Enabling temporary access to a physical space

Abstract

It is provided a method for enabling temporary access to a physical space (16) secured by an electronic lock (12). The method being performed by an access right generator (1). The method comprises: obtaining (40) a user identifier of a user (5), and a time data item defining a validity time; obtaining (42) a cryptographic key; generating (44) an access object (21) based on the user identifier, the time data item and the cryptographic key, to enable an electronic lock to cryptographically verify the user identifier based on the access object (21); and providing (46) the access object (21) to the user.

Description

ENABLING TEMPORARY ACCESS TO A PHYSICAL SPACETECHNICAL FIELD

[0001] The present disclosure relates to the field of access control to physical spaces, and in particular to enabling temporary access to a physical space secured by an electronic lock.BACKGROUND

[0002] Locks and keys are evolving from the traditional pure mechanical locks.These days, electronic locks are becoming increasingly common. For electronic locks, no mechanical key profile is needed for authentication of a user. The electronic locks can e.g. be opened using an electronic key stored on a special carrier (fob, card, etc.) or in a smartphone. The electronic key and electronic lock can e.g. communicate over a wireless interface. Such electronic locks provide a number of benefits, including improved flexibility in management of access rights, audit trails, key management, etc.

[0003] At times, an owner or user of such an electronic lock may desire to grant temporary access to a user. This can e.g. be for someone to perform a service, such as cleaning, plumbing, etc. Alternatively, the property is rented out, where temporary access to the property should be granted.

[0004] In many installations, it is desired that the electronic lock is an offline lock. This implies that the lock does not have capability to, at will, communicate with a backend, e.g. to get updated access rights or verification details.

[0005] For such offline locks, it is particularly difficult to solve a problem of providing temporary access for a user. How can the offline lock securely determine whether to grant temporary access an approaching user, which might not have been at the site of the offline lock before?SUMMARY

[0006] One object is to improve how to enable temporary access to a physical space,

[0007] In some aspects, the embodiments described herein relate to a method for enabling temporary access to a physical space secured by an electronic lock. The method being performed by an access right generator. The method comprises: obtaining a user identifier of a user, and a time data item defining a validity time; obtaining a cryptographic key; generating an access object based on the user identifier, the time data item and the cryptographic key, to enable an electronic lock to cryptographically verify the user identifier based on the access object (21); and providing the access object to the user.

[0008] In some aspects, the embodiments described herein relate to a method wherein the cryptographic key is a symmetric key that is also available to the electronic lock, and wherein the generating comprises performing an encryption using the symmetric key.

[0009] In some aspects, the embodiments described herein relate to a method wherein the cryptographic key is a secret key of a cryptographic keypair also comprising a public key, wherein the cryptographic keypair is associated with the access right generator.

[0010] In some aspects, the embodiments described herein relate to a method wherein the user identifier is in the form of a public key of a cryptographic keypair associated with the user.

[0011] In some aspects, the embodiments described herein relate to the user identifier is in the form of an e-mail address included in a certificate also comprising a public key of a cryptographic keypair associated with the user identifier forming part of a certificate for the user.

[0012] In some aspects, the embodiments described herein relate to a method wherein the providing the access object to the user comprises providing the access object to an application executing in a user device of the user.

[0013] In some aspects, the embodiments described herein relate to a method wherein the providing the access object to the user comprises sending a text message toa user device of the user, wherein the text message comprises a string comprising a character encoding of the access object.

[0014] In some aspects, the embodiments described herein relate to a method wherein the generating the access object comprises generating the access object based on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock.

[0015] In some aspects, the embodiments described herein relate to a method wherein the generating the access object comprises using the user identifier, the time data item and the cryptographic key as inputs to a one-way function, and determining a personal identification number, PIN, based on the output from the one-way function.

[0016] In some aspects, the embodiments described herein relate to a method wherein the determining a PIN comprises employing a predetermined PIN extraction function on the output from the one-way function.

[0017] In some aspects, the embodiments described herein relate to a method wherein the generating the access object comprises generating a cryptographic signature based on the user identifier, the time data item and the cryptographic key, and wherein the access object comprises the cryptographic signature and the time data item, while the access object omits the user identifier and the cryptographic data item.

