Method and mobile device for providing time reading

Abstract

A method for providing a time read is provided. The method is performed by a mobile device (2) comprising a secure element (1) comprising a real-time clock (7). The method comprises: synchronizing (40), by the secure element, the real-time clock (7) with the time server (3); operating (42) the real-time clock (7) in the secure element (1); receiving (44), by the secure element (1), a current time request (30) from the time reader (6) via the mobile device (2); generating (46), by the secure element (1), a response comprising a current time read from the real-time clock (7) and cryptographic verification data; and sending (48), by the secure element (1), the response (32) to the time reader (6) via the mobile device (2).

Description

Technical Field

[0001] The present disclosure relates to the field of time reading, and more particularly to methods and mobile devices for providing time reading to a time reader. Background Art

[0002] Manufacturing digital devices that can tell the correct time is difficult and extremely complex. Manufacturing such devices that can tell time in a digitally trustworthy manner is even more difficult.

[0003] Time itself is a complex topic. There are several time scales. One follows the rotation of the Earth, so a particular time of day corresponds to a particular angle of rotation of the Earth. One time scale is used in GPS (Global Positioning System) and is used for scientific measurements. However, for everyday life, the UTC (Coordinated Universal Time) time standard is typically used as the basis for synchronizing clocks. UTC is based on TAI (International Atomic Time), which in turn is based on the time of approximately 500 atomic clocks, many of which use the SI (International System of Units) definition of the second to keep time (cesium atomic clocks). The French organization BIPM (Bureau International des Poids et Mesures) publishes UTC time based on a comprehensive trade-off of the time synchronization of these atomic clocks.

[0004] In practice, to synchronize online computer systems, so-called NTP (Network Time Protocol) servers on the Internet are used to distribute UTC time. Examples of some NTP servers can be found at time.google.com, ntp.se, and time.nist.gov. Thus, servers connected to the Internet can use the UTC time standard by periodically synchronizing their internal clocks with a trustworthy NTP server on the Internet.

[0005] Trustworthy clocks are important for digital security. Generally, when creating a digital authorization, a best practice is to set a time limit on its validity - i.e., an expiration time. Thus, an access monitor (software that makes an authorization access or denial decision) needs to compare the expiration time of the authorization with the current time. However, this relies on the access monitor being online to synchronize its time with a trustworthy NTP server. When the access monitor is an offline device, there is no good solution in the prior art for obtaining a trustworthy time reading. In some cases, the access monitor is completely powered off most of the time to save energy. How can the access monitor reliably tell the time when it needs to make an access decision? The access monitor does not have a continuous energy source, so it cannot maintain a running clock. Summary of the Invention

[0006] An object is to provide a time reading to a time reader that the time reader can verify even when the time reader is offline.

[0007] According to a first aspect, there is provided a method for providing time reading, which is executed by a system including a time server, a mobile device including a secure element, and a time reader. The method includes: synchronizing a real-time clock in the secure element with the time server; operating the real-time clock in the secure element; sending, by the time reader, a current time request to the secure element via the mobile device; receiving, by the secure element, the current time request; generating, by the secure element, a response including a current time reading from the real-time clock and password verification data, generating the response including applying a password signature and including a proof of authentication of the secure element by the time server in the password verification data; sending, by the secure element, the response to the time reader via the mobile device; receiving, by the time reader, the response from the secure element; and verifying, by the time reader, the response based on the password verification data.

[0008] According to a second aspect, there is provided a method for providing time reading, which is executed by a mobile device including a secure element, the secure element including a real-time clock. The method includes: synchronizing, by the secure element, the real-time clock with the time server; operating the real-time clock in the secure element; receiving, by the secure element, a current time request from the time reader via the mobile device; generating, by the secure element, a response including a current time reading from the real-time clock and password verification data, generating the response including applying a password signature and including a proof of authentication of the secure element by the time server in the password verification data; and sending, by the secure element, the response to the time reader via the mobile device.

[0009] Synchronization may include authenticating the time server.

[0010] The time reader may be a credential reader for evaluating access to a physical space, in which case the method further includes: interacting with the time reader using credentials stored in the mobile device to allow the time reader to evaluate access to the physical space.

[0011] The secure element may be physically tamper-proof.

[0012] The secure element may be physically tamper-evident.

