Use of device encryption key as basis for multi-account nearby-presence advertisement and discovery

Abstract

A method for account-specific discovery by a discoverer device that is pre-provisioned with (i) a first encryption seed, (ii) a second encryption seed, (iii) a double-encrypted metadata-encryption key (MEK), and (iv) encrypted metadata regarding an account configured on an advertiser device. The discoverer device (a) detects a broadcast advertisement message carrying an encrypted device-encryption-key (DEK) associated with the advertiser device, (b) uses the first encryption seed to decrypt the encrypted DEK and thereby to uncover the DEK, (c) maps the second encryption seed to the second encryption seed, the double-encrypted MEK, and the encrypted metadata, and (b) accordingly (i) uses the DEK and the second encryption key cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (i) uses the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

Description

Use of Device Encryption Key as Basis for Multi -Account Nearby-Presence Advertisement and DiscoveryREFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 585,464, filed September 26, 2023, the entirety of which is hereby incorporated by reference.BACKGROUND

[0002] A “nearby presence” system conveniently enables devices that are nearby each other (e.g., within wireless range of each other, or on a common network) to advertise and discover each other’s presence. For instance, an “advertiser” device may broadcast an advertisement message that advertises its presence, and a nearby “discoverer” device may detect that broadcast advertisement message and thereby discover the nearby presence of the advertiser. Once the discoverer thereby discovers the nearby presence of the advertiser, the discoverer and advertiser may then engage in further signaling to then exchange data, which may include establishing a connection with each other.

[0003] This nearby-presence system could operate with any of various wireless communication technologies, examples of which include Bluetooth, Bluetooth Low Energy (BLE), Ultra Wideband (UWB), and Wi-Fi technologies, among other possibilities. (Further, the nearby-presence system could also operate with wired communication, such as where the devices are on the same wired network as each other, among other possibilities.)

[0004] Using BLE, for instance, the advertiser may advertise its presence by repeatedly broadcasting a BLE advertisement message such as an “ADV IND” message on certain predefined BLE channels and in time slots with certain periodicity. This ADV IND message may carry an address or identifier of the advertiser and, in a legacy format, up to 37 bytes of payload data. Once the discoverer discovers broadcast of this ADV IND message, the discoverer may determine based on its received signal strength of the message (e.g., a received signal strength indicator (RSSI)) that the advertiser is nearby. In response, the discoverer may transmit a directed advertisement message to the advertiser, and the devices may exchange further information such as their respective profile and service-support information, and may then establish a direct connection with each other.SUMMARY

[0005] In some implementations, certain data carried by a nearby-presence advertisement message could be encrypted in order to help secure the data.

[0006] Without limitation, for example, an advertisement message may carry as payload an encrypted metadata encryption key (MEK) that, once decrypted, could be used to decrypt encrypted metadata regarding the advertiser, such as an encrypted instance of the name and image of an associated account holder. In practice, trusted discoverers may be preprovisioned with this encrypted metadata, perhaps by a centralized contacts server or other account server. To enable each trusted discoverer to decrypt this metadata, the advertiser and each trusted discoverer may also be pre-provisioned with an encryption seed usable as a basis to encrypt and decrypt the MEK. The advertiser may thus use that seed as a basis to encrypt the MEK so as to then include the encrypted MEK in its advertisement. Further, upon discovering such an advertisement, a trusted discoverer may use the same seed as a basis to decrypt the encrypted MEK so as to uncover the MEK, which the trusted discoverer may then use as basis to decrypt the metadata regarding the advertiser.

[0007] In some cases, an advertiser device may be configured to operate under multiple user accounts. For instance, a user’s mobile phone may have multiple user-accounts, such as a work account, a personal account, and a family account, among other examples.

[0008] When such a device is going to broadcast a nearby-presence advertisement, it may be worthwhile for the device to broadcast the advertisement specifically in relation to a particular one of those user accounts, perhaps to facilitate receipt and processing of the advertisement just by one or more discoverer devices each trusted with respect to that account in particular.

[0009] To facilitate this with the example noted above, for instance, each discoverer that is trusted with respect to that account may be pre-provisioned with encrypted metadata specific to that account (e.g., a name and image specific to that account), with that accountspecific metadata being decryptable with an MEK specific to that account. Further, the advertiser and each discoverer trusted with respect to that account may be pre-provisioned with an account-specific encryption seed usable as a basis to encrypt and decrypt that accountspecific MEK. The advertiser may thus use that account-specific seed as a basis to encrypt the account-specific MEK so as to then include the encrypted account-specific MEK in its advertisement. Further, upon discovering such an advertisement, a discoverer trusted with respect to that account may use the same account-specific seed as a basis to decrypt theencrypted account-specific MEK so as to uncover the account-specific MEK, which the trusted discoverer may then use as a basis to decrypt the account-specific metadata.

[0010] While this process may work well to facilitate nearby-presence advertising specific to a particular account, technical challenges may exist if an advertiser would seek to advertise its presence concurrently with respect to multiple accounts.

[0011] For instance, if an advertiser is configured with multiple user accounts as noted above, reason may exist for the advertiser to advertise its presence currently with respect to all of those accounts. With the process just described, however, the advertiser may not be able to do so with a single advertisement message. This is because (a) the encrypted MEK carried by that advertisement message would be specific to just one particular account, (b) the MEK would be encrypted based on a seed specific to that one particular account, (c) the MEK would function to decrypt encrypted metadata that is specific to that one particular account, and (d) discoverers that are not trusted with respect to that particular account (i) would not be pre-provisioned with the right account-specific seed, (ii) therefore could not decrypt the encrypted MEK carried by the advertisement, and (iii) even if they could uncover the account specific MEK, would not have the encrypted account-specific metadata that could be decrypted with that account-specific MEK.

[0012] In theory, some advertiser devices may be able to overcome this problem by broadcasting multiple advertisements concurrently, either using extended advertisement messaging or by transmitting separate advertisements (e.g., time division multiplexed), one advertisement per account.

[0013] With the example above, for instance, the advertiser may concurrently broadcast an advertisement message for the user’ s work account and an advertisement message for the user’s personal account. The work-account advertisement message could carry a workaccount-specific MEK encrypted based on a work-account-specific seed, and so that discoverer devices trusted with respect to that work account could use the work-account-specific seed to uncover the work-account-specific MEK and could use that work-account-specific MEK as a basis to decrypt work-account-specific metadata, such as the user’s work name and work image. Whereas, the personal-account advertisement message could carry a personal-account- specific MEK encrypted based on a personal-account-specific seed, and so that discoverer devices trusted with respect to that personal account could use the personal-account-specific seed to uncover the personal-account-specific MEK and could use that personal-account-specific MEK as a basis to decrypt personal-account-specific metadata, such as the user’s personal name and personal image.

[0014] Unfortunately, however, many devices do not support sending more than one advertisement message at a time. Further, even if a device supports sending multiple advertisement messages concurrently, doing so could be a drain on signaling and processing resources. Still further, even if a device would support sending multiple advertisement messages concurrently, the device may limit the number of such concurrent advertisement messages, perhaps allowing only up to three or five such messages at a time.

[0015] The present disclosure provides an improvement to help facilitate advertising with respect to multiple accounts concurrently in an efficient and scalable manner.

[0016] In accordance with the disclosure, an advertiser device that has multiple accounts could have a device identity that is correlated respectively with each account of its multiple accounts. When that advertiser broadcasts an advertisement message, the advertisement message will carry as payload an encrypted “device encryption key” (DEK) that is specific to the advertiser device and that, once decrypted, could be used as basis to uncover, for each account, an account-specific MEK that could in turn be used as a basis to uncover account-specific metadata.

[0017] Further, the advertiser and each discoverer trusted with respect to any one of the advertiser’s accounts may be pre-provisioned with an advertiser-device-specific encryption seed, seedo, that is usable as a basis to encrypt and decrypt that encrypted DEK. The advertiser may thus use that device-specific seedo as a basis to encrypt the device-specific DEK so as to then include the encrypted device-specific DEK in its advertisement. Upon discovering such an advertisement, a discoverer trusted with respect any one of the advertiser’s accounts may then use the same device-specific seedo as a basis to decrypt the encrypted device-specific DEK (e.g., trying each of multiple such seeds until finding that one works to decrypt the encrypted device-specific DEK), so as to uncover the device-specific DEK. The trusted discoverer may then use the uncovered device-specific DEK as a basis to access account-specific metadata as follows.

[0018] As to each given one of the advertiser’s multiple accounts, each discoverer that is trusted with respect to that given account may further be pre-provisioned, in correlation with the seedo that works to uncover that DEK, with (i) encrypted account-specific metadata for the given account, (ii) a double-encrypted account-specific MEK, which is first encryptedbased on an account-specific seed, seedA and then encrypted in a manner that can be decrypted with the advertiser’s DEK, and (iii) the account-specific seed, seedA.