[0018] In some aspects, the embodiments described herein relate to an access right generator for enabling temporary access to a physical space secured by an electronic lock. The access right generator comprises: processing circuitry; and memory circuitry storing instructions that, when executed by the processing circuitry, cause the access right generator to: obtain a user identifier of a user, and a time data item defining a validity time; obtain a cryptographic key; generate an access object based on the user identifier, the time data item and the cryptographic key, to enable an electronic lock to cryptographically verify the user identifier based on the access object (21); and provide the access object to the user.

[0019] In some aspects, the embodiments described herein relate to a computer program for enabling temporary access to a physical space secured by an electronic lock.The computer program comprises computer program code which, when executed on a access right generator causes the access right generator to: obtain a user identifier of a user, and a time data item defining a validity time; obtain a cryptographic key; generate an access object based on the user identifier, the time data item and the cryptographic key; and provide the access object to the user.

[0020] In some aspects, the embodiments described herein relate to a computer program product comprising the computer program and a computer readable means comprising non-transitory memory in which the computer program is stored.

[0021] In some aspects, the embodiments described herein relate to a method for enabling temporary access to a physical space secured by an electronic lock. The method is performed by the electronic lock. The method comprises: obtaining a user identifier of a user, and a time data item defining a validity time; obtaining a cryptographic key; generating a validation object based on the user identifier, the time data item and the cryptographic key; obtaining an access object from a user; and granting access to the physical space based on the validation object matching the access object.

[0022] In some aspects, the embodiments described herein relate to a method wherein the cryptographic key is a symmetric key that is also available to an access right generator that generated the access object, and wherein the generating comprises performing an encryption using the symmetric key.

[0023] In some aspects, the embodiments described herein relate to a method wherein the cryptographic key is a public key of a cryptographic keypair also comprising a secret key, wherein the cryptographic keypair is associated with the access right generator.

[0024] In some aspects, the embodiments described herein relate to a method wherein the user identifier is in the form of a public key of a cryptographic keypair associated with the user.

[0025] In some aspects, the embodiments described herein relate to the user identifier is in the form of an e-mail address included in a certificate also comprising apublic key of a cryptographic keypair associated with the user identifier forming part of a certificate for the user.

[0026] In some aspects, the embodiments described herein relate to a method wherein the obtaining the access object from the user comprises receiving the access object from an application executing in a user device of the user.

[0027] In some aspects, the embodiments described herein relate to a method wherein the generating the validation object comprises generating the validation object based on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock.

[0028] In some aspects, the embodiments described herein relate to a method wherein the generating the validation object comprises using the user identifier, the time data item and the cryptographic key as inputs to a one-way function, and determining a personal identification number, PIN, based on the output from the oneway function.

[0029] In some aspects, the embodiments described herein relate to a method, wherein the determining a PIN comprises employing a predetermined PIN extraction function on the output from the one-way function.

[0030] In some aspects, the embodiments described herein relate to a method wherein the access object comprises a cryptographic signature based on the user identifier and the time data item, and wherein the granting access comprises matching the validation object against the cryptographic signature.

[0031] In some aspects, the embodiments described herein relate to an electronic lock for enabling temporary access to a physical space secured by an electronic lock. The electronic lock comprises: processing circuitry; and memory circuitry storing instructions that, when executed by the processing circuitry, cause the electronic lock to: obtain a user identifier of a user, and a time data item defining a validity time; obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key, to enable an electronic lock to cryptographically verify the user identifier based on the access object (21); obtain an access object from auser; and grant access to the physical space based on the validation object matching the access object.

[0032] In some aspects, the embodiments described herein relate to a computer program for enabling temporary access to a physical space secured by an electronic lock. The computer program comprises computer program code which, when executed on an electronic lock causes the electronic lock to: obtain a user identifier of a user, and a time data item defining a validity time; obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key; obtain an access object from a user; and grant access to the physical space based on the validation object matching the access object.

[0033] In some aspects, the embodiments described herein relate to a computer program product comprising the computer program and a computer readable means comprising non-transitory memory in which the computer program is stored.

[0034] In some aspects, the embodiments described herein relate to a system for enabling temporary access to a physical space secured by an electronic lock, the system comprising an access right generator and the electronic lock. The access right generator comprises: processing circuitry; and memory circuitry storing instructions that, when executed by the processing circuitry, cause the access right generator to: obtain a user identifier of a user, and a time data item defining a validity time; obtain a cryptographic key; generate an access object based on the user identifier, the time data item and the cryptographic key, to enable the electronic lock to cryptographically verify the user identifier based on the access object; and provide the access object to the user. The electronic lock comprises: processing circuitry; and memory circuitry storing instructions that, when executed by the processing circuitry, cause the electronic lock to: obtain the user identifier of the user, and a time data item defining a validity time; obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key; obtain the access object from the user; and grant access to the physical space based on the validation object matching the access object.