[0013] According to a third aspect, there is provided a mobile device for providing time reading. The mobile device includes: a secure element including a real-time clock; a processor; and a memory storing instructions which, when executed by the processor, cause the mobile device to perform the following operations: synchronize the real-time clock with a time server by the secure element; run the real-time clock in the secure element; receive a current time request from a time reader via the mobile device by the secure element; generate a response by the secure element, the response including a current time reading from the real-time clock and password verification data, generating the response including applying a password signature and including a proof of authentication of the secure element by the time server in the password verification data; and send the response from the secure element via the mobile device to the time reader.

[0014] The instructions for synchronization may include instructions which, when executed by the processor, cause the mobile device to authenticate the time server.

[0015] The time reader may be a credential reader for evaluating access to a physical space. In this case, the mobile device further includes instructions which, when executed by the processor, cause the mobile device to interact with the time reader using credentials stored in the mobile device to allow the time reader to evaluate access to the physical space.

[0016] The secure element may be set to be physically tamper-proof.

[0017] The secure element may be set to be physically tamper-evident.

[0018] According to a fourth aspect, there is provided a computer program for providing time reading. The computer program includes computer program code which, when executed on a mobile device including a secure element having a real-time clock, causes the mobile device to perform the following operations: synchronize the real-time clock with a time server by the secure element; run the real-time clock in the secure element; receive a current time request from a time reader via the mobile device by the secure element; generate a response by the secure element, the response including a current time reading from the real-time clock and password verification data, generating the response including applying a password signature and including a proof of authentication of the secure element by the time server in the password verification data; and send the response from the secure element via the mobile device to the time reader.

[0019] According to a fifth aspect, there is provided a computer program product which includes the computer program according to the fourth aspect and a computer-readable device which includes a non-transitory memory storing the computer program.

[0020] In general, unless otherwise expressly defined herein, all terms used in the claims shall be construed according to their ordinary meaning in the technical field. Unless otherwise expressly stated, all references to "an / a / the element, apparatus, component, device, step, etc." shall be construed broadly as referring to at least one instance of the element, apparatus, component, device, step, etc. Unless expressly stated, the steps of any method disclosed herein need not be performed in the exact order disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Aspects and embodiments will now be described by way of example with reference to the accompanying drawings, in which:

[0022] Figure 1 is a schematic diagram showing an environment in which the embodiments proposed herein can be applied;

[0023] Figure 2 is a swimlane diagram showing an embodiment of a method for providing time reading performed by Figure 1 a mobile device, a time reader, and a time server;

[0024] Figure 3 is a schematic diagram showing Figure 1 and Figure 2 components of a mobile device; and

[0025] Figure 4 shows an example of a computer program product 90 including a computer-readable device. DETAILED DESCRIPTION

[0026] Aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. However, these aspects may be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of all aspects of the invention to those skilled in the art. Throughout the description, like reference numerals refer to like elements.

[0027] According to the embodiments proposed herein, time reading with improved security is provided. The mobile device includes a secure element, which in turn includes a real-time clock. The secure element is authenticated by a time server. After synchronizing the real-time clock with the time server, the real-time clock can operate. When a time reader (e.g., forming part of a credential reader for physical access) requests the current time via the mobile device, the secure element of the mobile device reads its real-time clock, generates password verification data, and provides it to the time reader in a message.

[0028] Based on the password verification data, the time reader can verify that the time server has authenticated the secure element. It is worth noting that the mobile device 2 does not need to be trusted and only acts as a provider of communication between the secure element and the time server / time reader. Using the password verification data, the time reader can also verify that the time reading has not been tampered with after the message is generated in the secure element. In this solution, as long as the time reader trusts the time server, the time reader can be offline and still trust the time reading. In addition, as long as there is a local communication path between the time reader and the mobile device, the mobile device can be offline during the time reading.

[0029] Figure 1 is a schematic diagram showing an environment in which the embodiments proposed herein can be applied.

