Method of operating a telecommunication system

Abstract

A method of operating a telecommunications system (100), the telecommunications system comprising: a client device (110) storing a secret and an identifier; and a provisioning (140-1) server that stores the secret and the identifier in association; an intermediate server (130) that communicates with the supply server and the client device; the method comprises the steps of: performing, by the client device, a zero-knowledge proof operation on the secret to output a first solution (220); sending the identifier from the client device to the provisioning server via the intermediate server (230); performing, by the provisioning server, a zero-knowledge attestation operation on a secret associated with the received identifier to output a second solution (250); collecting the first solution and the second solution at the intermediary server, the client device and / or the provisioning server (260); comparing, by the intermediate server, the client device and / or the provisioning server, the first solution and the second solution (270); and in response to determining that the first solution and the second solution are the same, identifying the provisioning server as a trusted provisioning server (280) for configuring the client device.

Description

Technical Field

[0001] The present invention relates to a method of operating a telecommunications system, and more particularly to a method of using zero-knowledge proofs of knowledge to identify a trusted provisioning server for a client device. Background Art

[0002] A networked computing device or client device accessing network services can be remotely configured or provisioned by a remote server accessible via a telecommunications network. It is desirable to perform such provisioning in a secure environment where both the client device and the server are trusted. To this end, the client device should be served only by a trusted provisioning server.

[0003] Given the number of client devices that need to be provisioned, especially with the rise of the "Internet of Things", operating the client devices to access the appropriate trusted provisioning server can be a burdensome task. To help alleviate this burden, zero-touch provisioning has been designed so that the client device can automatically identify and connect to the appropriate trusted provisioning server. For example, to help enable zero-touch provisioning, the client device can typically be pre-configured at the time of manufacture with access details (such as network addresses) for the trusted provisioning server. However, the time period between the manufacture of the client device and its first provisioning can be long, perhaps months if not years. During this period, the network address of the trusted provisioning server may change. As a result, the static network address stored in the client device no longer directly or may not directly point to the trusted provisioning server, thus preventing zero-touch provisioning and thereby hindering the efficient and / or effective operation of the client device.

[0004] It is an object of the present invention to at least mitigate some of the above problems. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a method of operating a telecommunications system, the telecommunications system comprising: a client device that stores a secret and an identifier; and a provisioning server that stores the secret and the identifier in an associated manner; an intermediate server that communicates with the provisioning server and the client device; the method comprising the steps of: performing a zero-knowledge proof operation on the secret by the client device, thereby outputting a first solution; transmitting the identifier from the client device to the provisioning server via the intermediate server; performing a zero-knowledge proof operation on the secret associated with the received identifier by the provisioning server, thereby outputting a second solution; collecting the first solution and the second solution at: the intermediate server; the client device; and / or the provisioning server; comparing the first solution and the second solution by the intermediate server, the client device, and / or the provisioning server; and in response to determining that the first solution and the second solution are the same, identifying the provisioning server as a trusted provisioning server for configuring the client device.

[0006] Preferably, collecting the first solution and the second solution is performed by appropriate communication and / or fetching from memory. Optionally, the communication is encrypted. Preferably, the secret is known only to the client device and the (trusted) provisioning server and may never be transmitted out of the device.

[0007] Preferably, the first solution and the second solution are collected by the client device and / or the provisioning server only through direct communication with the intermediate server. Optionally, the first solution and the second solution are not directly transmitted between the client device and the provisioning server.

[0008] Preferably, the method further comprises the step of the intermediate server transmitting the network address of the client device to the provisioning server, the address being the address of the client device. Optionally, the identifier is the network address of the client device. As used herein, "network address" preferably includes physical, transport, and / or network-level addresses for locating network entities and may include URL, IP, TCP, and / or MAC addresses. The "network address" may also be unique. Preferably, the provisioning server does not have prior knowledge of the network address of the client device.

[0009] Preferably, the method further comprises the step of the intermediate server transmitting the network address of the provisioning server to the client device, the address being the address of the provisioning server. Preferably, the client device does not have prior knowledge of the network address of the provisioning server.