[0035] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which:

[0037] Fig 1 is a schematic diagram illustrating an environment in which embodiments presented herein can be applied;

[0038] Figs 2A-C are schematic diagrams illustrating various embodiments disclosing how an access object from the access right generator is provided to the electronic lock for access evaluation;

[0039] Fig 3 is a swimlane diagram illustrating embodiments of methods for enabling temporary access to a physical space secured by an electronic lock;

[0040] Fig 4 is a schematic diagram illustrating components of the access right generator and the user device of Fig 1; and

[0041] Fig 5 shows one example of a computer program product comprising computer readable means.DETAILED DESCRIPTION

[0042] The 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. These aspects may, however, 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 thoroughand complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0043] According to embodiments presented herein, it is provided an improved solution to how a user gains temporary access to a physical object. Specifically, an access object is generated by an access right generator based on an identifier of the user, a cryptographic key, as well as a time data item defining a validity time. The access object is provided to the user. When the user approaches the electronic lock, the access object is provided to the electronic lock. The electronic lock generates a validation object based on the user identifier, a cryptographic key (that is associated with or is the same as the cryptographic key that is used in the generation of the access object), and the time data item. When the access object and the validation object match, access is granted. The cryptographic key(s) are used to ensure that the access object is generated by the access right generator 1. By using the user identifier in generating both the access object and the validation object, the electronic lock can verify the access object even though the user might not have been by the electronic lock before. More details on this solution are provided below.

[0044] Fig 1 is a schematic diagram illustrating an environment in which embodiments presented herein can be applied. Access to a physical space 16 is restricted by an openable physical barrier 15 which is selectively unlockable. The physical barrier 15 stands between the restricted physical space 16 and an accessible physical space 14. Note that the accessible physical space 14 can be a restricted physical space in itself, but in relation to this physical barrier 15, the accessible physical space 14 is accessible. The barrier 15 can be a door, gate, hatch, cabinet door, drawer, window, etc. An electronic lock 12 is provided in order to control access to the physical space 16, by selectively unlocking the barrier 15.

[0045] The electronic lock 12 can be provided in a structure 17 (such as a wall, fence, etc.) surrounding the barrier 15 (as shown), or the electronic lock 12 can be provided in the barrier 15 itself (not shown). The electronic lock 12 is controllable to be in a locked state or in an unlocked state. Optionally, the electronic lock 12 comprises a user input device 13, e.g. a keypad or touchscreen, for entry of a passcode, e.g. a pin or an alphanumeric sequence, to unlock the electronic lock 12. Optionally, the electronic lock12 is made up of separate units of an access control device (that evaluates access) and the electronically controllable lock, whose lock / unlocked state is controlled by the access control device.

[0046] Optionally, the electronic lock 12 supports one or more additional factors of authentication, e.g. by communicating with an electronic key, or biometrics.

[0047] A communication network 7, which can be an internet protocol (IP)-based network, is provided. The communication network 7 can e.g. comprise any one or more of a local wireless network, a cellular network, a wired local-area network, a wide-area network (such as the Internet), etc. An access right generator 7 is connected to the communication network 7.

[0048] A user 5 desires temporary access to the restricted physical space 16. The user 5 has access to a user device 2, which can be a smartphone, wearable device, tablet computer, etc., that is connected, at least part of the time, to the communication network 7. As explained in more detail below, the user 5 receives an access object via the user device 2, for unlocking the electronic lock 12 to gain access to the restricted physical space 16.

[0049] An access right generator 1 is also in connected to the communication network 7. The access right generator 1 can be implanted in the form of a server, or any other suitable computer device that is capable of performing the role of the access right generator 1 as laid forth herein.

[0050] Figs 2A-C are schematic diagrams illustrating various embodiments disclosing how an access object 21 from the access right generator 1 is provided to the electronic lock 12 for access evaluation.