[0030] The time server 3 is a server that can provide an accurate time reading, for example, based on the time from an NTP server. The time reader 6 is a device that requires a trustworthy time reading at least occasionally. The time reader 6 can be an offline device that does not communicate directly with the time server 3. In addition, the time reader 6 can be completely offline most of the time, at which time the time reader does not consume any energy. Therefore, it does not and cannot maintain a running clock itself. A mobile device 2 is provided, for example, in the form of a smart phone, a wearable device (such as a smart watch or smart jewelry), an electronic key, a tablet computer, or a laptop computer. Since the time reader 6 can be offline, the power consumption is limited, and the time reader can therefore be powered by a battery or even by the mobile device, for example, using an NFC (Near Field Communication) or USB (Universal Serial Bus) connection for power supply. Since the time reader 6 can be powered off, it does not have a running real-time clock.

[0031] In contrast, the mobile device 2 includes a secure element 1, which includes a real-time clock 7. The secure element 1 has hardware protection to make it physically tamper-proof. Therefore, the secure element 1 can be protected against attacks that attempt to manipulate the time of its real-time clock 7. For example, the secure element 1 can be implemented such that any attempt to open the outer layer will damage the secure element, rendering it inoperable. This can be achieved by making the adhesion of the outer layer stronger than the internal connections and component integrity of the operating part of the secure element 1. If manipulation is detected, the clock state will be reset, and the secure element will not provide any time reading. Similarly, if the real-time clock loses power, this will also be detected, and the real-time clock is reset. After the reset, the real-time clock needs to be synchronized with the time server 3 before it can operate again.

[0032] Optionally or additionally, the security element 1 has hardware protection to make physical tampering traceable. Tampering traceability means that if physical tampering is performed, this can be detected. Once tampering is detected, the security element 1 can be reset in such a way that it does not indicate the time until it is resynchronized. Alternatively, if physical tampering is detected, the security element 1 is set to a permanently unavailable state.

[0033] The security element 1 is authenticated using the time server 3. For example, the security element 1 can be cryptographically coupled to the time server 3 during production. This allows the time server 3 to trust the security element 1. For example, the security element 1 stores the public key of the time server 3, and the time server 3 stores the public key of the security element. The public key can form part of a key pair that is part of a certificate chain, or a secure hash value can be used to establish trust. In the case where the time server 3 and the security element 1 are cryptographically linked during production, the security element and the time server can establish secure communication with each other at a later time. Additionally, the security element can create a cryptographically signed timestamp that can be verified by any time reader.

[0034] The communication between the security element 1 and the time server 3 can be based on a secure channel. Additionally, the communication between the security element 1 and the time reader 6 can be based on a secure channel. As is known per se in the art, such a secure channel can be distributed to the other endpoint based on the public key of each endpoint. The security element 1 and the time server 3 are mutually authenticated, i.e., they trust each other. In the process described below, the time reader 6 authenticates the security element 1. On the other hand, the security element 1 does not need to authenticate the time reader 6 because the security element 1 can allow an anonymous time reader 6 to query the current time.

[0035] As described in more detail below, the time reader can obtain a time reading from the security element 1 via a mobile device. The security element responds with the time reading and verification data that proves to the time reader that the security element 1 has been authenticated by the time server 3 and is trusted by the time server 3. In this way, as long as the time reader trusts the time server 3, the time reader 6 can obtain the current time and can trust the reading, even if the time reader 6 has never communicated with the mobile device 2 or the security element 1 before.

[0036] The time reader 6, the mobile device 2 including the security element 1, and the time server 3 are collectively referred to as the system 10.

[0037] Figure 2 is shown by Figure 1Swimlane diagram of an embodiment of a method for providing time reading performed by mobile device 2, time reader 6, and time server. Steps performed by mobile device 2 form part of the method performed by the mobile device. Similarly, steps performed by time server 3 constitute part of the method performed by time server 3, and steps performed by time reader 6 constitute part of the method performed by time reader 6. Steps performed by mobile device 2 and server 3 together constitute part of the method performed by system 10.

[0038] In synchronization step 40, mobile device 2 synchronizes 40 its real-time clock 7 in security element 1 with time server 3. Actions performed by the time server are represented by corresponding synchronization step 50. Synchronization may include authenticating time server 3 so that the security element can trust the synchronization. Authentication may be implemented, for example, by verifying a cryptographic signature provided by time server 3 or by establishing an encrypted communication channel between security element 1 and time server 3. Synchronization may also include authenticating security element 1 using time server 3. This may be based on time server 3 having previously registered the public key of security element 1. Alternatively, security element 1 is authenticated based on a certificate authority. In any case, authentication of security element 1 is an indication that time server 3 trusts security element 1. Authentication of security element 1 may be based on the time server verifying a cryptographic signature applied by security element 1, which indicates that the security element possesses a private key associated with a public key that the time server can verify. As part of the authentication, the time server may issue a proof of authentication of security element 1 by time server 3. The authentication proof may be, for example, a cryptographic signature applied by time server 3 to the identity of security element 1. The authentication proof may be provided to mobile device 2.

