Patent Description:
Traffic managed User Equipment (UE) typically connects to a remote endpoint via a tunnel as for example by Virtual Private Network (VPN) technology. The remote endpoint can be a server of a provider that is located in the network. The remote endpoint is responsible to request and/or deliver the service on behalf of the user equipment as depicted in <FIG> for illustration purposes.

Such communication scenarios are common for securing, shaping and monitoring data traffic, protecting the UE and its associated services and managing the data traffic. Managing the data traffic becomes more sophisticated in multi-connectivity environments, in particular when the user equipment is connected in a hybrid communication scenario with more than one communication access or communication link at a time. For example, the user equipment can be connected via a cellular and Wi-Fi communication link to the network.

Encryption and especially encryption of data traffic transmitted via tunnels has become a key requirement in a compute cloud environment, wherein all the communications between assets are required to be encrypted. An example is IPSec tunneling to connect system components. Often, setting up an encrypted tunnel between different network entities, virtual machines (VMs) or similar entities is to ensure that communications between hosts are sufficiently secure so that confidential information (e.g., associated with a particular tenant) will not be leaked. A known straightforward implementation that addresses the latter requirement is to simply setup an encrypted tunnel with a maximum security level between the network entities, and then use this tunnel for all of the communications. While this approach is commonly used, it can lead to resource over-utilization, especially in the case where applications/protocols running on the network entities, in particular running on the UE and/or the server, and already provide encrypted data. In particular, and because the underlying data itself is already encrypted, setting up and maintaining a further encrypted channel (namely, the IPSec tunnel through which the originally-encrypted data can then travel) leads to a waste of computational and memory resources.

To address this "waste" of computational and memory resources, <CIT> teaches a method of context-based adaptive encryption between entities that transfer their data within the network over a communication link of a single access technology. A data packet that is to be transmitted via the single communication link is being analyzed with respect to its content and it is determined if the information in the data packet can be transported between the entities according to certain security policies. Depending on the security demand, the data packet can be transmitted via an encryption layer over a first channel or via an unencrypted layer over a second channel, wherein that second channel saves computational and memory resources.

<CIT> discloses a method wherein a network node (e.g. eNB) configures a user equipment to use an aggregation of radio technologies. At least one radio bearer is established between the user equipment and the network node and is routed over an access point of an alternate wireless network. The method includes determining whether trustworthy security is provided by the access point of the alternate wireless network and instructing the user equipment to turn off ciphering based on the determining. The ciphering is turned off for the at least one radio bearer between the user equipment and the network node.

<CIT> discloses eliminating redundant encryption at the PDCP layer of LWA traffic sent on WLAN -which is already encrypted in LWA either using the encryption keys defined in the new procedure defined by 3GPP or using legacy encryption protocols- in order to reduce the UE processing time and power consumption and which results in significant improvement in UE battery life or lower complexity in the UE which in turn provides power and cost savings.

An almost standardized multi-connectivity architecture, which makes use of the above described VPN technology is 3GPP ATSSS as described in "<NPL>". ATSSS manages simultaneous connectivity for UEs in hybrid communication scenarios like over cellular (3GPP access) and non-cellular access (e.g. Wi-Fi). <FIG> shows schematically such an ATSSS process, respectively the network protocol stack for passing through the Wi-Fi in <FIG>, highlighting the IPsec tunnel in use. In addition to an ATSSS approach, <FIG> describes a principal architecture of an UE that manages the traffic on the basis of a OTT multi-connectivity provider. The approach of <FIG> differs from ATSSS in respect that the access network operator can leverage tunnel methods for each individual access.

In the above described scenarios, tunnels that are used for single path or multipath are usually encrypted for several reasons, e.g. protecting traffic when passing potential untrusted networks.

In a broader context also SOCKS can be seen as a tunnel from a technical viewpoint, which is widely used in Multipath-TCP, MPTCP, environments as described in "https://www. net/mtcp-deployment-options/. " These methods can be encrypted by additional components, for example encryption layers, since SOCKS does not provide encryption by itself.