[0019] When such a trusted discoverer receives the advertiser’s advertisement message that carries the encrypted DEK, the discoverer may use seedo as a basis to decrypt the encrypted DEK so as to uncover the DEK specific to the advertiser device. Further, given the seedo that worked to decrypt that encrypted DEK, the discoverer may use its pre-provisioned correlation as a basis to map the seedo to (i) the encrypted account-specific metadata for the given account, (ii) the double-encrypted MEK for the given account, and (iii) the seedA for the given account.

[0020] The discoverer may then use that DEK to engage in a first decryption of the double-encrypted account-specific MEK so as to remove one layer of encryption from the double-encrypted account-specific MEK and thereby uncovering a once-encrypted instance of the account-specific MEK. Further, the discoverer may use the account-specific seedA as a basis to decrypt the now-once-encrypted account-specific MEK, so as to uncover the accountspecific MEK. Given the account specific MEK, the discoverer may then decrypt the encrypted account-specific metadata and thus uncover the account-specific metadata.

[0021] Optimally, this process could facilitate secure and efficient advertisement and discovery concurrently with respect to multiple accounts, by just a single advertisement message from the advertiser (which the advertiser may broadcast repeatedly as noted above). Further, this process may help provide increased security and privacy, as each discoverer that receives this single advertisement message may discover just the identification information regarding the advertiser’s account that has a trust relationship with the discoverer’s account, without also discovering identification information regarding one or more other accounts of the advertiser.

[0022] For instance, if the advertiser is configured with accounts Al and A2, and if discoverers of one group are trusted as to account Al and discoverers of another group are trusted as to account A2, all of the trusted discoverers would be able to uncover the advertiser’ s DEK from the advertisement, by using seedo as a basis to decrypt the encrypted DEK. Each discoverer could then map that seedo to account-specific parameters that ultimately the discoverer to uncover account-specific metadata. In particular, each account-Al trusted discoverer could map the seedo to (i) a double-encrypted account-Al -specific MEK, (ii) an account-Al -specific seedA, and (iii) encrypted account-Al -specific metadata, and that discoverer could proceed as noted above to uncover the account-Al -specific metadata.Whereas, each account-A2 trusted discoverer could map the seedo to (i) a double-encrypted account-A2-specific MEK, (ii) an account-A2-specific seedA, and (iii) encrypted account-A2- specific metadata, and that discoverer could proceed as noted above to uncover the account- A2-specific metadata.

[0023] This process could further be scaled to potentially many accounts, with respective sets of trusted discoverers. With just a single nearby-presence advertisement, the advertiser could thereby securely advertise its presence on an account-specific basis separately to each group of applicable trusted discoverers.

[0024] Further, note that encryption seeds and encryption keys are understood in the art. For instance, an encryption seed could be a value that gets factored into a key derivation algorithm (e.g., a Hash-based Message Authentication Code (HMAC) Key Derivation Function (HKDF), among other possibilities) to dynamically produce an encryption key, such that two devices using the same encryption seed in the same algorithm as each other could produce the same encryption key as each other. An encryption key may then be a value that could be factored into a cryptographic algorithm (e.g., with symmetric key cryptography (such as Advanced Encryption Standard Counter (AES-CTR) with HMAC for message authentication), asymmetric key cryptography (such as public key cryptography), or elliptic curve cryptography, among other possibilities) to encrypt and / or decrypt input data. In alternative implementations, one or more of the encryption seeds mentioned herein may be replaced with encryption keys, and vice versa.

[0025] Accordingly, in one respect, disclosed is a method for account-specific discovery by a discoverer device that is pre-provisioned with a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device. The pre-provisioned set of data includes (i) a first encryption seed, (ii) a second encryption seed, (iii) a double-encrypted MEK, and (iv) encrypted metadata regarding the account configured on the advertiser device.

[0026] The method includes the discoverer device detecting, based on scanning of a communication channel (e.g., a wireless and / or wired communication channel), a broadcast advertisement message that carries an encrypted DEK associated with the advertiser device. Further, the method includes the discoverer device using the first encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device. Still further, the method includes the discoverer device mapping the first encryption seed to (i) the second encryption seed, (ii) the double-encrypted MEK, and (ii) the encrypted metadata. Yet further, the method includes, based on the mapping, the discoverer device (a) using the uncovered DEK and the second encryption key cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (b) using the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

[0027] In another respect, disclosed is a discoverer device having a wireless communication interface, a processor, and non-transitory data storage. The non-transitory data storage has stored thereon a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device, the set of data including (i) a first encryption seed, (ii) a second encryption seed, (iii) a double-encrypted MEK, and (iv) encrypted metadata regarding the account configured on the advertiser device. Further, the non- transitory data storage has stored thereon program instructions executable by the processor to cause the discoverer device to carry out operations for account-specific discovery.

[0028] The operations include detecting, based on scanning of a communication channel, a broadcast advertisement message that carries an encrypted DEK associated with the advertiser device. Further, the operations include using the first encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device. Still further, the operations include mapping the first encryption seed to (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata. Yet further, the operations include, based on the mapping, (a) using the uncovered DEK and the second encryption key cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (b) using the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

[0029] In yet another respect, disclosed is at least one non-transitory computer- readable medium having stored thereon program instructions executable by at least one processor of a discover device to cause the discoverer device to carry out operations such as those described above.

[0030] In still another respect, disclosed is a system that includes various means for carrying out each of the operations described herein.

[0031] These, as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings. Further, it should be understoodthat the descriptions provided in this summary and below are intended to illustrate the invention by way of example only and not by way of limitation.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure la is a simplified block diagram of an example arrangement in which various features could be implemented.

[0033] Figure lb is a simplified block diagram of another example arrangement in which various features could be implemented.

[0034] Figure 2a is a simplified block diagram illustrating example provisioning of discoverer devices.

[0035] Figure 2b is a simplified block diagram illustrating other example provisioning of discoverer devices.

[0036] Figure 3 is a flow chart illustrating an example method.

[0037] Figure 4 is a simplified block diagram of an example device.DETAILED DESCRIPTION

[0038] Example methods, devices, and systems are described herein. It should be understood, however, that any disclosed embodiment is not necessarily to be construed as preferred or advantageous over other embodiments unless stated as such. Further, it should be understood that variations from the specific arrangements and processes disclosed are possible. For instance, various disclosed entities, components, connections, operations, and other elements could be added, omitted, distributed, replicated, re-located, re-ordered, combined, or changed in other ways. In addition, it will be understood that various disclosed technical operations could be implemented at least in part by a processing unit programmed to carry out the operations or to cause one or more other entities to carry out the operations.

[0039] For sake of illustration, this description will walk through an example implementation in line with the discussion above, where an advertiser device is configured with accounts Al and A2, and where at least one discoverer device is trusted as to account Al and another discoverer device is trusted as to account A2. It will be understood, however, that the described principles could apply as well with more than two accounts, with more than one discoverer device per account, and / or with other variations.1. Example Devices, Accounts, and Trust Relationships

[0040] Referring to the drawings, as noted above, Figures la and lb illustrate example arrangements in which various disclosed features could be implemented. The illustrated examples include devices shown as an advertiser 100, a first discoverer 102, and a second discoverer 104.

[0041] The arrangement shown in Figure la is an example of a “same account” implementation. In this example arrangement, account Al is configured on both the advertiser 100 and the first discoverer 102, and account A2 is configured on both the advertiser 100 and the second discoverer 104.

[0042] Without limitation, this same-account implementation could be where a given user has accounts Al and A2 and owns and operates three devices, and where accounts Al and A2 are both configured on one device, just account Al is configured on another device, and just account A2 is configured on the remaining device. In this situation, two separate instances of the same account may implicitly have a trust relationship with each other, as they are the same account; for instance, the user’s account Al on one device has a trust relationship with the user’s account Al on another device, and the user’s account A2 on one device has a trust relationship with the user’s same account At on another device. Whereas, the user’s account Al on one device may not have a trust relationship with the user’s account A2 on another device.

[0043] This same-account implementation may optimally enable the user’s devices to discover each other’ s nearby presence in an account-specific manner. For instance, when the user brings a first one of the user’s devices near both of the user’s other devices, the user’s first device may broadcast a single advertisement message, and each of the user’s other devices may discover that advertisement message and responsively uncover and present account-specific metadata just as to the account that the other device has in common with the first device.

[0044] The arrangement shown in Figure lb, on the other hand, is an example of a “known contact” implementation. In this example arrangement, a first user’s accounts Al and A2 may be configured on one device, a second user’s account having a trust relationship with the first user’s account Al may be configured on another device, and a third user’s account having a trust relationship with the first user’s account A2 may be configured on yet another device.

[0045] Without limitation, this known-contact implementation could be where each user owns and operates a respective device configured with the applicable account(s) (e.g., thefirst user owns and operates a device configured with the first user’s accounts Al and A2, the second user owns and operates a device configured with the second user’s account, and third user owns and operates a device configured with the third user’ s account), and where applicable trust relationships are established between these accounts.

[0046] These trust relationships could be established in various ways and could be unidirectional or bidirectional.