[0039] It should be noted that synchronization does not need to occur frequently; once a month may be sufficient. The current real-time clock may drift by less than 1.0 second per day.

[0040] In RTC operation step 42, mobile device 2 causes real-time clock 7 to run in security element 1. In other words, the real-time clock continues to run after synchronization.

[0041] In the request time step 54, the time reader 6 sends a current time request 30 to the security element 1 via the mobile device 2. This step is performed when the time reader 6 needs to know the current time. For example, if the mobile device 2 is an electronic key with a valid time and the time reader 6 is an electronic lock, then the current time is needed to know if the electronic key was provided at a valid time. An attacker may attempt to mislead the time reader 6 with an incorrect time, for example, to cause the electronic lock to allow access with an expired electronic key. In such a case, the time reader 6 should be able to trust that the time reading is correct and has not been manipulated.

[0042] The request can be transmitted via a secure communication channel (a secure channel based on signatures or encryption using a common secret derived by both parties using Diffie - Hellman or a dedicated protocol) between the time reader 6 and the security channel 1.

[0043] In one embodiment, an encrypted communication channel is established between the time reader 6 and the security element 1 to prevent data from being manipulated, for example, by the mobile device 2.

[0044] In the receive request step 44, the mobile device 2 receives the current time request 30 (optionally via a secure communication channel). The current time request is internally routed to the security element 1.

[0045] In the generate response with time step 46, the mobile device 2 (and more specifically the security element 1) generates a response. The response includes a current time reading (e.g., a timestamp) from the real - time clock 7 and password verification data.

[0046] Generating the response includes applying a cryptographic signature to the data including the current time. Then, the cryptographic signature is (at least part of) the password verification data. The response includes in the password verification data a proof that the time server 3 authenticates the security element 1 (i.e., a proof that the time server 3 trusts the security element 1). The authentication proof can be, for example, a cryptographic signature applied by the time server 3 to the identity of the security element 1.

[0047] In the send response step 48, the mobile device 2 sends the response 32 to the time reader, optionally via a secure channel. More specifically, the security element 1 sends the response 32 to the time reader 6 via the mobile device 2.

[0048] In the receive response step 56, the time reader 6 receives the response 32 from the mobile device 2 (originating from the security element 1), optionally via a secure channel.

[0049] In verification step 58, the time reader 6 verifies the response 32 based on the password verification data. For example, when the password verification data includes a password signature, the time reader 6 can use the public key of the time server 3 to verify the password signature. The response can include a signature of the time server 3, which indicates that the time server 3 trusts the secure element 1. The signature data in the response can then include the public key of the secure element 1, thereby allowing the time reader to also verify the integrity of the data (e.g., time reading) from the secure element 1. In this way, as long as the time reader trusts the time server, the time reader can also trust the secure element. Thus, the time reader can trust the current time reading as if it directly came from the time server.

[0050] It should be noted that there can be multiple time servers, where each secure element is associated with a time server. In this case, the time reader 6 can store multiple public keys, one for each time server. The response 32 can indicate the indication of the time server 3 associated with the secure element 1, thereby allowing the time reader to use the appropriate public key to verify the password verification data.

[0051] In one embodiment, the time reader 6 is a credential reader for evaluating access to a physical space, and the mobile device is an electronic key. In this case, the mobile device 2 interacts with the time reader 6 using the credentials stored in the mobile device 2 in an optional step 49 for access control interaction to allow the time reader to evaluate access to the physical space. There is a corresponding step 59 for access control interaction at the time reader 6. When the time reader 6 authorizes access, the electronic lock can be unlocked, thereby enabling access to the physical space.

[0052] In one embodiment, the mobile device can be in the form of an electronic key having communication capabilities (e.g., using a cellular modem or via local communication with a gateway device such as a smart phone or an electronic key fob). When the electronic key is first initialized, the key forwards messages between the secure element 1 and the time server 3 to synchronize the real-time clock of the secure element. When the credential reader connected to the electronic key (or forming part of the electronic key) is used to unlock the lock, the credential reader is the time reader and communicates with the secure element 1 of the electronic key to obtain a trusted time reading. Once the trusted time reading is obtained, the credential reader can make an access decision on whether to unlock, for example, by checking the valid time of the key.