[0051] Looking first to Fig 2A, the access right generator 1 generates an access object 21 in the form of a personal identification number (PIN). The PIN is provided to the user device 2 in a text message 25, such as a short messaging service (SMS) message, multimedia messaging service (MMS) message, or an IP based messaging service, such as WhatsApp, Facebook Messaging, Snapchat, etc. In this embodiment, the user 5 reads 30 the text message 25 and inputs 31 the PIN on the user input device 13 of theelectronic lock 12. This embodiment can be implemented without any modification or additional software on the user device 2. The user device 2 only needs to be able to receive text messages. Alternatively, the PIN can be provided to the user 5 without text messaging, e.g. over a phone call or even on a piece of paper.

[0052] Looking now to Fig 2B, this embodiment is similar to Fig 2A. Again, the access right generator 1 provides the access object 21 in the form of a PIN to the user device 2 in a text message 25, and the user 5 reads 30 the text message 25. Here, however, the user 5 inputs 31’ the PIN into an application (app) 20 running in the user device 2. The app 20 then communicates 32 the PIN to the electronic lock 12 over a short-rage wireless communication channel 22, e.g. based on Bluetooth, Bluetooth Low Energy (BLE), Near-Field Communication (NFC), or any other suitable current or future communication standard for short-range wireless communication.

[0053] Looking now to Fig 2C, this embodiment eliminates the need for manual user input. The text message 25 includes a string comprising a character encoding of the access object 21. The access object 21 can be a PIN, as for the embodiments of Figs 2A-B, or the access object 21 can be a more extensive access object 21, i.e. an access object made up of more data. The access object 21 can even be a binary access object 21, encoded into text, e.g. using Base64, Base58, Base32 or hexadecimal encoding. The text message 25 can contain a deep link to launch the local app in the user device 2. As an illustratory example, the text message 25 can contain the following snippet: appi d : / / / ?o=e29tYWN jZXNzlG9i amvj dAHd

[0054] In the exemplary snippet above, appid denotes an identifier of the app in the user device 2 and the text after the “o=” is the base64 encoded binary access object 21. The base64 encoded binary access object 21 can be significantly longer, as long as it fits within the text message 25. It is to be noted that instead of the access object being communicated from the access right generator 1 to the user device 2 via a text message 25, the access right generator 1 can optionally communicate directly with the app 20 in the user device 2, e.g. using the communication network 7.

[0055] In this embodiment, the user does not need to manually enter any part of the access object 21; the access object 21 is relayed to the app in the user device 2. As for the embodiment illustrated by Fig 2B, the app communicates with the electronic lock 12 over a short-range wireless communication channel to provide the access object 21 to the electronic lock 12 for access evaluation.

[0056] Fig 3 is a swimlane diagram illustrating embodiments of methods for enabling temporary access for a user 5 to a physical space 16 secured by an electronic lock. Optionally, a system 3 comprises the access right generator 1 and the electronic lock 12. The swimlane diagrams can be considered to comprise a flow chart for methods in the access right generator 1 in the leftmost swimlane and a flow chart for methods in the electronic lock 12 in the rightmost swimlane. Communication between the various entities is also shown. Prior to the methods illustrated by Fig 3 commencing, the access right generator 1 have been authorised by an owner or administrator of the electronic lock 12 to generate an access object that is a data item that is usable by the user 5 to gain access to the physical space 16 secured by the electronic lock 12.

[0057] In an obtain user identifier step 40, the access right generator 1 obtains a user identifier of a user 5, and a time data item defining a validity time. The user identifier can be in the form of a public key of a cryptographic keypair associated with the user. Alternatively, the user identifier is an identity forming part of a certificate for the user, e.g. an e-mail address of the user included in the certificate also comprising the public key of the cryptographic keypair associated with the user. Hence, the certificate also contains the public key of a cryptographic keypair associated with the user, to allow cryptographical verification of the e-mail address. Hence, the user identity can be one that can be cryptographically verified by the lock. The format of the time data item can be any suitable format, depending on the scale of the validity time. For instance, if the validity time is defined per day, the time data item can be in the form of a representation of a date, e.g. a string in the format of YYMMDD (YY = year, MM = month and DD = day of month), or a binary representation of the date.

[0058] In an obtain cryptographic key step 42, the access right generator 1 obtains a cryptographic key. In one embodiment, the cryptographic key is a symmetric key that is also available to the electronic lock 12. In one embodiment, the cryptographic key is asecret key of a cryptographic keypair also comprising a public key, wherein the cryptographic keypair is associated with the access right generator. The cryptographic key can be obtained from a local memory or a secure remote memory, available to the access right generator i.

