# US 12,225,115 B2 · Secure shared key establishment for peer to peer communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,115 B2 - Document ID: US12225115B2 - Status: Granted - Kind: B2 - Application number: 18/149,565 - Filed: 2023-01-03 - Published: 2023-05-18 - Granted: 2025-02-11 - Earliest claimed: 2023-01-03 - Assignees: Visa International Service Association - Applicants: Visa International Service Association - Inventors: Eric Le Saint - Web page: https://patentgrep.com/patent/US12225115B2 ## CPC - H04L 9/085: {Secret sharing or secret splitting, e.g. threshold schemes} - G06F 9/442: {Shutdown} - G06F 21/602: {Providing cryptographic facilities or services} - H04L 9/0825: {using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates} - H04L 9/0861: {Generation of secret information including derivation or calculation of cryptographic keys or passwords} - H04L 9/0863: {involving passwords or one-time passwords (network architectures or network communication protocols for using one-time keys in a packet data network H04L63/067)} - H04L 9/0869: {involving random numbers or seeds} - H04L 9/0897: {involving additional devices, e.g. trusted platform module [TPM], smartcard or USB} - H04L 9/3226: {using a predetermined code, e.g. password, passphrase or PIN (network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083)} - H04L 9/3247: {involving digital signatures} - H04L 9/3263: {involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements (network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823)} - H04L 2209/805: Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor - H04L 2209/84: Vehicles - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Systems and methods for secure peer-to-peer communications are described. Devices registered into trusted network may be capable of establishing a shared data encryption key (DEK). In embodiments, each device may be configured to obtain a share of a data encryption key (DEKi) that can be stored locally. The shares may be shares in an M of N Secret Sharing Scheme. This may involve a network that includes an integer, N, devices, and in which M devices may share a secret (i.e. the DEK) during communications, M being an integer less than or equal to N. To obtain the entire DEK during encryption/decryption, a requesting device may send requests to M of N devices for their shares of the DEK. Once M shares are obtained, they may be used generate the DEK for encrypting/decrypting data between the devices. ## Claims ### Claim 1 A method performed by a computing device, the method comprising: receiving, from a requesting device in a trusted network, a share request for a share of a data encryption key, the trusted network including the requesting device, the computing device, and one or more other computing devices; retrieving a first encrypted local share of the data encryption key from a memory, wherein the first encrypted local share of the data encryption key is encrypted using a local public key of the computing device; decrypting the first encrypted local share using a local private key of the computing device to obtain a local share, wherein the local private key is derived by a key generator using a plurality of derivation components including a network address of the computing device, a random number generated by the computing device, and an encrypted secret of the computing device, and wherein the local public key of the computing device is derived based on the local private key; re-encrypting the local share using a public key of the requesting device to obtain a second encrypted local share; and sending the second encrypted local share to the requesting device, wherein the requesting device (1) generates the data encryption key from (a) the second encrypted local share and one or more encrypted local shares received from the one or more other computing devices and (b) a local encrypted share stored in the requesting device and (2) uses the data encryption key to perform a cryptographic operation. ### Claim 2 (depends on 1) The method of claim 1, wherein the share request comprises a certificate or identifier associated with the certificate for the requesting device, the method further comprising: comparing the certificate for the requesting device to a registry of certificates for N devices in the trusted network; and determining that the requesting device is trusted based on the comparing. ### Claim 3 (depends on 1) The method of claim 1, wherein a total number of devices included in the trusted network is N devices, the computing device generating the data encryption key from M of N shares, wherein N is an integer, and M is an integer less than or equal to N. ### Claim 4 (depends on 1) The method of claim 1, wherein the local private key and the local public key are generated by: generating the random number; obtaining the network address of the computing device; sending the random number and the network address of the computing device to the key generator as derivation components, wherein the key generator derives the local private key from the derivation components and derives the public key from the local private key; receiving the local private key and the local public key from the key generator; and storing the local private key and the local public key in the memory of the computing device. ### Claim 5 (depends on 4) The method of claim 4, wherein decrypting the local share comprises: retrieving the local private key from the memory of the computing device; and decrypting the local share using the local private key. ### Claim 6 (depends on 1) The method of claim 1, further comprising: checking one or more of: a location of the requesting device, an authentication state of the requesting device, and system parameters of the requesting device; and authenticating the requesting device based on the checking. ### Claim 7 (depends on 3) The method of claim 3, wherein the N shares of the data encryption key are shares in a Shamir's Secret Sharing Scheme. ### Claim 8 A system comprising: one or more processors; and a non-transitory computer readable medium storing a plurality of instructions that, when executed, control the one or more processors to perform a method comprising: receiving, from a requesting device in a trusted network, a share request for a share of a data encryption key, the trusted network including the requesting device, a computing device, and one or more other computing devices; retrieving a first encrypted local share of the data encryption key from a memory, wherein the first encrypted local share