[0047] By way of example, a trust relationship that gives a first user the right to discover a device configured under a second user’s account could be established by listing the first user’s account in a contact list of the second user’s account, and engaging in associated provisioning.

[0048] For instance, the first user may establish a trust relationship between the first user’s account Al and the second user’s account by adding an entry for the second user’s account to a contact list defined for the first user’s account Al. The first user’s addition of this contact entry may in turn cause the first user’s device to synchronize this trust relationship with an account server, and the account server may in turn provision the second user’s device with data that enables the second user’s device to discover nearby presence of the first user’s device under the first user’s account Al in particular.

[0049] Likewise, the first user may establish a trust relationship between the first user’s account A2 and the third user’s account by adding an entry for the third user’s account to a contact list defined for the first user’s account A2. The first user’s addition of this contact entry may then similarly cause the first user’s device to synchronize this trust relationship with the account server (or another account server), and the account server may then similarly provision the third user’s device with data that enables the third user’s device to discover nearby presence of the first user’s device under the first user’s account A2 in particular.

[0050] As another example, a trust relationship could be established between one user’s device and another user’s device by scanning a quick-response (QR) code or the like. For instance, the first user’s device under the first user’s account Al may have an associated QR code that the second user’s device operating under the second user’s account could scan, and this scanning may cause the second user’s device to engage in signaling with an account server to become provisioned with data that enables the second user’ s device to discover nearby presence of the first user’s device under the first user’s account Al. As a specific example of this, a first user having a party may provide a QR code that guests’ devices could scan in orderto establish a trust relationship with a particular account configured on the first user’s devices and to then be able to discover the first user’s devices under that account.

[0051] The devices shown in Figures la and lb could each take any of a variety of forms and may differ in form from each other. Without limitation, for instance, each device could be a user-operated device such as a mobile phone, a tablet, a laptop, a wearable device, a gaming device, or a combination of these and / or other devices. Each device may thus be owned and / or operated by, or otherwise be associated with, a respective user.

[0052] As shown in Figure la, for instance, the advertiser 100, the first discoverer 102, and the discoverer 104 may be owned and / or operated by a common user Ul. Whereas, as shown in Figure lb, the advertiser 100 may be owned and / or operated by a user Ul, the first discoverer 102 may be owned and / or operated by a user U2 and the second discoverer 104 may be owned and / or operated by a user U3. Other arrangements may be possible as well.

[0053] Each of these devices may be configured to operate under one or more accounts associated with its user. Each account may define a respective operational profile, which may be for the device generally or for one or more applications on the device, including account-specific settings and account-specific data at the device, among other possibilities. Further, each account may be registered with an account server, which may also store the account settings and data and may facilitate backup, syncing, and other management of the account.

[0054] An example account associated with a user and configured on the user’s device may have a respective set of metadata, such as a name of the user, a description of the user, and an image associated with the user, and this metadata may be the same or different per account of the user. The account server and device may store this metadata in association with the user’s account, as characteristic information about the account for instance.

[0055] Further, an example account associated with a user and configured on the user’s device may have other associated settings and data. Without limitation, this may include an associated set of personal-information-management (PIM) data such as contacts, calendar, email history, chat history, and / or other account-specific information. In addition, this may include other account-specific information, such as photos, videos, documents, and application-settings, among other possibilities.

[0056] Configuring the device to operate under a given account may involve the user signing into the account or otherwise selecting the account on the device, which may render the selected account an active account defining an associated operational profile on thedevice. Further, signing into or otherwise selecting a given account on the device may also include logging in to the account at the account server, through a communication link between the device and the account server, which may also trigger synchronizing of account settings and data between the device and the account server.

[0057] For instance, an operating system or application on the device may provide an interface through which the user could log in to a desired account by entering accountspecific security credentials. Through a network communication link between the device and the account server, the account server may then receive these security credentials and authenticate the user, allowing the login to proceed. Upon user login to a given account and / or at other times, the account server and device may also synchronize account information such as account-specific settings and data with each other, so that the device would become provisioned with up-to-date account settings and data, such as with up-to-date account-specific metadata and PIM data for instance.

[0058] A device may be configured to operate under multiple accounts at once. For instance, a user may log into multiple separate accounts on the device. As a result, the device may thus have a composite operational profile including account-specific settings and accountspecific data cooperatively of the multiple accounts. Alternatively or additionally, the device may allow the user to switch between logged-in accounts in order to access and make use of the settings and data associated with one account or another as desired.

[0059] In an example implementation, a user may have work and personal accounts, and the user’s device may be configured to operate under either or each of these accounts. Each of these accounts as registered at the account server and as configured on the user’ s device may store and / or otherwise have associated account-specific metadata and other data as noted above, which may differ per account. For instance, the user’s work account may have a relatively formal name and profile image of the user along with the user’s work title and other such information, as well as work-related PIM information of the user. Whereas, the user’s personal account may have a relatively informal name (e.g., nickname) and informal image of the user, along with one or more other personal descriptors of the user, as well as personal PIM information of the user.2. Example Same-Account Implementation

[0060] In the example arrangement of Figure la, as noted above, the advertiser 100, first discoverer 102, and second discoverer 104 may all be devices of the same user Ul. The advertiser 100 may operate under both a work account of user Ul and a personal account ofuser Ul , the first discoverer 102 may operate under the work account of user U 1 , and the second discoverer 104 may operate under the personal account of user Ul.

[0061] As noted above, two instances of the same account may implicitly have a trust relationship with each other. Thus, two devices that are configured to operate under the same account as each other may have an associated trust relationship with each other keyed to that common account. Among other possibilities, this trust relationship may define a right of each instance of the account to discover nearby presence of a device that also operates under the same account and to access associated metadata (e.g., user name, description, and image) of the account. Further, a trust relationship between instances of a common account may define different or other associated rights.

[0062] This trust relationship between two instances of the same account may be established implicitly and by the devices synchronizing with an account server. Without limitation, when devices have a trust relationship with each other keyed to a common account, the devices may each store data regarding that common account, such as the encryption seeds and associated information noted above for use in the present process. For instance, the account server may pre-provision each device in the trust relationship with this information.

[0063] In line with the discussion above, the present process could enable the advertiser 100 to securely advertise its presence concurrently under both the work account of user Ul and the personal account of user Ul, so as to allow the first discoverer 102 and the second discoverer 104 to each detect and respond to nearby presence of the advertiser 100 with respect to those different accounts of user Ul. In particular, the present process could involve the advertiser 100 broadcasting an advertisement message 106 that the first discoverer 102 would treat as an advertisement from the advertiser 100 under the work account of user U 1 and that the second discoverer 104 would treat as an advertisement from the advertiser 100 under the personal account of user U 1.

[0064] Figure 2a illustrates example provisioning of the first discoverer 102 and the second discoverer 104, with information to facilitate this process in the same-account context of Figure la. Namely, Figure 2a illustrates how an account server 108 may pre-provision the first discoverer 102 and the second discoverer 104 with this information, based on the sameaccount trust relationships between the devices’ respective accounts. The account server 108 may provision the devices with this information at the time user Ul logs in to the account respectively on each device and / or at other times. The account server 108 may do so by transmitting the information over network connections to the devices and having the devicesreceive and store the transmitted information for later use. Other methods for pre-provisioning the devices with this information may be possible as well, whether or not involving an account server.

[0065] As shown in Figure 2a, in order to enable the account server 108 to provision the first discoverer 102 and second discoverer 104 with a DEK that is specific to the advertiser 100 and with an encryption seedo that the advertiser 100 would use as a basis to encrypt that advertiser-specific DEK, the advertiser 100 may generate these values of DEK and seedo and send the values to the account server 108. Alternatively, the account server 108 may generate these values for the advertiser 100 and may send these values to the advertiser 100. Further, the advertiser 100 may store this DEK and seedo for later use when the advertiser 100 would transmit an advertisement message such as message 106.

[0066] The advertiser-specific DEK may be an encryption key that could be used as a basis to decrypt metadata of each of the accounts under which the advertiser 100 operates, namely, the work account of user U1 and the personal account of user U1 in the present example. The encryption seedo may be a pseudo-random-number-generator seed or the like, which the advertiser 100 could use as a basis to dynamically generate an encryption key that the advertiser 100 could then use to encrypt the advertiser-specific DEK.

[0067] Further, in order to enable the first discoverer 102 and second discoverer 104 to treat advertisement message 106 differently than each other based on their respective account-specific trust relationships with the advertiser 100, the account server 108 may provision the first discoverer 102 and the second discoverer 104 with separate respective sets of information usable by each discoverer accordingly.

[0068] As shown in Figure 2a, for instance, the account server 108 may provision the first discoverer 102 with a set of information based on the trust relationship between the advertiser 100 and the first discoverer 102, namely based on the trust relationship between the work account of user U1 on the advertiser 100 and the same work account of user U1 on the discoverer 102. This information can include device-level information associated with the advertiser 100 and related account-level information associated with the work account of user U1 in particular.