[0010] Preferably, the intermediate server identifies the trusted supply server, and wherein the intermediate server then causes the supply server to supply the client device. Optionally, the intermediate server causes the supply by transmitting information or instructions to the client device and / or the supply server. Preferably, the supply server first identifies the trusted supply server; that is, before the client device and the supply server. Preferably, the intermediate server identifies the supply server as the trusted supply server in response to comparing a first solution and a second solution.

[0011] Preferably, the intermediate server causes the supply by transmitting the client device network address to the supply server, thereby causing the supply server to establish a direct connection with the client device.

[0012] Preferably, the intermediate server causes the supply by transmitting the supply server network address to the client device, thereby causing the client device to establish a direct connection to the supply server.

[0013] Preferably, the intermediate server causes the supply by obtaining data for supplying the client device from the supply server, and the intermediate server transmits the data to the client device.

[0014] Preferably, the client device identifies the supply server as the trusted supply server, and the client device then notifies the intermediate server of the identity of the trusted supply server. Optionally, the client device first identifies the trusted supply server; that is, before the intermediate server and the supply server. Preferably, the client device identifies the supply server as the trusted supply server in response to comparing a first solution and a second solution.

[0015] Preferably, the client device identifies the supply server as the trusted supply server, and wherein the client device then uses the supply server network address to establish a direct connection with the supply server, thereby causing the supply server to supply the client device.

[0016] Preferably, the intermediate server collects the first solution and / or the second solution in response to a request from the client device and / or from the supply server.

[0017] Preferably, the client device and / or the supply server push the first solution and / or the second solution to the intermediate server.

[0018] Preferably, the telecommunications system includes a plurality of supply servers, where only a subset is provided with the secret and the identifier, and where the intermediate server transmits the identifier to all supply servers. Preferably, only the subset is configured to supply the client device. Preferably, the population of supply servers forming the plurality of supply servers is dynamic. Preferably, only the servers in the subset can be identified as trusted supply servers. Optionally, at least one trusted supply server is available.

[0019] Preferably, the client device is preconfigured with the network address of the intermediate server, which is the address of the intermediate server. Preferably, the client device is not preconfigured with the supply server network address or any supply server network address.

[0020] Preferably, the client device is preconfigured to access the intermediate server at initialization. Preferably, the client device performs a zero-knowledge proof function in response to a request from the intermediate server or at initialization.

[0021] Preferably, the telecommunications system further includes an access point, where the intermediate server communicates with the client device via the access point, and where the access point is preconfigured with the network address of the intermediate server to establish an initial connection between the client device and the intermediate server. Preferably, only the access point and not the client device is preconfigured with the intermediate server network address.

[0022] Preferably, the zero-knowledge operation includes the Sigma protocol. Optionally, the client device is an Internet of Things device.

[0023] Preferably, the intermediate server is provided within the core or at the edge of the telecommunications network. Preferably, the supply servers are provided within the data network and outside the core (or the core) of the telecommunications network (or the telecommunications network).

[0024] According to another aspect of the present invention, there is provided a method of operating an intermediate server provided as part of a telecommunications system, the system further including a client device storing a secret and an identifier, and a provisioning server storing the secret and the identifier associatively, the intermediate server being configured to communicate with the provisioning server and the client device, wherein the client device outputs a first solution by performing a zero-knowledge proof operation on the secret, and the method includes the steps of: receiving the identifier from the client device; transmitting the received identifier to the provisioning server, thereby causing the provisioning server to output a second solution by performing a zero-knowledge proof operation on the secret associated with the transmitted identifier; collecting the first solution and the second solution at the intermediate server, the client device, and / or the provisioning server via or by the intermediate server; receiving the result of a comparison of the first solution and the second solution; and in response to the result providing that the first solution and the second solution are the same, identifying the provisioning server as a trusted provisioning server for configuring the client device.