It is an object of the invention to provide methods and techniques to further reduce computational and memory resources associated with the encrypted data transfer in networks, especially in hybrid wireless networks.

According to a first aspect of the invention, the invention provides a method for ensuring secure communication, in particular wireless communication, of a User Equipment, UE, in a communication system, wherein the communication system comprises
an User Equipment and a server, in particular a server of a network provider, configured to communicate data of a data traffic with each other over a network via a first communication link of a first access technology and a second communication link of a second access technology, possible access technologies of the so-called hybrid communication network can be: Ethernet (<NUM>), Wi-Fi (<NUM> a/b/g), <NUM>, LTE, and/or <NUM> standards;.

The above mentioned OTT technique generally uses tunneling. In that case, tunneling will be accepted and the security level is being adjusted only with respect to the encryption level, which can in principle be subdivided in multiple sub-levels. In a similar way, ATSSS generally uses one of its communication links as a tunnel.

In an embodiment, the algorithm analyzes the data for transmission and determines a security demand level of the data. The analyzed data can be the data that is used by an application running on the UE and/or the server. Typically, the data is transmitted in pieces of data, the so-called data packets, wherein it is possible to analyze each data packet because each of these data packet can require a different security demand level due to different content.

This provides the advantage, that the algorithm gains knowledge about how critical certain data packets are and if there are differences concerning the required security demand level between the individual data packets. For example, it is possible to define three different security demand levels: high, medium and low. Of course, the invention is not limited to three different security demand levels so that it is in principle possible to define any number of security demand levels. If the analysis yields that all data packets have for example a low security demand level, it might even be possible that no additional tunnel encryption is required at all.

In an embodiment, the data is analyzed with respect to DPI, protocol information and/or destination of data packets. The algorithm, in particular a packet parser unit, analyzes one or more attributes, e.g., protocol type, application type, current encryption strength, content payload, etc., associated with a data packet transmission to determine to which level tunnel encryption is even required. The evaluation can include a deep packet inspection (DPI), especially when the information at the network layer (e.g., IP address, port number, etc.) is not sufficient to determine if the payload in the packet needs to be further encrypted. Based on the result of the analysis, data packets are dispatched to an encryption process that can be implemented in the algorithm.

A simple example is when the payload contains a credit card number. Packet content analysis typically leverage the Deep Packet Inspection (DPI) capabilities that are available in the device in which the functionality is implemented. DPI may also be required when the information at the network layer (e.g., IP address, port number, etc.) is not sufficient to determine if the payload in the packet needs encryption. Thus, preferably the payload content analysis uses DPI during the packet parsing. The payload content analysis using DPI inspection may identify other user attributes, such as user identity, that are then evaluated for compliance with a particular security policy. Of course, these are merely representative examples.

In an embodiment different data packets of the data require different security demand levels.

This provides the advantage, that the security level can be set to level that satisfies of all data packets. This also provides an option to decide if certain data packets shall not be transmitted at all due to their security demand is not being fulfilled.

Preferably, the security demand level of the data packets serves as a second input parameter to the algorithm for the calculation of the encryption security levels.

This provides the advantage, that the security levels can be adjusted as to meet the requirements of the individual security demands of each data packet.

In an embodiment, a multipath scheduler schedules data packets of the data traffic to the first communication link or the second communication link. The multipath scheduler that can be implemented in server or in the UE is a functional unit that distributes data packets to different communication links by applying certain rules. The policy of the rules can be, that the multipath scheduler can distribute the data to reach maximal data throughput on the communication network. In principle, this policy can consider security issues.

The multipath scheduler can receive the information about the type of trustiness and/or the security demand level of the data. By receiving the information about the type of trustiness and/or the security demand level of the data, this information can serve as input to the rules which are applied by the multipath scheduler.

Preferentially the multipath scheduler schedules the data packets of the data traffic to the first communication link or the second communication link based on the respective security demand level of the data packets and/or the type of trustiness of the data. Each data packet can be signed to one of the communication links and each of those data packets can be encrypted with its individual security level.