[0069] The device-level information that gets provisioned into the first discoverer 102 can include the same seedo noted above, which the first discoverer 102 could use as a basis to decrypt the encrypted advertiser-specific DEK carried in the advertisement message 106 from the advertiser 100. For instance, the first discoverer 102 may use this seedo in the samemanner as the advertiser 100, to correspondingly generate the same encryption key that the advertiser 100 would use as a basis to encrypt the DEK, and the first discoverer 102 may use that generated encryption key as a basis to decrypt the encrypted DEK.

[0070] The account-level information that gets provisioned into the first discoverer device 102 can be provisioned in a data relationship with this device-level information (e.g., as related to seedo), and the first discoverer 102 could accordingly store this account-level information as being related to that device-level information. That way, the first discoverer 102 may be able to retrieve the account-level information based on the first discoverer 102 receiving the advertisement message 106 and determining that the device-level information facilitates decrypting the encrypted DEK in that advertisement message 106.

[0071] In line with the discussion above, the account-level information that gets provisioned into the first discoverer device 102 could include an encrypted copy of the accountspecific metadata of the work account of user U 1. Namely, this can include the account-specific metadata of the work account of user U1 encrypted with an MEK that is specific to that work account of user Ul. For instance, if the account-specific metadata of the work account of user U1 includes the formal name and formal image of user Ul and a work description of user Ul, the account server 108 may establish this MEK-encrypted copy of that work-account metadata by grouping the metadata together and using the account-specific MEK as a basis to encrypt that group of metadata.

[0072] In addition, the account-level information that gets provisioned into the first discoverer device 102 could include a double-encrypted copy of the account-specific MEK, namely, of the MEK that is useable as a basis to decrypt the MEK-encrypted copy of the account-specific metadata of the work account of user Ul. This MEK could be the same MEK used to encrypt the account-specific metadata of the work account of user Ul. The account server 108 could double-encrypt this MEK by imposing (i) a layer of encryption specific to the work account of user Ul and (ii) a second layer of encryption specific to the advertiser device 100. For instance, the account server 108 could first encrypt this MEK based on an accountspecific seedA that is specific to the work account of user Ul (e.g., using that account-specific seedA as a basis to dynamically generate an encryption key and using that generated encryption key as a basis to encrypt the MEK), so as to establish a single-encrypted MEK. Then the account server 108 could encrypt that single-encrypted MEK using the DEK specific to the advertiser 100, so as to establish the double-encrypted MEK specific to the work account of user Ul.

[0073] Further, the account-level information that gets provisioned into the first discoverer device 102 could also include the seedA that is specific to the work account of user Ul. Given this seedA specific to the work account of user Ul, and given the DEK specific to the advertiser 100, the first discoverer 102 may thereby uncover the MEK specific to the work account of user Ul. For instance, the first discoverer 102 may use the advertiser-specific DEK as a basis to engage in a first decryption of the double-encrypted MEK specific to the work account of user Ul, so as to uncover a once-encrypted instance of the account-specific MEK. Then the first discoverer 102 may use this seedA in the same manner as the account server 108, to correspondingly generate the same encryption key that the account server used as a basis to encrypt the MEK specific to the work account of user Ul, and the first discoverer 102 may use that generated encryption key as a basis to decrypt the once-encrypted account-specific MEK, so as to thereby uncover the MEK specific to the work account of user U 1.

[0074] In an alternative implementation, because the advertiser 100 and the first discoverer 102 are operating under the same work account of user Ul as each other, the account server 108 may provision each of these devices with the above account-level information as to that work account, and each device may store that account-level information in data- relationship with the device-level information of each other device of the user Ul as indicated by the account server 108 for instance.

[0075] Given this device-level information associated with advertiser 100 and the related account-level information associated with the work account of user Ul, the first discoverer 102 could thereby treat the advertisement message 106 from the advertiser 100 as being an advertisement message under the work account of user Ul.

[0076] For instance, once the first discoverer 102 detects this advertisement message 106 (e.g., through scanning on a predefined wireless channel), the first discoverer 102 may search through one or more instances of seedo pre-provisioned in the first discoverer 102 and may identify the pre-provisioned seedo that works as a basis to decrypt the encrypted DEK carried by the advertisement message 106. The first discoverer 102 may thereby uncover the DEK associated with the advertiser 100. Further, the first discoverer 102 may map the identified seedo to the pre-provisioned work-account information of user Ul as noted above, including (i) the MEK-encrypted copy of the account-specific metadata of the work account of user Ul, (ii) the double-encrypted MEK specific to the work account of user Ul, and (iii) the seedA specific to the work account of user U 1.

[0077] As discussed above, the first discoverer 102 may then double-decrypt the double-encrypted MEK, first using the DEK specific to the advertiser 100 and then using the seedA specific to the work account of user Ul, thereby uncovering the MEK specific to the work account of the user Ul. Then the first discoverer 102 may use this MEK specific to the work account of user Ul as a basis to decrypt the encrypted account-specific metadata of the work account of user U 1.

[0078] Through this process, the first discoverer 102 may thereby uncover the account-specific metadata of the work account of user Ul, and the first discoverer 102 may make use of that uncovered work-account metadata to make its nearby-presence detection specific to the work account of user U 1.

[0079] For instance, the first discoverer 102 may present this uncovered workaccount metadata in connection with a prompt requesting user Ul to approve establishment of a data session between the advertiser 100 and the first discoverer 102. Upon receipt of approval from user Ul in response to this prompt, the first discoverer 102 may then send an advertisement response message to the advertiser 100, and the advertiser 100 and first discoverer 102 may work to establish a data session with each other through which they may then exchange useful information with each other. (Alternatively, the prompt and associated process may be to share information with each other, such as to share one or more images, or other data with each other, among other possibilities.)

[0080] Through this example process, even though the advertisement message 106 broadcast by the advertiser 100 may have carried just device-specific information (e.g., the encrypted DEK specific to the advertiser 100) and possibly no account-specific information, the advertisement message 106 can come across at the first discoverer 102 as being an advertisement message from the advertiser 100 specifically under the work account of user U 1. As a result, the first discoverer 102 is still able to treat the advertisement message 106 as being an advertisement message from the advertiser 100 specifically under the work account of user Ul. For instance, the prompt that the first discoverer 102 presents to user Ul in the example above can still be customized to the work account of user Ul, e.g., showing the formal name and formal image of user Ul and the work description of user Ul. This process can thus conveniently support the work-related trust relationship between the user’s work account on the advertiser 100 and the user’s same work account on the first discoverer 102.

[0081] Continuing with reference to Figure 2a, the account server 108 may provision the second discoverer 104, on the other hand, with a set of information based on atrust relationship between the personal account of user U1 on the advertiser 100 and the same personal account of user U1 on the discoverer 102. This information can include device-level information associated with the advertiser 100 and related account-level information associated with the personal account of user U1 in particular.

[0082] The device-level information that gets provisioned into the second discoverer 104 can include the same advertiser-specific seedo noted above, which the second discoverer 104 could likewise use as a basis to decrypt the encrypted advertiser-specific DEK carried in the advertisement message 106 from the advertiser. For instance, the second discoverer 104 may likewise use this seedo in the same manner as the advertiser 100, to correspondingly generate the same encryption key that the advertiser 100 would use as a basis to encrypt the DEK, and the second discoverer 104 may use that generated encryption key as a basis to decrypt the encrypted DEK.

[0083] The account-level information that gets provisioned into the second discoverer device 104 can also be provisioned in a data relationship with this device-level information (e.g., as related to seedo), and the second discoverer 104 could accordingly store this account-level information as being related to that device-level information. That way, the second discoverer 104 may be able to retrieve the account-level information based on the second discoverer 102 receiving the advertisement message 106 and determining that the device-level information facilitates decrypting the encrypted DEK in that advertisement message 106.

[0084] In this case, however, the account-level information that gets provisioned into the second discoverer device 104 could include an encrypted copy of the account-specific metadata of the personal account of user Ul. Namely, this can include the account-specific metadata of the personal account of user Ul encrypted with an MEK that is specific to that personal account of user Ul. For instance, if the account-specific metadata of the personal account of user Ul includes the casual name (e.g., nickname) and casual image of user Ul and a personal description of user Ul, the account server 108 may establish this MEK-encrypted copy of that personal-account metadata by grouping the metadata together and using the account-specific MEK as a basis to encrypt that group of metadata.

[0085] In addition, the account-level information that gets provisioned into the second discoverer device 104 could include a double-encrypted copy of the account-specific MEK, namely, of the MEK that is useable as a basis to decrypt the MEK-encrypted copy of the account-specific metadata of the personal account of user Ul. This MEK could be the sameMEK used to encrypt the account-specific metadata of the personal account of user Ul. By analogy here, the account server 108 could double-encrypt this MEK by imposing (i) a layer of encryption specific to the personal account of user Ul and (ii) a second layer of encryption specific to the advertiser device 100. For instance, the account server 108 could first encrypt this MEK based on an account-specific seed \ that is specific to the personal account of user Ul (e.g., using that account-specific seed \ as a basis to dynamically generate an encryption key and using that generated encryption key as a basis to encrypt the MEK), so as to establish a single-encrypted MEK. Then the account server 108 could encrypt that single-encrypted MEK using the DEK specific to the advertiser 100, so as to establish the double-encrypted MEK specific to the personal account of user Ul.