[0053] Using the embodiments presented herein, as long as the time reader trusts the time server 3, the time reader 6 can obtain the current time and can trust the reading. This is the case even if the time reader 6 has never communicated with the mobile device 2 or the security element 1 before. In addition, compared to the time reader 6 obtaining the time reading from the time server on demand via the mobile device, the time reading can occur faster and does not depend on the mobile device being online at that point in time. For many applications, the time delay in obtaining a secure timestamp from the time server may be too long. For example, consider the case of an electronic key where unlocking should occur without a perceived delay. Even an additional half-second delay can significantly degrade the user experience.

[0054] Figure 3 is a schematic diagram of the components of the mobile device 2 that Figure 1 and Figure 2 is shown. The processor 60 is provided using any combination of one or more of a suitable central processing unit (CPU), a graphics processing unit (GPU), a multi-processor, a microcontroller, a digital signal processor (DSP), etc. that are capable of executing software instructions 67 stored in the memory 64, and the memory 64 can thus be a computer program product. Alternatively, the processor 60 can be implemented using an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc. The processor 60 can be configured to execute the method described above with reference to Figure 2 description.

[0055] The memory 64 can be any combination of random access memory (RAM) and / or read only memory (ROM). The memory 64 also includes a non-transitory persistent storage device, which can be, for example, any single one or a combination of the following: magnetic memory, optical memory, solid state memory, or even remotely mounted memory.

[0056] A data memory 66 is also provided for reading and / or storing data during the execution of the software instructions in the processor 60. The data memory 66 can be any combination of RAM and / or ROM.

[0057] An I / O interface 62 is provided for communicating with external and / or internal entities using wired communication, e.g., based on wired and / or wireless communication such as local communication and / or cellular network. Local communication can be, for example, based on Wi-Fi, Bluetooth, BLE (Bluetooth Low Energy), Ethernet, USB (Universal Serial Bus), NFC (Near Field Communication), etc. As long as the principles described hereinafter are applicable, the cellular network can conform to any one or a combination of the following: the sixth generation (6G) mobile network, the next generation mobile network (fifth generation, 5G), LTE (Long Term Evolution), UMTS (Universal Mobile Telecommunications System) utilizing W-CDMA (Wideband Code Division Multiple Access), or any other current or future wireless network.

[0058] Other components of the mobile device 2 are omitted so as not to obscure the concepts presented herein.

[0059] Figure 4 An example of a computer program product 90 including a computer-readable device is shown. On this computer-readable device, a computer program 91 can be stored in a non-transitory memory. The computer program can cause a processor to execute the method according to the embodiments described herein. In this example, the computer program product is in the form of a removable solid-state memory such as a Universal Serial Bus (USB) drive. As explained above, the computer program product can also be implemented in the memory of a device such as Figure 3 the computer program product 64. Although the computer program 91 is schematically shown herein as part of a removable solid-state memory, the computer program can be stored in any manner suitable for the computer program product (e.g., another type of removable solid-state memory or an optical disc such as a CD (Compact Disc), DVD (Digital Versatile Disc), or Blu-ray Disc).

[0060] A list of embodiments enumerated in Roman numerals is now given herein from another perspective.

[0061] i. A method for providing time reading, the method being executed by a system including a time server, a mobile device including a security element, and a time reader, the method comprising:

[0062] Synchronizing a real-time clock in the security element with the time server;

[0063] Operating the real-time clock in the security element;

[0064] Sending, by the time reader via the mobile device, a current time request to the security element;

[0065] Receiving, by the security element, the current time request;

[0066] A response is generated by the security element, the response including a current time reading from the real-time clock and password verification data;

[0067] The security element sends the response to the time reader via the mobile device;

[0068] The time reader receives the response from the security element; and

[0069] The time reader verifies the response based on the password verification data.