This provides the advantage of a maximal flexibility in and distributing the data packets to the first communication link or to the second communication link in order to find the optimal trade-off between security and saving of computational resources. For example, very critical data - with a high security demand level - can be distributed to the communication link that has a high level of trustiness and can be tunneled and/or encrypted with a high encryption security level; and very uncritical data - with low security demand level - can be distributed to the communication link that has a low level of trustiness and can be encrypted with a low encryption security level.

In an embodiment, information about the type of trustiness is stored in a network entity, gained from user feedback, gained from Wi-Fi specifications and/or gained from location information. The network entity can be a UE or a server.

This provides the advantage, that the server can also serve as a trusted authority or that information about the type of trustiness can be assessed by different means. For example, if there is no information about the type of trustiness start in a trusted authority, it is possible that the user defines such a type of trustiness. This could be the case, if the user checks in into the hotel and he has full trust in the local Wi-Fi of the hotel from the Wi-Fi specifications the name type of security (WPAx,. ) can be assessed. Is also possible to determine which Wi-Fi hotspot is available at a distinct location by using GPS, cell-id, Wi-Fi triangulation and/or SSIDs.

Advantageously, a control plane is established on the communication link to transmit the information about the type of trustiness from the Server to the UE.

In contrast to the user plane, the control plane is to be understood as a communication link in which no critical data concerning the user is being transmitted. It follows, that it is no big security issue if data of this control plane is transmitted without high security measures. If the UE is to set the security level for the user plane, it needs to know about the information about the type of trustiness. If the server uses the control plane to transfer those data this has the benefit, that no critical user data is transferred along with the information about the type of trustiness. The UE then has the necessary data to decide on an appropriate security level of the user plane.

In an embodiment, the information about the type of trustiness is transmitted via a cellular network from the Server to the UE.

This provides the advantage, that the information about the type of trustiness is transmitted via an alternative channel independent from foreign Wi-Fi hotspots or the like, so that the information about the type of trustiness cannot be manipulated while it passes through the foreign Wi-Fi hotspot.

As a second aspect, the invention provides a communication system for ensuring secure wireless communication of a User Equipment, UE, wherein the communication system is configured to perform the steps according to a method of claims described above, wherein the communication system comprises.

This provides analogous advantages as described in conjunction with the inventive method.

In an embodiment, the User Equipment and/or the server comprise a multipath scheduler configured to distribute the data traffic between the first and the second communication link.

This provides the advantage that each of the devices can efficiently distribute the data traffic or that the efficiency is even improved if both devices distribute data traffic.

According to a third aspect, the invention relates to a method for ensuring secure communication of a network entity, in particular a User Equipment or a server of a network provider, with another network entity over a network, wherein the method comprises the steps of:.

This provides the advantage that a generic network entity, in particular the user equipment or the server, can perform the inventive steps to yield the advantages discussed above. It follows that a user could decide to buy user equipment, for example a smartphone, that is configured to perform the steps described above so that the gates and optimal trade-off between security and battery lifetime when using his smart phone.

According to fourth aspect, the invention relates to a network entity in particular a User Equipment or a server of a network provider, for ensuring secure communication of a network entity with another network entity over a network entity configured to perform the steps according to a method described above, wherein the network entity comprises:.

According to a fifth aspect, the invention relates to a computer program product running on a network entity and adapted to perform the method described above.