[0025] According to another aspect of the present invention, there is provided a method of operating a provisioning server provided as part of a telecommunications system, the system further including a client device storing a secret and an identifier, and an intermediate server configured to communicate with the provisioning server and the client device, the provisioning server storing the secret and the identifier associatively, and wherein the client device outputs a first solution by performing a zero-knowledge proof operation on the secret, and the method includes the steps of: receiving the identifier from the client device at the provisioning server via the intermediate server; performing, by the provisioning server, a zero-knowledge proof operation on the secret associated with the received identifier, thereby outputting a second solution; collecting the first solution and the second solution at the intermediate server, the client device, and / or the provisioning server; receiving the result of a comparison of the first solution and the second solution; and in response to the result providing that the first solution and the second solution are the same, identifying the provisioning server as a trusted provisioning server for configuring the client device to the provisioning server.

[0026] According to another aspect of the present invention, there is provided a method of operating a client device provided as part of a telecommunications system, the system further including a provisioning server and an intermediate server, the intermediate server being configured to communicate with the provisioning server and the client device, wherein the client device stores a secret and an identifier, and wherein the provisioning server stores the secret and the identifier in association therewith, the method comprising the steps of: performing a zero-knowledge proof operation on the secret by the client device, thereby outputting a first solution; transmitting the identifier from the client device to the intermediate server and for onward transmission from the intermediate server to the provisioning server, thereby causing the provisioning server to perform a zero-knowledge proof operation on the secret associated with the received identifier, and thereby outputting a second solution; collecting the first solution and the second solution at the intermediate server, the client device, and / or the provisioning server; receiving a result of a comparison of the first solution and the second solution; and in response to the result indicating that the first solution and the second solution are the same, identifying the provisioning server to the client device as a trusted provisioning server for configuring the client device.

[0027] According to yet another aspect of the present invention, there is provided a computer-readable carrier medium including a computer program which, when executed by a computer, causes the computer to perform the above method.

[0028] According to another aspect of the present invention, there is provided a telecommunications system, the telecommunications system comprising: a client device, the client device comprising: a first memory for storing a secret and an identifier; and a first processor for performing a zero-knowledge proof operation on the secret to output a first solution; and a first transceiver for transmitting the identifier from the client device; a provisioning server, the provisioning server comprising: a second memory for storing the secret and the identifier in an associated manner; a second transceiver for receiving the identifier; a second processor for identifying the secret associated therewith in association with the received identifier and then performing a zero-knowledge proof operation on the identified secret to output a first solution; an intermediate server, the intermediate server comprising a third transceiver for communicating with the provisioning server and the client device, including transmitting the identifier from the client device to the provisioning server, and for receiving and transmitting the first solution and / or the second solution; a receiver for collecting the first solution and the second solution; a third processor for comparing the collected first solution and second solution, and for identifying the provisioning server as a trusted provisioning server for configuring the client device in response to the processor determining that the first solution and the second solution are the same. Optionally, the receiver is part of the first transceiver, the second transceiver or the third transceiver. Optionally, the third processor is part of the first processor or the second processor, or is part of the intermediate server.

[0029] According to another aspect of the present invention, there is provided a telecommunications system configured to perform any one of the corresponding methods described above.

[0030] According to another aspect of the present invention, there is provided an intermediate server configured to perform any one of the corresponding methods described above.

[0031] According to another aspect of the present invention, there is provided a client device configured to perform any one of the corresponding methods described above.

[0032] According to another aspect of the present invention, there is provided a provisioning server configured to perform any one of the corresponding methods described above.

[0033] The present invention includes any novel aspects described and / or illustrated herein. The present invention also extends to methods and / or apparatuses substantially as described herein and / or as shown with reference to the accompanying drawings. The present invention is also provided as a computer program and / or computer program product for performing any of the methods described herein and / or for implementing any of the apparatus features described herein, and a computer-readable medium having stored thereon a program for performing any of the methods described herein and / or for implementing any of the apparatus features described herein. Features described as implemented in hardware may alternatively be implemented in software, and vice versa.

[0034] Any apparatus feature may also be provided as a corresponding step of a method, and vice versa. As used herein, apparatus-plus-function features may alternatively be expressed in terms of their corresponding structures, such as as a suitably programmed processor.

[0035] Any feature in one aspect of the present invention may be applied in any suitable combination to other aspects of the present invention. Any, some, and / or all features in one aspect may be applied in any suitable combination to any, some, and / or all features in any other aspect. Particular combinations of the various features described and defined in any aspect of the present invention may be implemented and / or provided and / or used independently.