[0070] ii. A method for providing a time reading, the method being performed by a mobile device including a security element, the security element including a real-time clock, the method comprising:

[0071] The security element synchronizes the real-time clock with a time server;

[0072] The real-time clock is made to run in the security element;

[0073] The security element receives a current time request from a time reader via the mobile device;

[0074] The security element generates a response, the response including a current time reading from the real-time clock and password verification data; and

[0075] The security element sends the response to the time reader via the mobile device.

[0076] iii. The method according to embodiment ii, wherein generating the response includes applying a cryptographic signature.

[0077] iv. The method according to embodiment iii, wherein generating the response includes including a proof of authentication of the security element by the time server in the password verification data.

[0078] v. The method according to any one of embodiments ii to iv, wherein the synchronization includes authenticating the time server.

[0079] vi. The method according to any one of embodiments ii to v, wherein the time reader is a credential reader for evaluating access to a physical space, and wherein the method further comprises:

[0080] Using the credentials stored in the mobile device to interact with the time reader to allow the time reader to evaluate access to the physical space.

[0081] vii. The method according to any one of embodiments ii to vi, wherein the security element is arranged to be physically tamper-proof.

[0082] viii. The method according to any one of embodiments ii to vii, wherein the security element is arranged to be physically tamper-evident.

[0083] ix. A mobile device for providing time reading, the mobile device comprising:

[0084] A security element including a real-time clock;

[0085] A processor; and

[0086] A memory storing instructions which, when executed by the processor, cause the mobile device to:

[0087] Synchronize the real-time clock with a time server by the security element;

[0088] Cause the real-time clock to run in the security element;

[0089] Receive a current time request from a time reader by the security element via the mobile device;

[0090] Generate a response by the security element, the response including a current time reading from the real-time clock and password verification data; and

[0091] Send the response from the security element to the time reader via the mobile device.

[0092] x. The mobile device according to embodiment ix, wherein the instructions for generating the response include instructions which, when executed by the processor, cause the mobile device to apply a cryptographic signature.

[0093] xi. The mobile device according to embodiment x, wherein the instructions for generating the response include instructions which, when executed by the processor, cause the mobile device to include a proof of authentication of the security element by the time server in the password verification data.

[0094] xii. The mobile device according to any one of embodiments ix to xi, wherein the instructions for synchronization include instructions which, when executed by the processor, cause the mobile device to authenticate the time server.

[0095] xiii. The mobile device according to any one of embodiments ix to xii, wherein the time reader is a credential reader for evaluating access to a physical space, and wherein the mobile device further comprises instructions which, when executed by the processor, cause the mobile device to interact with the time reader using credentials stored in the mobile device to allow the time reader to evaluate access to the physical space.

[0096] xiv. The mobile device according to any one of embodiments ix to xiii, wherein the security element is arranged to be physically tamper-proof.

[0097] xv. The mobile device according to any one of embodiments ix to xiv, wherein the security element is arranged to be physically tamper-evident.

[0098] xvi. A computer program for providing time reading, the computer program comprising computer program code which, when executed on a mobile device comprising a security element including a real-time clock, causes the mobile device to:

[0099] Synchronize the real-time clock with a time server by the security element;

[0100] Cause the real-time clock to run in the security element;

[0101] Receive a current time request from a time reader via the mobile device by the security element;

[0102] Generate a response by the security element, the response including a current time reading from the real-time clock and password authentication data; and

[0103] Send the response to the time reader via the mobile device by the security element.

[0104] xvii. A computer program product comprising the computer program according to embodiment xvi and a computer-readable device, the computer-readable device comprising a non-transitory memory storing the computer program.

[0105] Aspects of the present disclosure have been mainly described above with reference to several embodiments. However, as will be readily understood by those skilled in the art, other embodiments are equally possible within the scope of the invention as defined by the appended patent claims, in addition to the embodiments disclosed above. Thus, while aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The aspects and embodiments disclosed herein are for illustrative purposes and are not intended to be limiting, where the true scope and gist are indicated by the appended claims.

Claims

1. A method for providing time reading, the method being executed by a system (10) comprising a time server (3), a mobile device (2) including a security element (1), and a time reader (6), the method comprises: synchronizing (40, 50) a real-time clock (7) in the security element (1) with the time server (3); operating (42) the real-time clock (7) in the security element (1); sending (54) a current time request (30) from the time reader (6) to the security element (1) via the mobile device (2); receiving (44) the current time request (30) by the security element (1); generating (46) a response by the security element (1), the response including a current time reading from the real-time clock (7) and password verification data, wherein generating the response includes: applying a password signature, and including a proof of authentication of the security element (1) by the time server (3) in the password verification data; sending (48) the response (32) from the security element (1) to the time reader (6) via the mobile device (2); receiving (56) the response (32) by the time reader (6) from the security element; and verifying (58) the response (32) by the time reader (6) based on the password verification data.

