# US 11,115,199 B2 · Information processing method, and computer program product > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,199 B2 - Document ID: US11115199B2 - Status: Granted - Kind: B2 - Application number: 16/508,928 - Filed: 2019-07-11 - Published: 2020-01-23 - Granted: 2021-09-07 - Earliest claimed: 2018-07-18 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kabushiki Kaisha Toshiba - Inventors: Akira Murakami - Web page: https://patentgrep.com/patent/US11115199B2 ## CPC - H04L 9/0852: {Quantum cryptography (transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03)} - H04L 9/0858: {Details about key distillation or coding, e.g. reconciliation, error correction, privacy amplification, polarisation coding or phase coding} - H04B 10/70: Photonic quantum communication - H04L 9/0855: {involving additional nodes, e.g. quantum relays, repeaters, intermediate nodes or remote nodes} - H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying} - H04L 9/0894: {Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract According to one embodiment, an information processing method includes a monitoring step and a key provision step. The monitoring step includes monitoring an operation state of an information processing device including a key generating unit that generates key information shared among a plurality of devices using a quantum key distribution technique. The key provision step includes providing the generated key information when the operation state satisfies a predetermined condition and stopping the provision of the generated key information when the operation state does not satisfy the condition. ## Claims ### Claim 1 An information processing method, comprising: monitoring an operation state of an information processing device including a key generating unit that generates key information shared among a plurality of devices using a quantum key distribution technique; providing the generated key information when the operation state satisfies a predetermined condition; stopping provision of the generated key information when the operation state does not satisfy the condition; and outputting output information by at least one of display on a display device, output by light, output by a sound, and output to an output destination via a network when the provision of the key information is stopped, the output information indicating that the provision of the key information is stopped. ### Claim 2 (depends on 1) The information processing method according to claim 1, wherein the operation state indicates a state of an operation that is not taken into account in a key length calculation of a privacy amplification. ### Claim 3 (depends on 1) The information processing method according to claim 1, further comprising: storing the generated key information in a storage; and deleting the key information from the storage when the operation state does not satisfy the condition. ### Claim 4 (depends on 1) The information processing method according to claim 1, further comprising, collecting the operation state in real time or each time a predetermined period elapses, and determining whether or not the operation state satisfies the condition on the basis of the collected operation state. ### Claim 5 (depends on 1) The information processing method according to claim 1, wherein the operation state includes at least one of a randomness of a random number used for generating the key information, an authentication setting of communication, a characteristic of a light source of a photon to be transmitted, and a characteristic of a modulating unit that modulates the photon. ### Claim 6 (depends on 1) The information processing method according to claim 1, wherein the operation state includes an output result of a detection device for detecting unauthorized access to the information processing device. ### Claim 7 (depends on 1) The information processing method according to claim 1, wherein the outputting includes outputting the output information when unauthorized access to the information processing device is detected. ### Claim 8 (depends on 7) The information processing method according to claim 7, wherein the unauthorized access is detected by at least one of a detection device that detects opening of a housing of the information processing device and a detection device that detects intrusion of an object into a region in which the information processing device is installed. ### Claim 9 (depends on 1) The information processing method according to claim 1, wherein the outputting includes outputting, together with the output information, information indicating a cause by which the provision of the key information is stopped. ### Claim 10 (depends on 1) The information processing method according to claim 1, wherein the condition is a condition obtained by a theory that proves safety of the key information provided by the quantum key distribution technique. ### Claim 11 An information processing method, comprising: receiving second determination information for determining an operation state of a key generation process by a key generating unit that generates key information shared among a plurality of devices using a quantum key distribution technique; stopping provision of the generated key information when the second determination information indicating the occurrence of an abnormality is received; and outputting output information by at least one of display on a display device, output by light, output by a sound, and output to an output destination via a network when the provision of the key information is stopped, the output information indicating that the provision of the key information is stopped. ### Claim 12 A computer program product having a non-transitory computer readable medium including programmed instructions, wherein the instructions, when executed by a computer, cause the computer to perform: monitoring an operation state of an information processing device including a key generating unit that generates key information shared among a plurality of devices using a quantum key distribution technique; providing the generated key information when the operation state satisfies a predetermined condition; stopping provision of the generated key information when the operation state does not satisfy the condition; and outputting output information by at least one of display on a display device, output by light, output by a sound, and output to an output destination via a network when the provision of the key information is stopped, the output information indicating that the provision of the key information is stopped.