[0059] In a generate access object step 44, the access right generator 1 generates an access object 21 based on the user identifier, the time data item and the cryptographic key, to enable an electronic lock to cryptographically verify the user identifier based on the access object 21 (using the validation object generation explained below). For instance, the user identifier, the time data item can be input (e.g. as a concatenated data item) to a one-way function (e.g. a hash function such as SHA (secure hash function) -2, -3), resulting in a hash. The hash can then be secured by the cryptographic key.

[0060] When the cryptographic key is a symmetric key, the access object 21 can be generated based on performing an encryption using the symmetric key, e.g. an encryption of the hash described above.

[0061] Optionally, the access object 21 is generated also based on an identifier associated with the electronic lock. Hence, in such an embodiment, the access object 21 is generated based on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock. The identifier associated with the electronic lock can be a lock identifier (i.e. an identifier of the electronic lock in question), or a group identifier, identifying a group of locks to which the electronic lock in question belongs. Building on the embodiment of the hash mentioned above, the hash can be based on a concatenation of the user identifier, the time data item and the identifier of the electronic lock, which is secured using the cryptographic key.

[0062] In one embodiment, the access object 21 is in the form of a PIN. In this case, the access right generator 1 uses the user identifier, the time data item and the cryptographic key as inputs to a one-way function, e.g. the hash function as described above. Subsequently, the PIN is determined based on the output from the one-way function. For instance, PIN can be determined by employing a predetermined PIN extraction function on the output from the one-way function. The PIN extraction function can e.g. be used to extract a sequence of digits from a number representation ofthe access object. For instance the hash can be converted to decimal format, and a fourdigit PIN can be obtained by extracting digits 2, 5, 7 and 8 from the decimal-format access object.

[0063] In one embodiment, when the cryptographic key is a secret key of a asymmetric keypair comprising a public key and the secret key, the generating the access object 21 comprises generating a cryptographic signature based on the user identifier, the time data item and the cryptographic key. Hence, the access object 21 comprises the cryptographic signature and the time data item, while the access object 21 omits the user identifier and the cryptographic data item. This keeps the size of the access object 21 small since the size of the signature can be configured to have a size that fits within the size limit of a standard SMS text message. Since the user identifier and cryptographic data item (e.g. the public key of the signer) is known to the user device and / or lock, the size of the access object 21 can be kept small. The public key of the signer can be stored as configuration in the user device and / or lock to recompose the full access object. By omitting data that can be derived from the communication context, the access object can be so small that, when Base64 encoded, it will still fit in a standard SMS message of 160 characters.

[0064] In a provide access object step 46, the access right generator 1 provides the access object 21 to the user 2 (or the user device 2 of the user 5). As described above with reference to Figs 2A-B, for communicating the access object 21, the access right generator 1 can send a text message 25 to a user device of the user, wherein the text message 25 comprises a string comprising a character encoding of the access object 21. The string can comprise a PIN or a string representation of a binary access object 21.

[0065] As explained above with reference to Fig 2C, the access right generator 1 can provide the access object 21 to the user using by providing the access object 21 to an application executing in a user device 2 of the user 5.

[0066] The user 5 (or the user device 2) temporarily stores the access object 100 and provides the access object 21 to the electronic lock 12, e.g. as explained with reference to Figs 2A-C above.

[0067] In an obtain user identifier and time data step 140, the electronic lock 12 obtains a user identifier of a user 5, and a time data item defining a validity time. The time data item can be obtained from the user device, or the electronic lock 12 can determine the time data item based on the current time. Optionally, the electronic lock 12 can determine a set of a plurality of potentially valid time data items, for generating a set of corresponding validation objects (see below). As explained above, the user identifier can be in the form of a public key of a cryptographic keypair associated with the user. In any case, both the time data item and the user identifier are in the same format that was used for generating the access object.

[0068] The user identifier can be obtained in communication with the user device 2. The integrity of the public key can be verified with the user device 2, thus ensuring that the user device 2 is the same one that the access object 21 was generated for.

[0069] In an obtain cryptographic key step 142, the electronic lock 12 obtains a cryptographic key, corresponding to the cryptographic key that was used for generating the access object 21. For instance, the cryptographic key can be a symmetric key that is also available to the access right generator 1 that generated the access object 21. Alternatively, the cryptographic key is a public key of a cryptographic keypair also comprising a secret key, wherein the cryptographic keypair is associated with the access right generator.