[0036] As used throughout, unless otherwise specified, the word "or" may be interpreted in an exclusive and / or inclusive sense.

[0037] The present invention extends to methods of operating a telecommunications system, methods of operating an intermediate server, methods of operating a client device, methods of operating a provisioning server, a telecommunications system, an intermediate server, a provisioning server, and a client device, as described herein and / or substantially as shown with reference to the accompanying drawings. The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0038] Figure 1 a telecommunications system is shown; and

[0039] Figure 2 a process for operating a telecommunications system is shown. Detailed Description

[0040] Figure 1 A telecommunications system 100 is shown, which includes: a client device 110; an access point 120; an intermediate server 130; and a plurality of provisioning servers 140. The telecommunications systems are interconnected via a telecommunications network (not shown).

[0041] The client device may be in the form of any electronic communication device, in particular: a personal computer (laptop or desktop computer); a mobile telecommunications device; an Internet of Things (IoT) device; and / or a network access point.

[0042] In one example, the access point 120 is a cellular base station (such as a gNodeB), a wireless router, a gateway, an extender, and / or a repeater. In any case, the access point provides access to a telecommunications network.

[0043] Client devices are configured to connect to the access point and thus to the telecommunications network. Communication between them can be used with a wireless or wired interface. In the case of using a wireless interface, the interface forms part of a wide area network or a local area network, such as a cellular network based on 3GPP standards or a Wi-Fi RTM network based on the IEEE 802.11 series of standards. RTM network.

[0044] The intermediate server is configured to identify each of the plurality of supply servers and communicate with them via the telecommunications network. Thus, the intermediate server is a directory of supply servers compiled by a plurality of supply servers registered with the intermediate server to identify themselves as supply servers. The intermediate server can also be accessed by client devices.

[0045] The intermediate server is provided as part of the telecommunications network, such as within the core or at the edge of the network, or within a data network (not shown) outside the telecommunications network but accessible via the telecommunications network. In one example, the intermediate server is owned and / or operated by a telecommunications network operator (such as an Internet service provider).

[0046] The plurality of supply servers is a set of servers configured to supply client devices and is provided as part of a data network. In this example, each supply server is configured to supply a different set of client devices (where only one such set is shown in Figure 1 the figure). Thus, client devices are not available for supply by any and all supply servers. Instead, among the plurality of supply servers, a single trusted supply server that is specifically dedicated and authorized to supply client devices is provided.

[0047] To help securely identify a client device and the corresponding trusted supply server without the client device having prior knowledge of the trusted supply server, the client device and the trusted supply server (but not the remaining supply servers) are preconfigured to store, in association with each other: a common, shared secret (or "pre-known key"); and a unique identifier of the client device. In addition, the client device and the trusted supply server are configured to use the same zero-knowledge proof of knowledge (ZKPK) process, such as according to the Sigma protocol.

[0048] A secret is a data item known only to the client device and the trusted provisioning server (and any other trusted parties). To help ensure confidentiality, the secret is intended not to be transmitted away from the client device and the trusted provisioning server. The data item is available in the form of a password, passcode, passphrase, number, and / or array of numbers.

[0049] The unique identifier of the client device can be a network address, international mobile subscriber identity, and / or international mobile equipment identity. The unique identifier can be a public, non-secret identifier, and the secret cannot be publicly derived from the unique identifier. The identifier is unique among all identifiers on all provisioning servers, or only unique among all identifiers stored in the trusted provisioning server.

[0050] With the above characteristics, and according to the process described below, the intermediate server can be used as a static point for the client device to securely discover and then access the trusted provisioning server, without the client device having to be pre-configured with explicit knowledge of the trusted provisioning server. Since the intermediate server can be used to perform the matching role between multiple different client devices and the trusted provisioning server, the intermediate server acts as a general central agent.

[0051] Figure 2 An exemplary process 200 is shown for operating a telecommunications system to securely identify the trusted provisioning server to the client device and / or vice versa, without the client device having prior knowledge of the identity of the trusted provisioning server.