[0086] Further, the account-level information that gets provisioned into the second discoverer device 104 could include the seed \ that is specific to the personal account of user Ul. Given this seed \ specific to the personal account of user Ul, and given the DEK specific to the advertiser 100, the second discoverer 104 may thereby uncover the MEK specific to the personal account of user Ul. For instance, the second discoverer 104 may use the advertiserspecific DEK as a basis to engage in a first decryption of the double-encrypted MEK specific to the personal account of user Ul, so as to uncover a once-encrypted instance of the accountspecific MEK. Then the second discoverer 104 may use this seed \ in the same manner as the account server 108, to correspondingly generate the same encryption key that the account server used as a basis to encrypt the MEK specific to the personal account of user Ul, and the second discoverer 104 may use that generated encryption key as a basis to decrypt the once- encrypted account-specific MEK, so as to thereby uncover the MEK specific to the personal account of user U 1.

[0087] In an alternative implementation, because the advertiser 100 and the second discoverer 104 are operating under the same personal account of user Ul as each other, the account server 108 may provision each of these devices with the above account-level information as to that personal account, and each device may store that account-level information in data-relationship with the device-level information of each other device of the user Ul as indicated by the account server 108 for instance.

[0088] Given this device-level information associated with advertiser 100 and the related account-level information associated with the personal account of user Ul, the second discoverer 104 could thereby treat the advertisement message 106 from the advertiser 100 as being an advertisement message under the personal account of user Ul, while the first discover102 treats the very same advertisement message 106 from the advertiser 100 as being an advertisement message under the work account of user Ul. As noted above, this arrangement may help to support improved privacy, as each discoverer may gain no information about the user’s other account as to which it does not have a trust relationship.

[0089] For instance, once the second discoverer 104 detects this advertisement message 106 (e.g., through scanning on a predefined wireless channel), the second discoverer 104 may search through one or more instances of seedo pre-provisioned in the second discoverer 104 and may likewise identify the pre-provisioned seedo that works as a basis to decrypt the encrypted DEK carried by the advertisement message 106. The second discoverer 104 may likewise thereby uncover the DEK associated with the advertiser 100. However, rather than mapping the identified seedo to the work-account related information of user Ul as the first discoverer 102 does, the second discoverer 104 may map the identified seedo to the preprovisioned personal-account related information of user Ul. For instance, the second discoverer 104 may map the identified seedo to (i) the MEK-encrypted copy of the accountspecific metadata of the personal account of user Ul, (ii) the double-encrypted MEK specific to the personal account of user Ul, and (iii) the seedA specific to the personal account of user Ul.

[0090] As discussed above, the second discoverer 104 may then likewise doubledecrypt the double-encrypted MEK, first using the DEK specific to the advertiser 100 and then using the seedA specific to the personal account of user Ul, thereby uncovering the MEK specific to the personal account of the user Ul. Then the second discoverer 104 may use this MEK specific to the personal account of user Ul as a basis to decrypt the encrypted accountspecific metadata of the personal account of user Ul.

[0091] Through this process, the second discoverer 104 may thereby uncover the account-specific metadata of the personal account of user Ul, and the second discoverer 104 may make use of that uncovered personal-account metadata to make its nearby-presence detection specific to the personal account of user Ul.

[0092] For instance, the second discoverer 104 may present this uncovered personal-account metadata in connection with a prompt requesting user Ul to approve establishment of a data session between the advertiser 100 and the second discoverer 104. Upon receipt of approval from user Ul in response to this prompt, the second discoverer 104 may then send an advertisement response message to the advertiser 100, and the advertiser 100 and second discoverer 104 may work to establish a data session with each other through whichthey may then exchange useful information with each other. (Alternatively, the prompt and associated process may be to share information with each other, such as to share one or more images, or other data with each other, among other possibilities.)

[0093] Accordingly, with this further example process, even though the advertisement message 106 broadcast by the advertiser 100 may have carried just devicespecific information and possibly no account-specific information, the advertisement message 106 (i) can come across at the first discoverer 102 as being an advertisement message from the advertiser 100 specifically under the work account of user U1 and (ii) can come across at the second discoverer 104 as being an advertisement message from the advertiser 100 specifically under the personal account of user U 1.

[0094] Conveniently, the advertiser 100 may thereby achieve multi-account advertisement without a need to separately send an advertisement message respectively under each account. This may thereby help conserve communication resources, processing resources, and power resources at the advertiser. Furthermore, as noted above, this process may optimally scale non-linearly to any number of accounts. For instance, if an advertiser operates under five separate accounts and each account has a trust relationship with a respective discoverer, the advertiser may be able to use the present process to efficiently broadcast a device-specific advertisement message and have each discoverer securely uncover and present the user account metadata applicable to its respective trust relationship, which may thereby facilitate accountspecific nearby-presence processing among other benefits.3. Example Known-Contact Implementation

[0095] In the example arrangement of Figure lb, the advertiser 100 may operate under both a work account of user U1 and a personal account of user Ul, the first discoverer 102 may operate under a work account of user U2, and the second discoverer 104 may operate under a personal account of user U3.

[0096] These accounts may also have certain defined trust relationships with each other, and the devices may thus have associated trust relationships with each other keyed to the accounts under which the devices operate. Among other possibilities, a trust relationship between accounts may define a right under one account to access certain information associated with another account. For instance, a trust relationship between accounts may define a right under one account to access the account metadata (e.g., user name, description, and image) of the other account. Further, a trust relationship between accounts may define different or other associated rights.

[0097] These trust relationships may be established by the users of the devices and / or by administrative policies and input. Further, as with other account settings and data, information about these trust relationships may be stored at an account server and may be synchronized and / or otherwise provisioned at the applicable devices.

[0098] Without limitation, when devices have a trust relationship with each other keyed their respective accounts, the devices may each store data regarding each other, such as the encryption seeds and associated information noted above for use in the present process. For instance, the account server may pre-provision each device in the trust relationship with this information. Each device in a trust relationship with another device may store this information about the other device within or in association with a contact record for the other device, to enable convenient access to the information.

[0099] In an example implementation, users U1 and U2 may work at the same company as each other, and their respective work accounts may be registered with a common account server and have a trust relationship with each other. This trust relationship, as configured on the advertiser 100 and first discoverer 102, may be established by administrative policy at the users’ company and / or through input or configuration by the users themselves. Pursuant to this trust relationship, the advertiser 100 may be pre-provisioned with applicable data regarding the first discoverer 102 to facilitate the present process, and the first discoverer 102 may be pre-provisioned with applicable data regarding the advertiser 100 to facilitate the present process.

[0100] Further, users U1 and U3 may be personal friends with each other, and their respective personal accounts may be registered with a common account server, possibly the same account server that handles the work accounts of users U 1 and U2. This trust relationship, as configured on the advertiser 100 and first discoverer 102, may be established by input or configuration by the users themselves, such as by the users establishing respective contact entries for each other for instance. Pursuant to this trust relationship, the advertiser 100 may be pre-provisioned with applicable data regarding the second discoverer 104 to facilitate the present process, and the second discoverer 104 may be pre-provisioned with applicable data regarding the advertiser 100 to facilitate the present process.

[0101] In line with the discussion above, the present process could enable the advertiser 100 to securely advertise its presence concurrently under both the work account of user U1 and the personal account of user Ul, so as to allow the first discoverer 102 and the second discoverer 104 to each detect and respond to nearby presence of the advertiser 100 withrespect to those different accounts of user Ul. In particular, the present process could involve the advertiser 100 broadcasting an advertisement message 106 that the first discoverer 102 would treat as an advertisement from the advertiser 100 under the work account of user U 1 and that the second discoverer 104 would treat as an advertisement from the advertiser 100 under the personal account of user U 1.

[0102] Figure 2b illustrates example provisioning of the first discoverer 102 and the second discoverer 104 with information to facilitate this process. Namely, Figure 2b illustrates how an account server 108 may pre-provision the first discoverer 102 and the second discoverer 104 with this information, based on the trust relationships between the devices’ respective accounts. The account server 108 may provision the devices with this information at the time the users log in to the respective accounts and / or at other times. The account server 108 may do so by transmitting the information over network connections to the devices and having the devices receive and store the transmitted information for later use. Other methods for pre-provisioning the devices with this information may be possible as well, whether or not involving an account server.

[0103] As shown in Figure 2b, in order to enable the account server 108 to provision the first discoverer 102 and second discoverer 104 with a DEK that is specific to the advertiser 100 and with an encryption seedo that the advertiser 100 would use as a basis to encrypt that advertiser-specific DEK, the advertiser 100 may generate these values of DEK and seedo and send the values to the account server 108. Alternatively, the account server 108 may generate these values for the advertiser 100 and may send these values to the advertiser 100. Further, the advertiser 100 may store this DEK and seedo for later use when the advertiser 100 would transmit an advertisement message such as message 106.