[0070] In a generate validation object step 144, the electronic lock 12 generates a validation object based on the user identifier, the time data item and the cryptographic key. The generation of the validation object corresponds to the generation of the access object 21.

[0071] Hence, when the cryptographic key is a symmetric key, the validation object can be generated based on performing an encryption using the symmetric key, as described above for the generation of the access object 21.

[0072] Optionally, the validation object is generated also based on an identifier associated with the electronic lock, when such an identifier is used to generate the access object 21. Hence, in such an embodiment, the validation object is generatedbased on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock. The identifier associated with the electronic lock is in the same format that was used for the generation of the access subject, and can thus be a lock identifier (i.e. an identifier of the electronic lock in question), or a group identifier, identifying a group of locks to which the electronic lock in question belongs.

[0073] In one embodiment, the validation object (in correspondence when used for the access object 21) is in the form of a PIN. In this case, the electronic lock 12 uses the user identifier, the time data item and the cryptographic key as inputs to a one-way function. Subsequently, the PIN is determined based on the output from the one-way function. For instance, PIN can be determined by employing a predetermined PIN extraction function on the output from the one-way function. In any case, the PIN is determined in the same manner as the PIN is determined by the access right generator 1.

[0074] In one embodiment, the cryptographic key is a public key of cryptographic keypair also comprising a secret key, wherein the cryptographic keypair is associated with the access right generator 1 (when the access right generator 1 applies the secret key for generating a signature). In this case, the access object 21 comprises the cryptographic signature and the time data item, while the access object 21 omits the user identifier and the cryptographic data item. As explained above, the user identifier can be obtained separately from the user device 2. The public key can have been provided to the electronic lock 12 previously, e.g. at installation.

[0075] In an obtain access object step 146, the electronic lock 12 obtains an access object 21 from a user. For instance, the access object 21 can be received from an application executing in a user device 2 of the user 5. Alternatively, the access object 21 is received in the form of a PIN that the user enters on the user input device 13 of the electronic lock 12.

[0076] It is to be noted that the obtain access step 146 may be performed prior to the obtain user identifier and time data step 140. In one embodiment, the obtain access object step 146 can be a trigger for the rest of the steps of the electronic lock 12.

[0077] In a conditional grant access step 148, the electronic lock 12 grants access to the physical space 16 based on the validation object matching the access object 21.

[0078] When the cryptographic key is a public key of cryptographic keypair also comprising a secret key, the granting access comprises matching the validation object against the cryptographic signature.

[0079] The cryptographic key(s) are used to ensure that the access object is generated by the access right generator 1. By using the user identifier in generating both the access object and the validation object, the electronic lock, the electronic lock can verify the access object even though the user might not have been by the electronic lock before.

[0080] When a match occurs, access is granted 150. Otherwise access is denied 152.

[0081] Fig 4 is a schematic diagram illustrating components of the access right generator 1 and the user device 2 of Fig 1. Processing circuitry 60 is provided using any combination of one or more of a suitable central processing unit (CPU), graphics processing unit (GPU), multiprocessor, neural processing unit (NPU), microcontroller, digital signal processor (DSP), etc., capable of executing software instructions 67 stored in memory circuitry 64, which can thus be a computer program product. The processing circuitry 60 could alternatively be implemented using an application specific integrated circuit (ASIC), field programmable gate array (FPGA), etc. The processing circuitry 60 can be configured to execute the respective methods of the access right generator 1 and the user device 2 described with reference to Fig 3 above.

[0082] The memory circuitry 64 can be any combination of random-access memory (RAM) and / or read-only memory (ROM). The memory circuitry 64 also comprises non- transitory persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid-state memory or even remotely mounted memory.

[0083] A data memory 66 is also provided for reading and / or storing data during execution of software instructions in the processing circuitry 60. The data memory 66 can be any combination of RAM and / or ROM.

[0084] An 1 / O interface 62 for communicating with external and / or internal entities. Optionally, the I / O interface 62 also includes a user interface, e.g. the user input device 13 of the electronic lock 12, or a conventional user interface (e.g. touch screen, buttons, speaker, microphone etc.) of the user device 2.