[0052] In a first step 210, the client device and the trusted provisioning server are provided with the same, shared, secret, and unique identifier of the client device. In one example, the client device creates or is provided with the secret and / or unique identifier at the point of manufacture, which is then shared with the trusted provisioning server. The shared secret can be generated based on a hardware or software trust root.

[0053] In the next step 220, the client device performs a ZKPK operation on the secret to output a first solution. The first solution can be public and non-secret, and can only be cryptographically derived from the secret.

[0054] In the next step 230, the client device transmits the first solution and the unique identifier associated with each other to the intermediate server. For this purpose, the client device is pre-configured with the network address of the intermediate server, such as a URL. The client device that has connected to the access point uses this network address to establish a connection with the intermediate server. In one example, the access point and / or the telecommunications network is configured to resolve the network address to the intermediate server.

[0055] In the next step 240, the intermediate server polls the supply servers by transmitting the unique identifier received from the client device to each of the multiple supply servers (including the yet unknown trusted supply servers).

[0056] In the next step 250, in response to receiving the unique identifier, each supply server performs a lookup operation to identify the secret associated with the received unique identifier. In the case where the supply server stores the associated secret for the received unique identifier, each such supply server performs a ZKPK operation on the secret, thus all outputting a second solution, and the total multiple second solutions form a set formed by (at least one) second solution.

[0057] In the next step 260, each supply server that outputs the second solution transmits the solution along with the identifier of the supply server (also referred to as the "supply server identifier" or "supply server network address") to the intermediate server, such that the intermediate server compiles the set of second solutions and the associated identities of the supply servers from which each second solution originated.

[0058] In the next step 270, the intermediate server then compares each second solution within the set of second solutions with the first solution. In the case where the intermediate server identifies a supply server that has provided a second solution identical to the first solution, the intermediate server identifies the supply server as a trusted supply server for the client device. In this way, the intermediate server acts to verify that both the client device and the trusted supply server have knowledge of the secret (without obtaining knowledge of the secret in the middle), and thus these two entities can trust each other. Identifying the supply server as trustworthy means authorizing the client device to communicate with and be configured by the server.

[0059] It should be understood that any supply server that does not respond with a second solution (e.g., because there is no secret associated with the received unique identifier) cannot be identified as a trusted supply server. Similarly, any supply server that responds with a second solution that does not match the first solution (e.g., because a different secret and / or ZKPK operation is used for the client device, such as because the unique identifier is not universally unique) is also not identified as a trusted supply server.

[0060] Therefore, in the next step 280, the intermediate server identifies the trusted supply server to the client device and / or vice versa. To this end, the intermediate server transmits the network address of the client device and / or the trusted supply server to the other party. In this way, the client device and the trusted supply server are now available to establish a direct connection between the two to allow for secure supply to the client device.

[0061] In a final step 290, the client device and the trusted provisioning server establish a direct network connection via a telecommunications network, and the trusted provisioning server performs provisioning of the client device.

[0062] Such provisioning can be used to include transferring data, including software and / or firmware updates, and configuring operating parameters of the client device such as security and / or network parameters.

[0063] Alternative and Modification Examples

[0064] In an alternative, the client device is configured to first identify the trusted provisioning server. To this end, a set of second solutions and corresponding provisioning server identifiers are transmitted to the client device in association, and collected by the client device. The client device then compares the first solution and the second solutions to identify matching pairs of the first and second solutions, and thereby identifies the trusted provisioning server. Then, according to step 290, the client device identifies the trusted provisioning server to the intermediate server (using the associated identifier) such that the intermediate server can communicate with the trusted provisioning server to establish a connection with the client device.

[0065] In an alternative, the identification of the trusted provisioning server is performed by a plurality of provisioning servers by transmitting the first solution from the client device to each provisioning server via the intermediate server. Each provisioning server then compares the first solution with second solutions appropriately generated by the provisioning server performing the comparison. Then, according to step 290, the trusted provisioning server can be used to identify itself to the intermediate server for the client device (identified according to the unique identifier of the client device that has been provided to each provisioning server to generate the second solutions) such that the intermediate server can communicate with the trusted provisioning server to establish a connection with the client device.