[0104] The advertiser-specific DEK may be an encryption key that could be used as a basis to decrypt metadata of each of the accounts under which the advertiser 100 operates, namely, the work account of user Ul and the personal account of user Ul in the present example. The encryption seedo may be a pseudo-random-number-generator seed or the like, which the advertiser 100 could use as a basis to dynamically generate an encryption key that the advertiser 100 could then use to encrypt the advertiser-specific DEK.

[0105] Further, in order to enable the first discoverer 102 and second discoverer 104 to treat advertisement message 106 differently than each other based on their respective trust relationships with the advertiser 100, the account server 108 may provision the firstdiscoverer 102 and the second discoverer 104 with separate respective sets of information usable by each discoverer accordingly.

[0106] As shown in Figure 2b, for instance, the account server 108 may provision the first discoverer 102 with a set of information based on the trust relationship between the advertiser 100 and the first discoverer 102, namely based on the trust relationship between the work account of user U 1 and the work account of user U2. This information can include devicelevel information associated with the advertiser 100 and related account-level information associated with the work account of user U1 in particular.

[0107] The device-level information that gets provisioned into the first discoverer 102 can include the same seedo noted above, which the first discoverer 102 could use as a basis to decrypt the encrypted advertiser-specific DEK carried in the advertisement message 106 from the advertiser. For instance, the first discoverer 102 may use this seedo in the same manner as the advertiser 100, to correspondingly generate the same encryption key that the advertiser 100 would use as a basis to encrypt the DEK, and the first discoverer 102 may use that generated encryption key as a basis to decrypt the encrypted DEK.

[0108] The account-level information that gets provisioned into the first discoverer device 102 can be provisioned in a data relationship with this device-level information (e.g., as related to seedo), and the first discoverer 102 could accordingly store this account-level information as being related to that device-level information. That way, the first discoverer 102 may be able to retrieve the account-level information based on the first discoverer 102 receiving the advertisement message 106 and determining that the device-level information facilitates decrypting the encrypted DEK in that advertisement message 106.

[0109] In line with the discussion above, the account-level information that gets provisioned into the first discoverer device 102 could include an encrypted copy of the accountspecific metadata of the work account of user U 1. Namely, this can include the account-specific metadata of the work account of user U1 encrypted with an MEK that is specific to that work account of user Ul. For instance, if the account-specific metadata of the work account of user U1 includes the formal name and formal image of user Ul and a work description of user Ul, the account server 108 may establish this MEK-encrypted copy of that work-account metadata by grouping the metadata together and using the account-specific MEK as a basis to encrypt that group of metadata.

[0110] In addition, the account-level information that gets provisioned into the first discoverer device 102 could include a double-encrypted copy of the account-specific MEK,namely, of the MEK that is useable as a basis to decrypt the MEK-encrypted copy of the account-specific metadata of the work account of user Ul. This MEK could be the same MEK used to encrypt the account-specific metadata of the work account of user Ul. The account server 108 could double-encrypt this MEK by imposing (i) a layer of encryption specific to the work account of user Ul and (ii) a second layer of encryption specific to the advertiser device 100. For instance, the account server 108 could first encrypt this MEK based on an accountspecific seedA that is specific to the work account of user Ul (e.g., using that account-specific seedA as a basis to dynamically generate an encryption key and using that generated encryption key as a basis to encrypt the MEK), so as to establish a single-encrypted MEK. Then the account server 108 could encrypt that single-encrypted MEK using the DEK specific to the advertiser 100, so as to establish the double-encrypted MEK specific to the work account of user Ul.

[0111] Further, the account-level information that gets provisioned into the first discoverer device 102 could also include the seedA that is specific to the work account of user Ul. Given this seedA specific to the work account of user Ul, and given the DEK specific to the advertiser 100, the first discoverer 102 may thereby uncover the MEK specific to the work account of user Ul. For instance, the first discoverer 102 may use the advertiser-specific DEK as a basis to engage in a first decryption of the double-encrypted MEK specific to the work account of user Ul, so as to uncover a once-encrypted instance of the account-specific MEK. Then the first discoverer 102 may use this seedA in the same manner as the account server 108, to correspondingly generate the same encryption key that the account server used as a basis to encrypt the MEK specific to the work account of user Ul, and the first discoverer 102 may use that generated encryption key as a basis to decrypt the once-encrypted account-specific MEK, so as to thereby uncover the MEK specific to the work account of user U 1.

[0112] Given this device-level information associated with advertiser 100 and the related account-level information associated with the work account of user Ul, the first discoverer 102 could thereby treat the advertisement message 106 from the advertiser 100 as being an advertisement message under the work account of user Ul.

[0113] For instance, once the first discoverer 102 detects this advertisement message 106 (e.g., through scanning on a predefined wireless channel), the first discoverer 102 may search through one or more instances of seedo pre-provisioned in the first discoverer 102 and may identify the pre-provisioned seedo that works as a basis to decrypt the encrypted DEK carried by the advertisement message 106. The first discoverer 102 may thereby uncover theDEK associated with the advertiser 100. Further, the first discoverer 102 may map the identified seedo to the pre-provisioned work-account information of user U1 as noted above, including (i) the MEK-encrypted copy of the account-specific metadata of the work account of user Ul, (ii) the double-encrypted MEK specific to the work account of user Ul, and (iii) the seedA specific to the work account of user U 1.

[0114] As discussed above, the first discoverer 102 may then double-decrypt the double-encrypted MEK, first using the DEK specific to the advertiser 100 and then using the seedA specific to the work account of user Ul, thereby uncovering the MEK specific to the work account of the user Ul. Then the first discoverer 102 may use this MEK specific to the work account of user Ul as a basis to decrypt the encrypted account-specific metadata of the work account of user U 1.

[0115] Through this process, the first discoverer 102 may thereby uncover the account-specific metadata of the work account of user Ul, and the first discoverer 102 may make use of that uncovered work-account metadata to make its nearby-presence detection specific to the work account of user U 1.

[0116] For instance, the first discoverer 102 may present this uncovered workaccount metadata to user U2 in connection with a prompt requesting user U2 to approve establishment of a data session between the advertiser 100 and the first discoverer 102. Upon receipt of approval from user U2 in response to this prompt, the first discoverer 102 may then send an advertisement response message to the advertiser 100, and the advertiser 100 and first discoverer 102 may work to establish a data session with each other through which they may then exchange useful information with each other. (Alternatively, the prompt and associated process may be to share information with each other, such as to share one or more images, or other data with each other, among other possibilities.)

[0117] Through this example process, even though the advertisement message 106 broadcast by the advertiser 100 may have carried just device-specific information (e.g., the encrypted DEK specific to the advertiser 100) and possibly no account-specific information, the advertisement message 106 can come across at the first discoverer 102 as being an advertisement message from the advertiser 100 specifically under the work account of user U 1. As a result, the first discoverer 102 is still able to treat the advertisement message 106 as being an advertisement message from the advertiser 100 specifically under the work account of user Ul. For instance, the prompt that the first discoverer 102 presents to user U2 in the example above can still be customized to the work account of user Ul, e.g., showing the formal nameand formal image of user U1 and the work description of user Ul. This process can thus conveniently support the work-related trust relationship between user Ul and user U2.

[0118] Continuing with reference to Figure 2b, the account server 108 may provision the second discoverer 104, on the other hand, with a set of information based on the trust relationship between the advertiser 100 and the second discoverer, namely, based on the trust relationship between the personal account of user U 1 and the personal account of user U3. This information can include device-level information associated with the advertiser 100 and related account-level information associated with the personal account of user Ul in particular.

[0119] The device-level information that gets provisioned into the second discoverer 104 can include the same advertiser-specific seedo noted above, which the second discoverer 104 could likewise use as a basis to decrypt the encrypted advertiser-specific DEK carried in the advertisement message 106 from the advertiser. For instance, the second discoverer 104 may likewise use this seedo in the same manner as the advertiser 100, to correspondingly generate the same encryption key that the advertiser 100 would use as a basis to encrypt the DEK, and the second discoverer 104 may use that generated encryption key as a basis to decrypt the encrypted DEK.

[0120] The account-level information that gets provisioned into the second discoverer device 104 can also be provisioned in a data relationship with this device-level information (e.g., as related to seedo), and the second discoverer 104 could accordingly store this account-level information as being related to that device-level information. That way, the second discoverer 104 may be able to retrieve the account-level information based on the second discoverer 102 receiving the advertisement message 106 and determining that the device-level information facilitates decrypting the encrypted DEK in that advertisement message 106.

[0121] In this case, however, the account-level information that gets provisioned into the second discoverer device 104 could include an encrypted copy of the account-specific metadata of the personal account of user Ul. Namely, this can include the account-specific metadata of the personal account of user Ul encrypted with an MEK that is specific to that personal account of user Ul. For instance, if the account-specific metadata of the personal account of user Ul includes the casual name (e.g., nickname) and casual image of user Ul and a personal description of user Ul, the account server 108 may establish this MEK-encrypted copy of that personal-account metadata by grouping the metadata together and using the account-specific MEK as a basis to encrypt that group of metadata.