[0085] An I / O interface 62 is provided for communicating with external and / or internal entities using wired communication, e.g. based on Ethernet, and / or wireless communication, e.g. Wi-Fi, Bluetooth, Bluetooth Low Energy, and / or a cellular network, complying with any one or a combination of sixth generation (6G) mobile networks, next generation mobile networks (fifth generation, 5G), LTE (Long Term Evolution), UMTS (Universal Mobile Telecommunications System) utilising W-CDMA (Wideband Code Division Multiplex), or any other current or future wireless network, as long as the principles described hereinafter are applicable.

[0086] Other components of the access right generator 1 and the user device 2 are omitted in order not to obscure the concepts presented herein.

[0087] Fig 5 shows one example of a computer program product 90 comprising computer readable means. On this computer readable means, a computer program 91 can be stored in a non-transitory memory. The computer program can cause processing circuitry to execute a method according to embodiments described herein. In this example, the computer program product 90 is in the form of a removable solid-state memory, e.g. a Universal Serial Bus (USB) drive. As explained above, the computer program product could also be embodied in a memory of a device, such as the computer program product 64 of Fig 4. While the computer program 91 is here schematically shown as a section of the removable solid-state memory, the computer program can be stored in any way which is suitable for the computer program product, such as another type of removable solid-state memory, or an optical disc, such as a CD (compact disc), a DVD (digital versatile disc) or a Blu-Ray disc.

[0088] The aspects of the present disclosure have mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. Thus, whilevarious aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

Claims

CLAIMS1. A method for enabling temporary access to a physical space (16) secured by an electronic lock (12), the method being performed by an access right generator (1), the method comprising: obtaining (40) a user identifier of a user (5), and a time data item defining a validity time; obtaining (42) a cryptographic key; generating (44) an access object (21) based on the user identifier, the time data item and the cryptographic key, to enable the electronic lock to cryptographically verify the user identifier based on the access object (21); and providing (46) the access object (21) to the user.

2. The method according to claim 1, wherein the cryptographic key is a symmetric key that is also available to the electronic lock (12), and wherein the generating (144) comprises performing an encryption using the symmetric key.

3. The method according to claim 1, wherein the cryptographic key is a secret key of a cryptographic keypair also comprising a public key, wherein the cryptographic keypair is associated with the access right generator.

4. The method according to any one of the preceding claims, wherein the user identifier is in the form of a public key of a cryptographic keypair associated with the user.

5. The method according to any one of claims 1 to 3, wherein the user identifier is in the form of an e-mail address included in a certificate also comprising a public key of a cryptographic keypair associated with the user identifier forming part of a certificate for the user.

6. The method according to any one of the preceding claims, wherein the providing (46) the access object (21) to the user comprises providing the access object (21) to an application executing in a user device (2) of the user (5).

7. The method according to any one of the preceding claims, wherein the providing (46) the access object (21) to the user comprises sending a text message (25) to a userdevice of the user, wherein the text message (25) comprises a string comprising a character encoding of the access object (21).

8. The method according to any one of the preceding claims, wherein the generating (44) the access object (21) comprises generating the access object (21) based on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock.

9. The method according to any one of the preceding claims, wherein the generating (44) the access object (21) comprises using the user identifier, the time data item and the cryptographic key as inputs to a one-way function, and determining a personal identification number, PIN, based on the output from the one-way function.

10. The method according to claim 9, wherein the determining a PIN comprises employing a predetermined PIN extraction function on the output from the one-way function.

11. The method according to any one of claims 3 to 9 when dependent on claim 3, wherein the generating (44) the access object (21) comprises generating a cryptographic signature based on the user identifier, the time data item and the cryptographic key, and wherein the access object (21) comprises the cryptographic signature and the time data item, while the access object (21) omits the user identifier and the cryptographic data item.

12. An access right generator (1) for enabling temporary access to a physical space (16) secured by an electronic lock (12), the access right generator (1) comprising: processing circuitry (60); and memory circuitry (64) storing instructions (67) that, when executed by the processing circuitry, cause the access right generator (1) to: obtain a user identifier of a user (5), and a time data item defining a validity time; obtain a cryptographic key; generate an access object (21) based on the user identifier, the time data item and the cryptographic key, to enable the electronic lock to cryptographically verify the user identifier based on the access object (21); and provide the access object (21) to the user.13- A computer program (67, 91) for enabling temporary access to a physical space (16) secured by an electronic lock (12), the computer program comprising computer program code which, when executed on a access right generator (1) causes the access right generator (1) to: obtain a user identifier of a user (5), and a time data item defining a validity time; obtain a cryptographic key; generate an access object (21) based on the user identifier, the time data item and the cryptographic key, to enable the electronic lock to cryptographically verify the user identifier based on the access object (21); and provide the access object (21) to the user.