[0066] In an alternative, the provisioning server identifier and / or the unique identifier of the client device is the network address of the provisioning server and / or the client device. Thus, when identified, the client device and / or the trusted provisioning server can be directly used to establish a connection with the trusted provisioning server and / or the client device, respectively.

[0067] In an alternative, in the case where the intermediate server first identifies the trusted provisioning server, the knowledge of the identity is retained only by the intermediate server. To perform provisioning of the client device, the intermediate server instructs the trusted provisioning server to transmit data for provisioning the client device to the intermediate server, and then the intermediate server transmits the data to the client device. In this way, the intermediate server also acts as a relay or proxy for providing the client device.

[0068] While Figure 1 and Figure 2It is shown and described with reference to only one of a plurality of client devices, but it should be understood that the telecommunications system 100 can be used to include a plurality of client devices, each client device being configured in a manner corresponding to but different from the client device (i.e., having a secret, unique identifier, the ability to perform ZKPK operations, knowledge of the intermediate server, and having an associated trusted provisioning server). Accordingly, the intermediate server is configured to have a many-to-many relationship between the client devices and the provisioning server.

[0069] In an alternative, the client device is a group formed by at least two client devices, each client device having the same unique identifier and secret, and thus each member of the group having the same trusted provisioning server. When a trusted provisioning server is identified for one of the client devices in the group according to process 200 or the alternative, as the case may be, then when the first solution is submitted and it is determined that the first solution matches the previously provided second solution, the intermediate server may identify the same trusted provisioning server for the remaining client devices in the group, thereby allowing steps 240 to 260 to be bypassed.

[0070] In one example, the intermediate server includes a group formed by at least two associated servers and may be in the form of a distributed computing system.

[0071] In an alternative, the intermediate server is configured to sequentially poll individuals or subsets of the provisioning servers, thereby repeating steps 240 to 270 for each polled provisioning server until a trusted provisioning server is identified.

[0072] Although Figure 1 and Figure 2 only three provisioning servers are shown and described, one of which is the trusted provisioning server for the client device, it should be understood that there can be at least one provisioning server and at least one trusted provisioning server. This includes the possibility of there being only one provisioning server which is also the trusted provisioning server, or there being multiple provisioning servers, among which there are multiple trusted provisioning servers for the client device.

[0073] Each feature disclosed herein and (where appropriate) as part of the claims and the drawings can be provided independently or in any suitable combination.

[0074] Any reference signs appearing in the claims are for illustrative purposes only and shall not limit the scope of the claims.

Claims

1. A method of operating a telecommunications system, the telecommunications system comprising: a client device that stores a secret and an identifier; and a provisioning server that stores the secret and the identifier in an associated manner; an intermediate server that communicates with the provisioning server and the client device; the method comprising the steps of: performing a zero-knowledge proof operation on the secret by the client device, thereby outputting a first solution; transmitting the identifier from the client device to the provisioning server via the intermediate server; performing a zero-knowledge proof operation on the secret associated with the received identifier by the provisioning server, thereby outputting a second solution; collecting the first solution and the second solution at: the intermediate server; the client device; and / or the provisioning server; comparing the first solution and the second solution by the intermediate server, the client device, and / or the provisioning server; and in response to determining that the first solution and the second solution are the same, identifying the provisioning server as a trusted provisioning server for configuring the client device.

2. The method according to claim 1, wherein the first solution and the second solution are collected by the client device and / or the provisioning server only through direct communication with the intermediate server.

3. The method according to claim 1 or 2, the method further comprising the step of the intermediate server transmitting the client device network address to the provisioning server, the address being the address of the client device.

4. The method according to any one of the preceding claims, the method further comprising the step of the intermediate server transmitting the provisioning server network address to the client device, the address being the address of the provisioning server.

5. The method according to any one of the preceding claims, wherein the intermediate server identifies the trusted provisioning server, and wherein the intermediate server subsequently causes the client device to be provisioned by the provisioning server.

6. The method according to claim 5 when dependent on claim 3, wherein the intermediate server causes the provisioning by transmitting the client device network address to the provisioning server, thereby causing the provisioning server to establish a direct connection with the client device.

7. The method according to claim 5 or 6 when dependent on claim 4, wherein the intermediate server causes the provisioning by transmitting the provisioning server network address to the client device, thereby causing the client device to establish a direct connection to the provisioning server.