[0122] In addition, the account-level information that gets provisioned into the second discoverer device 104 could include a double-encrypted copy of the account-specific MEK, namely, of the MEK that is useable as a basis to decrypt the MEK-encrypted copy of the account-specific metadata of the personal account of user Ul. This MEK could be the same MEK used to encrypt the account-specific metadata of the personal account of user Ul. By analogy here, the account server 108 could double-encrypt this MEK by imposing (i) a layer of encryption specific to the personal account of user Ul and (ii) a second layer of encryption specific to the advertiser device 100. For instance, the account server 108 could first encrypt this MEK based on an account-specific seedA that is specific to the personal account of user Ul (e.g., using that account-specific seedA as a basis to dynamically generate an encryption key and using that generated encryption key as a basis to encrypt the MEK), so as to establish a single-encrypted MEK. Then the account server 108 could encrypt that single-encrypted MEK using the DEK specific to the advertiser 100, so as to establish the double-encrypted MEK specific to the personal account of user Ul.

[0123] Further, the account-level information that gets provisioned into the second discoverer device 104 could include the seedA that is specific to the personal account of user Ul. Given this seedA specific to the personal account of user Ul, and given the DEK specific to the advertiser 100, the second discoverer 104 may thereby uncover the MEK specific to the personal account of user Ul. For instance, the second discoverer 104 may use the advertiserspecific DEK as a basis to engage in a first decryption of the double-encrypted MEK specific to the personal account of user Ul, so as to uncover a once-encrypted instance of the accountspecific MEK. Then the second discoverer 104 may use this seedA in the same manner as the account server 108, to correspondingly generate the same encryption key that the account server used as a basis to encrypt the MEK specific to the personal account of user Ul, and the second discoverer 104 may use that generated encryption key as a basis to decrypt the once- encrypted account-specific MEK, so as to thereby uncover the MEK specific to the personal account of user U 1.

[0124] Given this device-level information associated with advertiser 100 and the related account-level information associated with the personal account of user Ul, the second discoverer 104 could thereby treat the advertisement message 106 from the advertiser 100 as being an advertisement message under the personal account of user Ul, while the first discover 102 treats the very same advertisement message 106 from the advertiser 100 as being an advertisement message under the work account of user U 1. Further, here too, this arrangementmay help to support improved privacy, as each discoverer may gain no information about the user’s other account as to which it does not have a trust relationship.

[0125] For instance, once the second discoverer 104 detects this advertisement message 106 (e.g., through scanning on a predefined wireless channel), the second discoverer 104 may search through one or more instances of seedo pre-provisioned in the second discoverer 104 and may likewise identify the pre-provisioned seedo that works as a basis to decrypt the encrypted DEK carried by the advertisement message 106. The second discoverer 104 may likewise thereby uncover the DEK associated with the advertiser 100. However, rather than mapping the identified seedo to the work-account related information of user U1 as the first discoverer 102 does, the second discoverer 104 may map the identified seedo to the preprovisioned personal-account related information of user Ul. For instance, the second discoverer 104 may map the identified seedo to (i) the MEK-encrypted copy of the accountspecific metadata of the personal account of user Ul, (ii) the double-encrypted MEK specific to the personal account of user Ul, and (iii) the seedA specific to the personal account of user Ul.

[0126] As discussed above, the second discoverer 104 may then likewise doubledecrypt the double-encrypted MEK, first using the DEK specific to the advertiser 100 and then using the seedA specific to the personal account of user Ul, thereby uncovering the MEK specific to the personal account of the user Ul. Then the second discoverer 104 may use this MEK specific to the personal account of user Ul as a basis to decrypt the encrypted accountspecific metadata of the personal account of user Ul.

[0127] Through this process, the second discoverer 104 may thereby uncover the account-specific metadata of the personal account of user Ul, and the second discoverer 104 may make use of that uncovered personal-account metadata to make its nearby-presence detection specific to the personal account of user Ul.

[0128] For instance, the second discoverer 104 may present this uncovered personal-account metadata to user U3 in connection with a prompt requesting user U3 to approve establishment of a data session between the advertiser 100 and the second discoverer 103. Upon receipt of approval from user U3 in response to this prompt, the second discoverer 104 may then send an advertisement response message to the advertiser 100, and the advertiser 100 and second discoverer 104 may work to establish a data session with each other through which they may then exchange useful information with each other.

[0129] Accordingly, with this further example process, even though the advertisement message 106 broadcast by the advertiser 100 may have carried just devicespecific information and possibly no account-specific information, the advertisement message 106 (i) can come across at the first discoverer 102 as being an advertisement message from the advertiser 100 specifically under the work account of user U1 and (ii) can come across at the second discoverer 104 as being an advertisement message from the advertiser 100 specifically under the personal account of user U 1.

[0130] Conveniently, the advertiser 100 may thereby achieve multi-account advertisement without a need to separately send an advertisement message respectively under each account. This may thereby help conserve communication resources, processing resources, and power resources at the advertiser. Furthermore, as noted above, this process may optimally scale non-linearly to any number of accounts. For instance, if an advertiser operates under five separate accounts and each account has a trust relationship with a respective discoverer, the advertiser may be able to use the present process to efficiently broadcast a device-specific advertisement message and have each discoverer securely uncover and present the user account metadata applicable to its respective trust relationship, which may thereby facilitate accountspecific nearby-presence processing among other benefits.4. Example Process

[0131] Figure 3 is a flow chart illustrating a method that can be carried out in accordance with the present disclosure for account-specific discovery by a discoverer device that is pre-provisioned with a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device, the pre-provisioned set of data including (i) a first encryption seed, (ii) a second encryption seed, (iii) a double-encrypted MEK, and (iv) encrypted metadata regarding the account configured on the advertiser device.

[0132] As shown in Figure 3, at block 300, the method could involve the discoverer device detecting, based on scanning of a communication channel, a broadcast advertisement message that carries an encrypted DEK associated with the advertiser device. Further, at block 302, the method could involve the discoverer device using the first encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device. Still further, at block 304, the method could involve the discoverer device mapping the first encryption seed to (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata. Yet further, at block 306, the method could involve, based on the mapping, (a) the discoverer using the uncoveredDEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (b) the discoverer device using the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

[0133] In line with the discussion above, the account could be one of multiple accounts configured on the advertiser device, and the DEK could be associated with an identity of the advertiser device, e.g., specific to the advertiser device generally, not specific to a given account of the multiple accounts.

[0134] Further, as discussed above, the discoverer device could store a correlation between the first encryption seed and (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata. That way, once the discoverer device determines that the first encryption seed works to decrypt the encrypted DEK carried by the advertisement message, the discoverer device could refer to the stored correlation as a basis to map the first encryption seed, and thus the uncovered DEK, to the second encryption seed, the doubleencrypted MEK, and the encrypted metadata.

[0135] Still further, as discussed above, the double-encrypted MEK could be established by (i) first encrypting the MEK based on the second encryption seed, thereby producing a single-encrypted MEK and (ii) next encrypting the single-encrypted MEK in a manner that is decryptable by the DEK, thereby producing the double-encrypted MEK. Thus, the act of using the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK could involve (i) first decrypting the double-encrypted MEK based on the DEK, thereby producing the singleencrypted MEK, and (ii) next decrypting the single-encrypted MEK based on the second encryption seed, thereby uncovering the MEK.

[0136] In addition, the DEK could be a symmetric encryption key, in which case encrypting the single-encrypted MEK in a manner that is decryptable by the DEK could involve encrypting the single-encrypted MEK based on the DEK.

[0137] As further discussed above, the encrypted DEK carried by the advertisement message could be established by encrypting the DEK based on the first encryption seed.

[0138] Still further, as discussed above, the act of using the first encryption seed as a basis to decrypt the encrypted DEK could involve using the first encryption seed as a basis to establish a decryption key and using the established decryption key as a basis to decrypt the encrypted DEK.

[0139] In addition, as discussed above, the discoverer device could be preprovisioned with the set of data by a centralized server, such as an account server, based on the trust relationship between the discoverer device and the account configured on the advertiser device. Further, as discussed above, the trust relationship between the discoverer device and the account configured on the advertiser device could be or include a trust relationship between (i) an account configured on the discoverer device and (ii) the account configured on the advertiser device.

[0140] Yet further, as discussed above, the advertisement message could be broadcast by the advertiser device. Therefore, the act of detecting the broadcast advertisement message could involve detecting the advertisement message broadcast by the advertiser device. 5. Example Device

[0141] Figure 4 is a simplified block diagram of a device that could operate as an advertiser or discoverer in line with the present disclosure. As shown in Figure 4, the example device includes a wireless communication interface 400, a processor 402, and non-transitory data storage 404, all of which may be communicatively linked together by a system bus or other connection mechanism 406 and / or may be integrated with each other wholly or partly.