<FIG> shows a schematic architecture for an Over-the-top Multi-Connectivity provider according to the invention. The user equipment <NUM> has a computing unit <NUM> to execute codes implemented in an algorithm on the computing unit <NUM>. The user equipment <NUM> has a network interface <NUM> configured to enable multi-connectivity of the UE <NUM> over different communication links <NUM>, <NUM>, in particular communication links <NUM>, <NUM> with different communication standards in a hybrid communication scenario, like Wi-Fi, LTE, and/or <NUM> techniques. Each of the communication links <NUM>, <NUM> can be provided by a different Internet access provider or by one single Internet access provider. In principle, the number of communication links <NUM>, <NUM> is not limited. The communication links <NUM>, <NUM> are implemented as tunneled communication links <NUM>, <NUM>. The tunneled communication links <NUM>, <NUM> combine at a network entity that is closer to the core network. However, the communication links <NUM>, <NUM> can also be implemented as encrypted tunneled communication links <NUM>, <NUM>, encrypted communication links <NUM>, <NUM> or in any combination of those techniques. In <FIG> this network entity is realized by means of a multi-connectivity provider <NUM> that can provide authentication <NUM>, authorization <NUM>, accounting <NUM> and or multi-connectivity traffic management <NUM>. All of these functionalities of the multi-connectivity provider <NUM> can be implemented on a server <NUM> that is associated with the multi-connectivity provider <NUM>. A further communication <NUM> connects the multi-connectivity provider <NUM> to the Internet <NUM>.

The invention proposes a technology to avoid or reduce the consuming of resources when applying terminal encryption in multi-access scenarios. As a general rule, encryption compared to non-encrypted tunnel/access leads to increased energy consumption and the propagation of traffic is limited, too.

The technique of tunneling data traffic to redirect data through a traffic management remote point is important to ensure security and is therefore not put into question. However, depending on the on the type of trustiness, which basically means the level of trustiness, of the communication links, accesses, networks that need to be passed and/or security demand level of services/applications, different encryption levels can be applied to the tunnel. Furthermore, these encryption levels can be adjusted during communication which yields to a dynamically adjusted encryption level of the respective communication links.

An example is the application of an encryption algorithms, which are "weaker" encrypted compared to a properly secured tunnel but provide faster transmission and lower energy consumption. In other words, this is called an encryption having the lower encrypting level. Such a lower encrypting level can be applied if the data of the application is not that critical and/or if the communication link has a high level of trustiness. In the case of IPsec "NULL encryption" as defined in "<NPL>" it is an option to us a tunnel technology without encryption like IP-in-IP in "<NPL>".

Two main solutions are proposed to overcome resource consuming encrypted tunnel in the traffic managed UE scenario by.

Both solution require input which trustiness level or levels are required, the input is given over to an algorithm implemented on the computing unit <NUM> and/or the server <NUM> as parameter. Based on these parameters, the algorithm calculates the adaptive tunnel encryption level. This input can be provided by the operator of the traffic management solution unit, the UE <NUM> itself, or by Service/Application requirements.

In addition, the second solution requires a switch implemented in the UE <NUM> and/or the server <NUM> to steer different type of data traffic, in particular individual data packets, with different required security demand levels into the respective tunnel with the appropriate encryption level.

The first solution is considered to be the simpler one from an administration perspective but can only provide one uniform security level of the tunneled communication links <NUM>, <NUM> at a time, which can be based on the highest security level demand. Basically, this uniform security level is set by the data packet that has the highest security demand level. Nevertheless, it is possible that the encryption security level is lowered if following data packets have lower security level demands.

The second solution can simultaneously provide different security encryption level of the tunneled communication links <NUM>, <NUM> and hence offers finer resolution of security level demands and provides a better resource footprint. Resource consumption by tunnel encryption only takes place when the tunnel is used for transmission. An idle/unused encrypted tunnel does not require resources in this context. Therefore, the UE <NUM> might set up a first encrypted tunnel <NUM> with the highest possible encryption level and a second encrypted tunnel <NUM> with the lowest possible encryption level and decide before the transmission of each individual data packet to which of the two tunnels <NUM>, <NUM> the data packet will be distributed by means of the switch, which is typically represented by a multipath scheduler. If the algorithm on the computing unit <NUM> decides that the data packet has a low security demand level, then this data packet can be scheduled to the second encrypted tunnel <NUM>. This leads to a minimal resource consumption while at the same time the first encrypted tunnel <NUM> is still established and can be used if it would be needed for following data packets.

In the following different examples of technical implementation are described:.

