# US 2014/0153714 A1 · Challenge-Response Authentication Using a Masked Response Value > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153714 A1 - Document ID: US20140153714A1 - Status: Published application - Kind: A1 - Application number: 13/691,101 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Certicom Corp. - Applicants: Certicom Corp. - Inventors: Robert John Lambert - Web page: https://patentgrep.com/patent/US20140153714A1 ## CPC - H04L 9/3271: {using challenge-response} - H04L 9/3236: {using cryptographic hash functions} - H04W 12/06: Authentication - H04L 2209/04: Masking or blinding - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Challenge-response authentication protocols are disclosed herein, including systems and methods for a first device to authenticate a second device. In one embodiment, the following operations are performed by the first device: (a) sending to the second device: (i) a challenge value corresponding to an expected response value known by the first device, and (ii) a hiding value; (b) receiving from the second device a masked response value; (c) obtaining an expected masked response value from the expected response value and the hiding value; and (d) determining whether the expected masked response value matches the masked response value received from the second device. The operations from the perspective of the second device are also disclosed, which in some embodiments include computing the masked response value using the challenge value, the hiding value, and secret information known to the second device. ## Claims ### Claim 1 A method for a second device to be authenticated by a first device, the method performed by the second device and comprising: the second device receiving from the first device a challenge value and a hiding value; the second device computing a masked response value using the challenge value, the hiding value, and secret information known to the second device; the second device sending to the first device the masked response value for comparison to an expected masked response value. ### Claim 2 (depends on 1) The method of claim 1 further comprising repeating the method using a different hiding value received from the first device. ### Claim 3 (depends on 1) The method of claim 1, wherein said computing the masked response value comprises first computing a response value using the challenge value and the secret information, and then computing the masked response value using the response value and the hiding value. ### Claim 4 (depends on 1) The method of claim 1, wherein said computing the masked response value comprises first computing a cryptographic hash of a message comprising the challenge value and the secret information to obtain a response value, and then computing a cryptographic hash of another message comprising the response value and the hiding value to obtain the masked response value. ### Claim 5 (depends on 4) The method of claim 4, wherein the cryptographic hash used to obtain the response value is the same as the cryptographic hash used to obtain the masked response value. ### Claim 6 (depends on 1) The method of claim 1, wherein said computing the masked response value comprises computing a cryptographic hash of a message comprising the challenge value, the hiding value, and the secret information. ### Claim 7 (depends on 6) The method of claim 6, wherein the cryptographic hash is one that is progressively computed and is the same as a cryptographic hash used by the first device to compute the expected masked response value. ### Claim 8 (depends on 1) The method of claim 1, wherein the expected masked response value is to be computed by the first device using the hiding value and an expected response value known by the first device and corresponding to the challenge value. ### Claim 9 (depends on 1) The method of claim 1, wherein the secret information is not known to the first device. ### Claim 10 (depends on 1) The method of claim 1, wherein the first device is a mobile device and the second device is a battery. ### Claim 11 A device comprising: a memory configured to store secret information; an interface configured to receive from another device a challenge value and a hiding value, and to send to the another device a masked response value for comparison to an expected masked response value; and a processor configured to compute the masked response value using the challenge value, the hiding value, and the secret information. ### Claim 12 (depends on 11) The device of claim 11, wherein the interface is further configured to receive from the another device different hiding values such that a subsequent hiding value received from the another device and used in computing a subsequent masked response value is different from the hiding value. ### Claim 13 (depends on 11) The device of claim 11, wherein the processor is configured to compute the masked response value by first computing a response value using the challenge value and the secret information, and then computing the masked response value using the response value and the hiding value. ### Claim 14 (depends on 11) The device of claim 11, wherein the processor is configured to compute the masked response value by first computing a cryptographic hash of a message comprising the challenge value and the secret information to obtain a response value, and then computing a cryptographic hash of another message comprising the response value and the hiding value to obtain the masked response value. ### Claim 15 (depends on 11) The device of claim 11, wherein the processor is configured to compute the masked response value by computing a cryptographic hash of a message comprising the challenge value, the hiding value, and the secret information. ### Claim 16 (depends on 11) The device of claim 11, wherein the expected masked response value is to be computed by the another device using the hiding value and an expected response value known by the another device and corresponding to the challenge value. ### Claim 17 (depends on 11) The device of claim 11, wherein the device is a battery and the another device is a mobile device. ### Claim 18 A processor readable medium having stored thereon processor readable instructions for a second device to be authenticated by a first device; the processor readable instructions, when executed, cause the second device to perform operations comprising: receiving from the first device a challenge value and a hiding value; computing a masked response value using the challenge value, the hiding value, and secret information known to the second device; sending to the first device the masked response value for comparison to an expected masked response value. ### Claim 19 (depends on 18) The processor readable medium of claim 18, wherein the instructions, when executed, further cause the second device to repeat the operations using a different hiding value received from the first device. ### Claim 20 (depends on 18) The processor readable medium of claim 18, wherein said computing the masked response value comprises either: first computing a cryptographic hash of a message comprising the challenge value and the secret information to obtain a response value, and then computing a cryptographic hash of another message comprising the response value and the hiding value to obtain the masked response value; or computing a cryptographic hash of a message comprising the challenge value, the hiding value, and the secret information.