2. A method for providing time reading, the method being executed by a mobile device (2) including a security element (1), the security element (1) including a real-time clock (7), the method comprises: synchronizing (40) the real-time clock (7) in the security element with a time server (3); operating (42) the real-time clock (7) in the security element (1); receiving (44) a current time request (30) from a time reader (6) by the security element (1) via the mobile device (2); generating (46) a response by the security element (1), the response including a current time reading from the real-time clock (7) and password verification data, wherein generating the response includes: applying a password signature, and including a proof of authentication of the security element (1) by the time server (3) in the password verification data; and sending (48) the response (32) from the security element (1) to the time reader (6) via the mobile device (2).

3. The method according to claim 2, wherein, the proof of authentication includes a password signature applied by the time server (3) to the identity of the security element (1).

4. The method according to claim 2 or 3, wherein, the synchronization (40) includes authenticating the time server (3).

5. The method according to any one of claims 2 to 4, wherein, the time reader (6) is a credential reader for evaluating access to a physical space, and wherein the method further comprises: Interact (49) with the time reader (6) using the credentials stored in the mobile device (2) to allow the time reader to evaluate access to the physical space.

6. The method according to any one of claims 2 to 5, wherein, the security element (1) is configured to be physically tamper-proof.

7. The method according to any one of claims 2 to 6, wherein, the security element (1) is configured to be physically tamper-evident.

8. A mobile device (2) for providing time reading, the mobile device (2) comprising: a security element (1) including a real-time clock (7); a processor (60); and a memory (64) storing instructions (67) which, when executed by the processor, cause the mobile device (2) to perform the following operations: synchronize the real-time clock (7) with a time server (3) by the security element; cause the real-time clock (7) to run in the security element (1); receive (44) a current time request (30) from a time reader (6) by the security element (1) via the mobile device (2); generate, by the security element (1), a response including a current time reading from the real-time clock (7) and password verification data, wherein generating the response includes: applying a password signature, and including a proof of authentication of the security element (1) by the time server (3) in the password verification data; and send (48) the response (32) from the security element (1) to the time reader (6) via the mobile device (2).

9. The mobile device (2) according to claim 8, wherein, the proof of authentication includes a password signature applied by the time server (3) to the identity of the security element (1).

10. The mobile device (2) according to claim 8 or 9, wherein, the instructions for synchronization include instructions (67) which, when executed by the processor, cause the mobile device (2) to authenticate the time server (3).

11. The mobile device (2) according to any one of claims 8 to 10, wherein, the time reader (6) is a credential reader for evaluating access to a physical space, and wherein the mobile device further includes instructions (67) which, when executed by the processor, cause the mobile device (2) to interact with the time reader (6) using the credentials stored in the mobile device (2) to allow the time reader to evaluate access to the physical space.

12. The mobile device (2) according to any one of claims 8 to 11, wherein, the security element (1) is configured to be physically tamper-proof.

13. The mobile device (2) according to any one of claims 8 to 12, wherein, the security element (1) is configured to be physically tamper-evident.

14. A computer program (67, 91) for providing time reading, the computer program comprising computer program code which, when executed on a mobile device (2) comprising a secure element (1) containing a real-time clock (7), causes the mobile device (2) to perform the following operations: Synchronize the real-time clock (7) with a time server (3) by the secure element; Cause the real-time clock (7) to run in the secure element (1); Receive a current time request (30) from a time reader (6) by the secure element (1) via the mobile device (2); Generate a response by the secure element (1), the response comprising a current time reading from the real-time clock (7) and password verification data, wherein generating the response comprises: applying a cryptographic signature, and including in the password verification data a proof of authentication of the secure element (1) by the time server (3); and Send the response (32) from the secure element (1) via the mobile device (2) to the time reader (6).

15. A computer program product (64, 90), the computer program product (64, 90) comprising the computer program according to claim 14 and a computer-readable device, the computer-readable device comprising a non-transitory memory storing the computer program.

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