, for example, a EPS NAS or AS security algorithm is no longer considered up-to-date insofar as it might have become compromised, then, while a new replacement algorithm is being established within the network has not yet been adopted by the UE, it is a particular advantage of the present invention that the old UE is still able to connect to the network.

Yet further, it is particularly useful for a new UE to be able to use the new EPS security algorithm.

In general therefore, it can prove highly probable that, while a EPS security algorithm is not supported anymore a new EPS security algorithm is about to be adopted and supercede that old one from a time that it is recognised that the older EPS security algorithm is no longer required. There will then be an ever decreasing number of UEs and networks still supporting the “unwanted” EPS security algorithm. As will be appreciated from the following, the present invention advantageously provides for a new network to prioritize the new EPS security algorithm, whilst also maintaining functionality to prevent any problems arising and wherein the network has the capability to instigate a recovery action if it is transpires that the network encounters an old UE requiring connection/handover.

While, at present, when a UE is requested from a pre-Release 8 network which does not have the UE EPS security capabilities, to perform, for example, a handover to the EPS network, the UE will in any case accept the handover which leads to the possibility that data exchange between the UE and the network may use an alternative existing EPS security algorithm which, from a security standpoint, may be considered less robust than the new upgraded algorithms.

Turning now toFIG. 1, there is illustrated a signal timing diagram concerning signalling portions relevant to the present invention and arising between a UE10and a network12, and wherein the UE10comprises a “new” UE insofar as it has been upgraded to support a new security algorithm, and wherein the network12likewise comprises a “new” network also upgraded for the new security algorithm.

It should be appreciated that the signalling arising in relation toFIG. 1relates to a potential handover procedure initiated by a AS handover command message14delivered from the new network12to the new UE10. Insofar as the network had no knowledge of the UE EPS security capabilities of the new UE10, and according to the present invention, a list of possible prioritized security algorithms is included within the AS handover command14wherein each of an AS security container, and a NAS security container, includes such a list of prioritized security algorithms.

Within a AS handover confirmation message16returned from the new UE10to the new network12, there is provided an indication of a selected one of the AS security algorithms listed within the AS handover command14.

Such an AS handover confirmation16is established from the UE10selecting among its supported security algorithms the highest prioritized algorithm according to the list received from the network. Further, the AS handover confirm signal16is unciphered so as to allow the recipient to infer the selected algorithm and the signalling message16is further integrity protected with the actual selected security algorithm.

Subsequent to the AS handover confirm signal16, a NAS registration update request message18is delivered from the new UE10to the new network12and which likewise includes the selected NAS security algorithm. In this manner, the NAS registration update request signalling message18is integrity protected with the selected security algorithm.

Thus, as illustrated, the new network12does not know the UE EPS security capabilities of the new UE10proposes a prioritized list of security algorithms to the UE10one of which is then selected for use by the UE along with conformation of the selection being provided to the network12.

Turning now toFIG. 2, there is provided a similar signalling diagram but this time relating to signalling arising between a new network12and an old user equipment20.

The illustrated signalling again commences with a AS handover command22and, insofar as the network12has no knowledge of the UE EPS security capabilities of the old UE20, it again includes a list of prioritized security algorithms and so includes both an AS and NAS security container including a list of the prioritized security algorithms.

The old UE20then returns its AS handover confirmation signalling message24and, in addition to being unciphered, the message is also not integrity protected insofar as the UE20does not support the new EPS security algorithm indicated by the network.

Subsequently, the old UE20then sends a NAS registration update request signalling message26to the new network12which includes a list of both supported and unsupported, EPS security algorithms.

Upon receipt of the NAS registration update request signalling message26, the new network12initiates a AS security mode command message28which is delivered to the old UE20and which includes an indication of a selected AS security algorithm on the basis of the list of supported and unsupported algorithms contained within the signalling message26.

That is, from the previous unciphered and not integrity protected AS handover confirm message24, the network12triggers the AS security based on the UE's list of supported EPS security algorithms in the NAS registration update request signalling message26, by selecting an EPS security algorithm supported by the UE20and different from the unsupported/unwanted algorithm.

As should be appreciated in particular from the aforementioned illustrated embodiments of the present invention, the invention proves particularly advantageous insofar as it can prevent the loss of data and further allow the UE to remain in connected mode. In particular, the particular security algorithm is negotiated on the basis of the networks list of prioritized security algorithms, and if required, also on the basis of the UE's list of supported algorithms. For the purposes of potential backward compatibility, the networks most prioritized security algorithms are indicated first in the network message, and an additional information element serves to indicate that a main prioritized security algorithms in decreasing order. It can then prove possible for the UE to choose between more than one security algorithm as appropriate.

Turning now toFIG. 3, there is provided a schematic representation of a UE device handset32for use in accordance with the present invention.

The handset32includes standard transceiver functionality34associated with a handset antenna36, and standard processing38and memory40capabilities.

In accordance with the present invention however, the processing38capability of the handset32can include means for receiving a list of prioritized security algorithms from the network and as required, selecting one of those security algorithms, or providing separately a list of supported and unsupported security algorithms for subsequent selection by the network.

Turning lastly toFIG. 4, there is provided a schematic block diagram representing a communications network device42having transceiver functionality44, and processing46and memory48functionality as illustrated.

For such mobile radio communications network device42, the processing46functionality can include means for delivering a list of prioritized security algorithms to a UE device such as the device32as illustrated inFIG. 3and can further be arranged to select one of the security algorithms indicated as supported by the UE.

It will therefore be appreciated that the UE ofFIG. 3and the network device ofFIG. 4can combine functionally within a mobile radio communications network so as to operate in accordance with the method illustrated with reference toFIGS. 1 and 2.

It should therefore be appreciated that the various communication network devices and method of operation provided by the present invention proves advantageous in providing an improved degree of resilience in relation to unsupported EPS security algorithms although it should be appreciated that the invention is not restricted to the details of the specific foregoing embodiments. In particular, any appropriate connection scenario can benefit from the present invention and not merely just the LTE handover procedure illustrated.

Through use of the present invention, ongoing communication between the UE and the network can generally be based upon an appropriately supported security algorithm so as to advantageously maintain connectivity and an appropriate level of security as required.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a network connection method, mobile radio communication and network devices. According to the network connection method, mobile radio communication and network devices, it is possible to offer a high degree of ongoing communication security subsequent to improvements and changes in the security capabilities as represented by the security algorithms.