of the data encryption key is encrypted using a local public key of the computing device; decrypting the first encrypted local share using a local private key of the computing device to obtain a local share, wherein the local private key is derived by a key generator using a plurality of derivation components including a network address of the computing device, a random number generated by the computing device, and an encrypted secret of the computing device, and wherein the local public key of the computing device is derived based on the local private key; re-encrypting the local share using a public key of the requesting device to obtain a second encrypted local share; and sending the second encrypted local share to the requesting device, wherein the requesting device (1) generates the data encryption key from (a) one or more shares including the second encrypted local share and one or more encrypted local shares received from the one or more other computing devices and (b) a local encrypted share stored in the requesting device and (2) uses the data encryption key to perform a cryptographic operation. ### Claim 9 (depends on 8) The system of claim 8, wherein the share request comprises a certificate or identifier associated with the certificate for the requesting device, the method further comprising: comparing the certificate for the requesting device to a registry of certificates for N devices included in the trusted network; and determining that the requesting device is trusted based on the comparing. ### Claim 10 (depends on 8) The system of claim 8, wherein N is an integer, and wherein M is an integer less than or equal to N. ### Claim 11 (depends on 8) The system of claim 8, wherein the local private key and the local public key are generated by: generating the random number; obtaining the network address of the computing device; sending the random number and the network address of the computing device to the key generator as derivation components, wherein the key generator derives the local private key from the derivation components and derives the public key from the local private key; receiving the local private key and the public key from the key generator; and storing the local private key and the local public key in the memory of the computing device. ### Claim 12 (depends on 11) The system of claim 11, wherein decrypting the local share comprises: retrieving the local private key from the memory of the computing device; and decrypting the local share using the local private key. ### Claim 13 (depends on 8) The system of claim 8, wherein the method further comprises: checking one or more of: a location of the requesting device, an authentication state of the requesting device, and system parameters of the requesting device; and authenticating the requesting device based on the checking. ### Claim 14 (depends on 8) The system of claim 8, wherein N shares of the data encryption key are shares in a Shamir's Secret Sharing Scheme. ### Claim 15 A non-transitory computer readable medium storing specific computer-executable instructions that, when executed by a processor, cause: receiving, from a requesting device in a trusted network, a share request for a share of a data encryption key, the trusted network including the requesting device, a computing device, and one or more other computing devices; retrieving a first encrypted local share of the data encryption key from a memory, wherein the first encrypted local share of the data encryption key is encrypted using a local public key of the computing device; decrypting the first encrypted local share using a local private key of the computing device to obtain a local share, wherein the local private key is derived by a key generator using a plurality of derivation components including a network address of the computing device, a random number generated by the computing device, and an encrypted secret of the computing device, and wherein the local public key of the computing device is derived based on the local private key; re-encrypting the local share using a public key of the requesting device to obtain a second encrypted local share; and sending the second encrypted local share to the requesting device, wherein the requesting device (1) generates the data encryption key from (a) one or more shares including the second encrypted local share and one or more encrypted local shares received from the one or more other computing devices and (b) a local encrypted share stored in the requesting device and (2) uses the data encryption key to perform a cryptographic operation. ### Claim 16 (depends on 15) The non-transitory computer readable medium storing specific computer-executable instructions of claim 15, wherein the share request comprises a certificate or identifier associated with the certificate for the requesting device, the processor being further configured for: comparing the certificate for the requesting device to a registry of certificates for N devices included in the trusted network; and determining that the requesting device is trusted based on the comparing. ### Claim 17 (depends on 15) The non-transitory computer readable medium storing specific computer-executable instructions of claim 15, wherein N is an integer, and wherein M is an integer less than or equal to N. ### Claim 18 (depends on 15) The non-transitory computer readable medium storing specific computer-executable instructions of claim 15, wherein the local private key and the local public key are generated by: generating the random number; obtaining the network address of the computing device; sending the random number and the network address of the computing device to the key generator as derivation components, wherein the key generator derives the local private key from the derivation components and derives the public key from the local private key; receiving the local private key and the public key from the key generator; and storing the local private key and the local public key in the memory of the computing device. ### Claim 19 (depends on 15) The non-transitory computer readable medium storing specific computer-executable instructions of claim 15, wherein decrypting the local share comprises: retrieving the local private key from the memory of the computing device; and decrypting the local share using the local private key. ### Claim 20 (depends on 15) The non-transitory computer readable medium storing specific computer-executable instructions of claim 15, wherein N shares of the data encryption key are shares in a Shamir's Secret Sharing Scheme.