14. A computer program product (64, 90) comprising a computer program according to claim 13 and a computer readable means comprising non-transitory memory in which the computer program is stored.

15. A method for enabling temporary access to a physical space (16) secured by an electronic lock (12), the method being performed by the electronic lock (12), the method comprising: obtaining (140) a user identifier of a user (5), and a time data item defining a validity time; obtaining (142) a cryptographic key; generating (144) a validation object based on the user identifier, the time data item and the cryptographic key; obtaining (146) an access object (21) from a user; and granting (148) access to the physical space (16) based on the validation object matching the access object (21).

16. The method according to claim 15, wherein the cryptographic key is a symmetric key that is also available to an access right generator (1) that generated the access object (21), and wherein the generating (44) comprises performing an encryption using the symmetric key.

17. The method according to claim 15, wherein the cryptographic key is a public key of a cryptographic keypair also comprising a secret key, wherein the cryptographic keypair is associated with the access right generator.

18. The method according to any one of claims 15 to 17, wherein the user identifier is in the form of a public key of a cryptographic keypair associated with the user.

19. The method according to any one of claims 15 to 17, wherein the user identifier is in the form of an e-mail address included in a certificate also comprising a public key of a cryptographic keypair associated with the user identifier forming part of a certificate for the user20. The method according to any one of claims 15 to 19, wherein the obtaining (146) the access object (21) from the user comprises receiving the access object (21) from an application executing in a user device (2) of the user (5).

21. The method according to any one of claims 15 to 20, wherein the generating (144) the validation object comprises generating the validation object based on the user identifier, the time data item, the cryptographic key and an identifier associated with the electronic lock.

22. The method according to any one of claims 15 to 21, wherein the generating (144) the validation object comprises using the user identifier, the time data item and the cryptographic key as inputs to a one-way function, and determining a personal identification number, PIN, based on the output from the one-way function.

23. The method according to claim 22, wherein the determining a PIN comprises employing a predetermined PIN extraction function on the output from the one-way function.

24. The method according to any one of claims 16 to 23 when dependent on claim 16, wherein the access object (21) comprises a cryptographic signature based on the user identifier and the time data item, and wherein the granting (148) access comprises matching the validation object against the cryptographic signature.

25. An electronic lock (12) for enabling temporary access to a physical space (16) secured by an electronic lock (12), the electronic lock (12) comprising: processing circuitry (60); and memory circuitry (64) storing instructions (67) that, when executed by the processing circuitry, cause the electronic lock (12) to: obtain a user identifier of a user (5), and a time data item defining a validity time;obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key; obtain an access object (21) from a user; and grant access to the physical space (16) based on the validation object matching the access object (21).

26. A computer program (67, 91) for enabling temporary access to a physical space (16) secured by an electronic lock (12), the computer program comprising computer program code which, when executed on an electronic lock (12) causes the electronic lock (12) to: obtain a user identifier of a user (5), and a time data item defining a validity time; obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key; obtain an access object (21) from a user; and grant access to the physical space (16) based on the validation object matching the access object (21).

27. A computer program product (64, 90) comprising a computer program according to claim 26 and a computer readable means comprising non-transitory memory in which the computer program is stored.

28. A system for enabling temporary access to a physical space (16) secured by an electronic lock (12), the system comprising an access right generator (1) and the electronic lock (12), wherein the access right generator (1) comprises: processing circuitry (60); and memory circuitry (64) storing instructions (67) that, when executed by the processing circuitry, cause the access right generator (1) to: obtain a user identifier of a user (5), and a time data item defining a validity time; obtain a cryptographic key; generate an access object (21) based on the user identifier, the time data item and the cryptographic key, to enable the electronic lock (12) to cryptographically verify the user identifier based on the access object (21); andprovide the access object (21) to the user; wherein the electronic lock (12) comprises: processing circuitry (60); and memory circuitry (64) storing instructions (67) that, when executed by the processing circuitry, cause the electronic lock (12) to: obtain the user identifier of the user (5), and a time data item defining a validity time; obtain a cryptographic key; generate a validation object based on the user identifier, the time data item and the cryptographic key; obtain the access object (21) from the user; and grant access to the physical space (16) based on the validation object matching the access object (21).

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