Computer-implemented system and method for determining or verifying location

Patent metadata

Field	Value
Publication number	US-12309291-B2
Application number	US-202017427374-A
Country	US
Kind code	B2
Filing date	Jan 20, 2020
Priority date	Feb 1, 2019
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A computer implemented method is provided, which comprises the steps of: broadcasting a request for location data; receiving from a plurality of nodes location data comprising a distance and a public key corresponding to an area proximal to that node; selecting a public key which is common to a set of the plurality of nodes; and requesting the set of nodes to participate in threshold secret sharing to obtain a cryptographic signature associated with the common public key. The method makes use of a blockchain for communicating and verifying data, and includes transferring control of a transaction using the cryptographic signature obtained.

First claim

The invention claimed is:

1. A computer implemented method, comprising the steps of:
broadcasting, by a broadcaster, a signal containing a request for location data;
receiving, from each of a plurality of nodes receiving said signal and determining that the broadcaster is within a predetermined distance of said node, respective location data comprising a plurality of public keys corresponding to respective areas adjacent that node, wherein the location data further comprises a distance attribute;
ranking the public keys based on the distance attributes;
selecting, based on said location data, a common public key which is common to a set of the plurality of nodes, wherein the step of selecting the common public key which is common to the set of the plurality of nodes is performed based on an outcome of the ranking, and wherein the distance attributes comprise a distance from respective nodes to an origin of the request and the ranking comprises ranking the public keys in order of said distances; and
requesting the set of the plurality of nodes to participate in threshold secret sharing to obtain a cryptographic signature associated with the common public key, wherein each of said plurality of nodes has a respective plurality of private key shares, corresponding to said plurality of public keys, and said cryptographic signature is obtained from a threshold number of said private key shares.

2. The method of claim 1 , wherein at least one of:
the step of broadcasting the request for location data comprises broadcasting an identifier for identifying the broadcaster; and
the step of receiving location data further comprises receiving, from each of the plurality of nodes, a public key associated with a respective at least one node.

3. The method of claim 1 , wherein:
the step of requesting the set of the plurality of nodes to participate in threshold secret sharing to obtain a cryptographic signature associated with the common public key comprises providing data to be signed, and wherein:
the data to be signed comprises at least one of: (i) a message; (ii) a hash of the message; and (iii) an identifier for identifying the broadcaster.

4. The method of claim 1 , further comprising the step of receiving from at least one node a respective node signature associated with a public key of the node, validating the node signature, and determining whether to request a node to participate in threshold secret sharing based on an outcome of said validation, and wherein the node signature is further associated with at least one of: (i) a message; (ii) a hash of the message; (iii) an identifier for identifying the broadcaster; (iv) the location data; and (v) the public key of the node.

5. The method of claim 1 , further comprising at least one of the following steps: (i) sending to at least one node a share portion of a cryptographic secret; (ii) relaying from the at least one node to at least one further node a function value encrypted with a public key of the respective at least one further node; (iii) receiving from the plurality of nodes a respective plurality of parts of an intermediate cryptographic value, combining said parts into the intermediate value, and sending the intermediate value to at least one further node; (iv) receiving from the plurality of nodes a respective plurality of parts of the cryptographic signature and combining said plurality of parts into a component of the cryptographic signature; and (v) redeeming a blockchain transaction by supplying thereto the cryptographic signature.

6. A computer implemented method, comprising the steps of:
receiving, at a node, a signal from a broadcaster containing a request for location data;
determining a distance attribute associated with the request;
sending, from said node as a result of receiving said signal and determining that the broadcaster is within a predetermined distance of said node, the location data comprising the distance attribute and a plurality of public keys corresponding to respective areas adjacent that node;
receiving a request to participate in threshold secret sharing to provide a cryptographic signature associated with a common public key which is common to a set of said nodes and is selected based on said location data, wherein the location data further comprises a distance attribute and wherein the common public key which is common to the set of the plurality of nodes is selected based on an outcome of ranking the public keys based on the distance attributes, and wherein the distance attributes comprise a distance from respective nodes to an origin of the request and the ranking comprises ranking the public keys in order of said distances; and
collaborating, with a plurality of nodes, in threshold secret sharing to obtain the cryptographic signature, wherein said node has a respective plurality of private key shares, corresponding to said plurality of public keys, and said cryptographic signature is obtained from a threshold number of said private key shares of a plurality of said nodes.

7. The method according to claim 6 , further comprising the step of determining a further distance attribute.

8. The method according to claim 6 , wherein at least one of:
the step of determining a distance attribute comprises a time of flight measurement; and
the step of receiving the request for location data comprises receiving an identifier for identifying a broadcaster of the request for location data.

9. The method of claim 6 , wherein the step of receiving the request to participate in threshold secret sharing to obtain a cryptographic signature associated with the common public key comprises receiving data to be signed, and wherein the data to be signed comprises at least one of: (i) a message; (ii) a hash of the message; and (iii) an identifier for identifying a broadcaster.

10. The method of claim 6 , wherein the step of sending location data further comprises sending a node public key.

11. The method of claim 6 , further comprising the step of sending to a broadcaster a node signature associated with at least a node public key, and wherein the node signature is further associated with at least one of: (i) a message; (ii) a hash of the message; (iii) an identifier for identifying the broadcaster; (iv) the location data; and (v) the node public key.

12. The method of claim 6 , further comprising at least one of the following steps: (i) sending to a broadcaster of the request to participate in threshold secret sharing a share portion of a cryptographic secret; (ii) sending to the broadcaster at least one function value calculated from a respective value associated with at least one node; (iii) sending to the broadcaster a part of an intermediate cryptographic value and receiving the intermediate value; (iv) sending to the broadcaster a part of the cryptographic signature; and (v) receiving, from the broadcaster, further location data associated with a plurality of the nodes, performing a trilateration calculation to determine a calculated location of the broadcaster, comparing the calculated location to at least the location data, and determining whether to participate in the threshold secret sharing based on an outcome of said comparing.

13. A computer-implemented system comprising:
a processor; and
memory including executable instructions that, as a result of execution by the processor, cause the system to perform the steps of:
broadcasting, by a broadcaster, a request for location data, wherein the location data further comprises a distance attribute;
receiving from each of a plurality of nodes respective location data comprising at least one public key corresponding to a respective at

Assignees

• Nchain Licensing Ag

Inventors

• Wright Craig Steven
• Joseph Daniel

Classifications

• H04L9/50

  using hash chains, e.g. blockchains or hash trees · CPC title

• H04W12/63

  Location-dependent; Proximity-dependent · CPC title

• H04L9/3236

  using cryptographic hash functions · CPC title

• H04L9/0894

  Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage · CPC title

• H04L9/0825

  using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates · CPC title