[0142] The wireless communication interface 400 of the example device may include a radio 408 and an associated antenna structure 410. The radio 408 and antenna structure 410 may cooperatively facilitate short-range wireless communication in accordance with Bluetooth or another applicable wireless communication technology, allowing the device to engage in nearby-presence message communication and associated communication.

[0143] The processor 402 may comprise one or more general purpose processors (e.g., microprocessors) and / or one or more special purpose processors (e.g., digital signal processors, application specific integrated circuits, etc.) Further, the non-transitory data storage 404 may comprise one or more volatile and / or non-volatile, removable and / or permanently situated storage components (such as magnetic, optical, flash, RAM, ROM, EPROM, EEPROM, etc.) and may be integrated in whole or in part with the processor 402. Further, as shown, the data storage 404 may embody, encode, hold, or otherwise store program instructions 412 and reference data 414. The program instructions could be executable by the processor 402 to carry out various device operations described herein. The reference data 414 may include various data as described herein, such as the data provisioned as described above for instance.

[0144] Further, the present disclosure contemplates at least one non-transitory computer-readable medium (e.g., one or more volatile and / or non-volatile storage components,such as magnetic, optical, flash, RAM, ROM, EPROM, EEPROM, etc.) having stored thereon program instructions executable by at least one processor to carry out or cause to be carried out various disclosed operations. For instance, the instructions may be executable by at least one processor of a discoverer device to cause the discoverer device to carry out operations described herein for account-specific discovery.

[0145] Example embodiments have been described above. Those skilled in the art will understand, however, that changes and modifications may be made to these embodiments without departing from the true scope and spirit of the invention.

Claims

CLAIMSWhat is claimed is:

1. A method for discovery by a discoverer device, wherein the discoverer device is pre-provisioned with a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device, the pre-provisioned set of data including an encryption seed and encrypted metadata regarding the account configured on the advertiser device, the method comprising: detecting, by the discoverer device, based on scanning of a communication channel, a broadcast advertisement message that carries an encrypted device-encryption-key (DEK) associated with the advertiser device; using, by the discoverer device, the encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device; and using, by the discoverer device, at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

2. The method of claim 1, wherein the account is one of multiple accounts configured on the advertiser device, and wherein the DEK is associated with an identity of the advertiser device and is not specific to a given account of the multiple accounts.

3. The method of claim 1, wherein the encrypted DEK carried by the advertisement message is established by encrypting the DEK based on the encryption seed.

4. The method of claim 1, wherein using the encryption seed as a basis to decrypt the encrypted DEK comprises using the encryption seed as a basis to establish a decryption key and using the established decryption key to decrypt the encrypted DEK.

5. The method of claim 1, wherein the discoverer device is pre-provisioned with the set of data by a centralized server based on the trust relationship between the discoverer device and the account configured on the advertiser device.

6. The method of claim 1, wherein the trust relationship between the discoverer device and the account configured on the advertiser device comprises a trust relationship between (i) an account configured on the discoverer device and (ii) the account configured on the advertiser device.

7. The method of claim 1, wherein the advertisement message is broadcast by the advertiser device.

8. The method of claim 1, wherein the encryption seed is a first encryption seed, wherein the pre-provisioned set of data further includes a second encryption seed and a doubleencrypted metadata-encryption key (MEK), the method further comprising: mapping, by the discoverer device, the first encryption seed to (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata, wherein using, by the discoverer device, at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device comprises (a) using, by the discoverer device, the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the doubleencrypted MEK and thereby to uncover the MEK and (b) using, by the discoverer device, the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

9. The method of claim 8, wherein the discoverer device stores a correlation between the first encryption seed and (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata, and wherein mapping of the first encryption seed to the second encryption seed, the doubleencrypted MEK, and the encrypted metadata comprises referring to the stored correlation as a basis to map the first encryption seed to the second encryption seed, the double-encrypted MEK, and the encrypted metadata.

10. The method of claim 8,wherein the double-encrypted MEK is established by (i) first encrypting the MEK based on the second encryption seed, thereby producing a single-encrypted MEK and (ii) next encrypting the single-encrypted MEK in a manner that is decryptable by the DEK, thereby producing the double-encrypted MEK, and wherein using the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK comprises (i) first decrypting the double-encrypted MEK based on the DEK, thereby producing the singleencrypted MEK, and (ii) next decrypting the single-encrypted MEK based on the second encryption seed, thereby uncovering the MEK.

11. The method of claim 10, wherein the DEK is a symmetric encryption key, and wherein encrypting the single-encrypted MEK in a manner that is decryptable by the DEK comprises encrypting the single-encrypted MEK based on the DEK.

12. A di scoverer device compri sing : a wireless communication interface; a processor; and non-transitory data storage, wherein the non-transitory data storage has stored thereon a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device, the set of data including an encryption seed and encrypted metadata regarding the account configured on the advertiser device, wherein the non-transitory data storage further has stored thereon program instructions executable by the processor to cause the discoverer device to carry out operations for discovery, the operations including: detecting based on scanning of a communication channel, a broadcast advertisement message that carries an encrypted device-encryption-key (DEK) associated with the advertiser device, using the encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device, andusing at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

13. The discoverer device of claim 12, wherein the account is one of multiple accounts configured on the advertiser device, and wherein the DEK is associated with an identity of the advertiser device and is not specific to a given account of the multiple accounts.

14. The discoverer device of claim 12, wherein the encrypted DEK carried by the advertisement message is established by encrypting the DEK based on the first encryption seed.

15. The discoverer device of claim 12, wherein using the first encryption seed as a basis to decrypt the encrypted DEK comprises using the first encryption seed as a basis to establish a decryption key and using the established decryption key to decrypt the encrypted DEK.

16. The discoverer device of claim 12, wherein the discoverer device is preprovisioned with the set of data by a centralized server based on the trust relationship between the discoverer device and the account configured on the advertiser device.

17. The discoverer device of claim 12, wherein the trust relationship between the discoverer device and the account configured on the advertiser device comprises a trust relationship between (i) an account configured on the discoverer device and (ii) the account configured on the advertiser device.

18. The discoverer device of claim 12, wherein the advertisement message is broadcast by the advertiser device.

19. The discoverer device of claim 12, wherein the encryption seed is a first encryption seed, wherein the set of data further includes a second encryption seed and a doubleencrypted metadata-encryption key (MEK), and wherein the operations further include: mapping the first encryption seed to (i) the second encryption seed, (ii) the doubleencrypted MEK, and (iii) the encrypted metadata,wherein using at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device comprises (a) using the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (b) using the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

20. The discoverer device of claim 19, wherein the discoverer device stores a correlation between the first encryption seed and (i) the second encryption seed, (ii) the double-encrypted MEK, and (iii) the encrypted metadata, and wherein mapping of the first encryption seed to the second encryption seed, the doubleencrypted MEK, and the encrypted metadata comprises referring to the stored correlation as a basis to map the first encryption seed to the second encryption seed, the double-encrypted MEK, and the encrypted metadata.

21. The discoverer device of claim 19, wherein the double-encrypted MEK is established by (i) first encrypting the MEK based on the second encryption seed, thereby producing a single-encrypted MEK and (ii) next encrypting the single-encrypted MEK in a manner that is decryptable by the DEK, thereby producing the double-encrypted MEK, and wherein using the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK comprises (i) first decrypting the double-encrypted MEK based on the DEK, thereby producing the singleencrypted MEK, and (ii) next decrypting the single-encrypted MEK based on the second encryption seed, thereby uncovering the MEK.

22. At least one non-transitory computer-readable medium having stored thereon program instructions executable by at least one processor of a discoverer device to cause the discoverer device to carry out operations for discovery, wherein the discoverer device is pre-provisioned with a set of data based on a trust relationship between the discoverer device and an account configured on an advertiser device,the set of data including an encryption seed and encrypted metadata regarding the account configured on the advertiser device, and wherein the operations comprise: detecting based on scanning of a communication channel, a broadcast advertisement message that carries an encrypted device-encryption-key (DEK) associated with the advertiser device, using the encryption seed as a basis to decrypt the encrypted DEK from the detected advertisement message and thereby to uncover the DEK associated with the advertiser device, and using at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

23. The at least one non-transitory computer-readable medium of claim 22, wherein the encryption seed is a first encryption seed, wherein the set of data further includes a second encryption seed and a double-encrypted metadata-encryption key (MEK), and wherein the operations further comprise: mapping the first encryption seed to (i) the second encryption seed, (ii) the doubleencrypted MEK, and (iii) the encrypted metadata, wherein using at least the uncovered DEK as a basis to facilitate decrypting the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device comprises (a) using the uncovered DEK and the second encryption seed cooperatively as a basis to decrypt the double-encrypted MEK and thereby to uncover the MEK and (b) using the uncovered MEK as a basis to decrypt the encrypted metadata and thereby to uncover the metadata regarding the account configured on the advertiser device.

24. A computer program comprising program instructions executable by a processor of the discoverer device to perform a method according to any of claims 1-11.

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