8. The method according to claim 5, wherein the intermediate server causes the provisioning by obtaining data for provisioning the client device from the provisioning server, and the intermediate server transmits the data to the client device.

9. The method according to any one of the preceding claims, wherein The client device identifies the supply server as the trusted supply server, and the client device then notifies the intermediate server of the identity of the trusted supply server.

10. The method according to any one of the preceding claims, when dependent on claim 4, wherein, The client device identifies the supply server as the trusted supply server, and wherein the client device then uses the supply server network address to establish a direct connection with the supply server, thereby causing the supply server to supply the client device.

11. A method of operating an intermediate server provided as part of a telecommunications system, the system further including a client device storing a secret and an identifier, and a supply server storing the secret and the identifier associatively, the intermediate server being configured to communicate with the supply server and the client device, wherein, The client device outputs a first solution by performing a zero-knowledge proof operation on the secret, and the method includes the following steps: Receiving the identifier from the client device; Transmitting the received identifier to the supply server, thereby causing the supply server to output a second solution by performing a zero-knowledge proof operation on the secret associated with the transmitted identifier; Collecting the first solution and the second solution at the intermediate server, the client device, and / or the supply server via or by the intermediate server; Receiving the result of the comparison of the first solution and the second solution; and In response to the result indicating that the first solution and the second solution are the same, identifying the supply server as the trusted supply server for configuring the client device.

12. A method of operating a supply server provided as part of a telecommunications system, the system further including a client device storing a secret and an identifier, and an intermediate server configured to communicate with the supply server and the client device, the supply server storing the secret and the identifier associatively, and wherein, The client device outputs a first solution by performing a zero-knowledge proof operation on the secret, and the method includes the following steps: Receiving the identifier from the client device at the supply server via the intermediate server; Performing a zero-knowledge proof operation on the secret associated with the received identifier by the supply server, thereby outputting a second solution; Collecting the first solution and the second solution at the intermediate server, the client device, and / or the supply server; Receiving the result of the comparison of the first solution and the second solution; and In response to the result indicating that the first solution and the second solution are the same, identifying the supply server as the trusted supply server for configuring the client device to the supply server.

13. A method of operating a client device provided as part of a telecommunications system, the system further including a supply server and an intermediate server, the intermediate server being configured to communicate with the supply server and the client device, wherein, The client device stores a secret and an identifier, and wherein the supply server stores the secret and the identifier in association therewith, the method comprising the steps of: Performing a zero-knowledge proof operation on the secret by the client device, thereby outputting a first solution; Transmitting the identifier from the client device to the intermediate server and for further transmission from the intermediate server to the supply server, thereby causing the supply server to perform a zero-knowledge proof operation on the secret associated with the received identifier, and thereby outputting a second solution; Collecting the first solution and the second solution at the intermediate server, the client device, and / or the supply server; Receiving the result of the comparison of the first solution and the second solution; and In response to the result indicating that the first solution and the second solution are the same, identifying the supply server to the client device as a trusted supply server for configuring the client device.

14. A computer-readable carrier medium comprising a computer program which, when executed by a computer, causes the computer to perform the steps according to any one of the preceding claims.

15. A telecommunications system, the telecommunications system comprising: A client device, the client device comprising: A first memory for storing a secret and an identifier; and A first processor for performing a zero-knowledge proof operation on the secret, thereby outputting a first solution; and A first transceiver for transmitting the identifier from the client device; A supply server, the supply server comprising: A second memory for storing the secret and the identifier in association therewith; A second transceiver for receiving the identifier; A second processor for identifying the secret associated therewith in association with the received identifier and then performing a zero-knowledge proof operation on the identified secret, thereby outputting a first solution; An intermediate server, the intermediate server comprising A third transceiver for communicating with the supply server and the client device, including transmitting the identifier from the client device to the supply server, and for receiving and transmitting the first solution and / or the second solution; A receiver for collecting the first solution and the second solution; A third processor for comparing the collected first solution and second solution, and for identifying the supply server as a trusted supply server for configuring the client device in response to the third processor determining that the first solution and the second solution are the same.

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