A smartphone <NUM> connects to a Wi-Fi access, that can be represented for example by the communication link <NUM>. The smartphone <NUM> receives the information that it can have trust in the communication link <NUM>. This information about the type of trustiness can be given to the smartphone <NUM> by a network operator <NUM> or other trusted entities associated to the network. Especially if the operator of the excess and the traffic management operator are identical or share a relationship, they can valid give statements about the level of trustiness. It follows that for both the first and the second solution, the tunnel encryption can be switched off or set to the lowest encryption level.

A banking application is used on the smartphone <NUM> by the traffic management solution over an untrusted access. The banking application implements its own secure communication. The information about the security measures implemented by the banking software can be given as input to the algorithm so that it can decide how to adjust the tunnel encryption level.

HTTP traffic is unsecured by default. For untrusted traffic it makes sense to generally protect such a traffic environment.

A great advantage is that the invention also considers "the type" of underlying access. In other word, the trustiness of the communication links <NUM>,<NUM>. This results in an extra degree of freedom when determining which level of tunnel encryption is required.

If a UE <NUM> is connected simultaneously to a cellular and Wi-Fi access by the respective communication links <NUM>, <NUM>, whereas the cellular access is defined as a trusted access and the Wi-Fi as an untrusted access. Giving these parameters as input to the algorithm, this could result in a decision to establish no tunnel encryption over the cellular communication link and establish two tunneled communication links over Wi-Fi access, whereas one of the Wi-Fi communication links is being operated with and the other without tunneled encryption. A dedicated logic is required with in the UE <NUM> and/or the server <NUM> to run such tunneled communication links <NUM>, <NUM>. In solution <NUM>, the packet switch, e.g. the multipath scheduler, implemented in the UE <NUM> and/or the server <NUM> can decide to send already secured traffic through the trusted cellular communication link without additional encryption because it is considered to be secure. As another option, the packets which can decide to use an encrypted tunnel over the Wi-Fi communication links.

Preferably, the multipath scheduler, e.g. a MPTCP scheduler or MPDCCP scheduler, has knowledge about the individual access trustiness level of the communication links and/or the security demand levels of the data packets. The security demand level of the data packets can be provided by DPI, protocol information, Destination etc. depending on cost metrics (monetary, energy,.

The invention result in cellular usage, which does not require additional computation overhead leading to higher energy consumption and lower propagation speed. However, when monetary costs outweigh, the encrypted Wi-Fi tunnel might be preferred.

The same scenario could also lead to the situation that no encrypted tunnel over the Wi-Fi will be established, since it is known that the cellular access can securely take care on unprotected data.

Another scenario considers both accesses as untrusted which leads to the establishment of an encrypted tunnel and an unencrypted tunnel per access. The packet switch of solution <NUM> can select between four logical links, whereas two are encrypted and two non-encrypted.

In case both accesses are trusted no encrypted tunnel is needed at all.

<FIG> shows an inventive algorithm implemented on a network entity, e.g. the smartphone <NUM> or the server <NUM>:.

Claim 1:
A method for ensuring secure wireless communication of a User Equipment, UE, in a communication system, wherein the communication system comprises
the User Equipment and a server configured to communicate data of a data traffic with each other over a network via a first communication link of a first access technology and a second communication link of a second access technology;
the method comprises the steps of:
Retrieving information about a type of trustiness of the first communication link of the first access technology and about a type of trustiness of the second communication link of the second access technology;
Providing the information about the type of trustiness of the first communication link and about the type of trustiness of the second communication link as a first input parameter to an algorithm implemented on a computing unit of the UE and/or the server, wherein the algorithm is configured to calculate security levels,
wherein as a first option: the algorithm sets-up a uniform dynamic security level of the first communication link and the second communication link based on the information about the type of trustiness of the communication links, wherein the dynamic security level can be adjusted during the course of communication; or as a second option: the algorithm sets-up a first security level of the first communication link and a second encryption security level of the second communication link based on the information about the type of trustiness of the communication links, wherein the first security level is different from the second security level.