# US 10,320,562 B2 · Application specific low-power secure key > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,320,562 B2 - Document ID: US10320562B2 - Status: Granted - Kind: B2 - Application number: 15/169,831 - Filed: 2016-06-01 - Published: 2017-12-07 - Granted: 2019-06-11 - Earliest claimed: 2016-06-01 - Assignees: NXP USA, Inc. - Applicants: Freescale Semiconductor, Inc. - Inventors: Eran Glickman; Ron M. Bar; Omer Sharon - Web page: https://patentgrep.com/patent/US10320562B2 ## CPC - H04L 9/0861: {Generation of secret information including derivation or calculation of cryptographic keys or passwords} - G06F 21/75: by inhibiting the analysis of circuitry or operation - H04L 9/0891: {Revocation or update of secret information, e.g. encryption key update or rekeying} - 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 A key generator including a low-power key adjust circuit, and a high-power key adjust circuit. The low-power key adjust circuit including a storage location to store an original key, a shifter to shift the original key by a number of steps to shift to create a first key, and an output to provide the first key. The high-power key adjust circuit including an input coupled to the output of the low-power key adjust circuit to receive the first key, a scrambler to scramble the first key to create a scrambled key, and select circuitry to select either the first key or the scrambled key to output from the high-power key adjust circuit based on a bit in a configuration register. ## Claims ### Claim 1 A method comprising: shifting, by a shifter of a low-power key adjust circuit, an original key by a number of steps to shift to create a shifted key; providing, from the low-power key adjust circuit, a first key based on the shifted key to a first scrambler of a high-power key adjust circuit; scrambling, at the first scrambler of the high-power key adjust circuit, the first key to create a second key that is scrambled; outputting, at the high-power key adjust circuity, either the first key or the second key from the high-power key adjust circuit based on a select field in a configuration register, wherein if the select field is asserted, the second key is selected, and wherein if the select field is negated, the first key is selected; and encrypting data using either the first key or the second key that is outputted at the high-power key adjust circuitry. ### Claim 2 (depends on 1) The method of claim 1 further comprising: storing, at a storage location of the high-power key adjust circuit, the second key prior to the outputting of the first key or the second key. ### Claim 3 (depends on 1) The method of claim 1 further comprising: scrambling, at a second scrambler of the low-power key adjust circuit, the original key prior to creating the shifted key. ### Claim 4 (depends on 1) The method of claim 1 further comprising: determining, by the low-power key adjust circuit, whether a keep field in the configuration register is set to a predetermined value; and in response to the keep field being set to the predetermined value, storing the shifted key at the low-power key adjust circuit as a new original key, otherwise, shifting the shifted key to revert back to the original key. ### Claim 5 (depends on 1) The method of claim 1 further comprising: determining whether the second key is valid prior to selecting either the first key or the second key; and in response to the second key being valid, storing a first value in a trivial field of the configuration register, otherwise, storing a second value in the trivial field of the configuration register. ### Claim 6 (depends on 1) The method of claim 1 wherein the shifted key is scrambled based on an application identification, wherein the application identification identifies an application to utilize a key output from the high-power key adjust circuit. ### Claim 7 (depends on 1) The method of claim 1 wherein the low-power key adjust circuit is provided power via a battery. ### Claim 8 A key generator comprising: a low-power key adjust circuit comprising a storage location to store an original key, a shifter to shift the original key by a number of steps to shift to create a first key, and an output to provide the first key; and a high-power key adjust circuit comprising an input coupled to the output of the low-power key adjust circuit to receive the first key, a first scrambler to scramble the first key to create a scrambled key, and select circuitry to select either the first key or the scrambled key to output from the high-power key adjust circuit based on a bit in a configuration register; and to encrypt data using either the first key or the scrambled key that is outputted at the high-power key adjust circuitry. ### Claim 9 (depends on 8) The key generator of claim 8 the low-power key adjust circuit further includes: a second scrambler, the second scrambler to scramble the original key prior to the shifter creating the first key. ### Claim 10 (depends on 8) The key generator of claim 8 the low-power key adjust circuit further to determine whether a keep field in the configuration register is set to a predetermined value; and in response to the keep field being set to the predetermined value, to store the first key as a new original key, otherwise, to shift the first key to revert back to the original key. ### Claim 11 (depends on 8) The key generator of claim 8 the high-power key adjust circuit further to determine whether the scrambled key is valid prior to selecting either the first key or the scrambled key; and in response to a carbon copy key being usable, to store a first value in a trivial field of the configuration register, otherwise, to store a second value in the trivial field of the configuration register. ### Claim 12 (depends on 8) The key generator of claim 8 wherein the number of steps to shift the original key is stored as a value in a field of the configuration register. ### Claim 13 (depends on 8) The key generator of claim 8 wherein the first key is scrambled based on an application identification, wherein the application identification identifies an application to utilize a key output from the high-power key adjust circuit. ### Claim 14 (depends on 8) The key generator of claim 8 wherein the low-power key adjust circuit is provided power via a battery. ### Claim 15 A method comprising: shifting, by a shifter of a low-power key adjust circuit, an original key by a number of steps to shift to create a shifted key; providing, from the low-power key adjust circuit, a first key based on the shifted key to a first scrambler of a high-power key adjust circuit; scrambling, at the first scrambler of the high-power key adjust circuit, the first key to create a second key that is scrambled; determining whether the second key is valid; and outputting the second key from the high-power key adjust circuit in response to the second key being valid, otherwise outputting the first key from the high-power key adjust circuit; and encrypting data using either the first key or the second key that s outputted at the high-power key adjust circuitry. ### Claim 16 (depends on 15) The method of claim 15 further comprising: scrambling, at a second scrambler of the low-power key adjust circuit, the original key prior to creating the shifted key. ### Claim 17 (depends on 15) The method of claim 15 further comprising: determining, by the low-power key adjust circuit, whether a keep field in a configuration register is set to a predetermined value; and in response to the keep field being set to the predetermined value, storing the shifted key as a new original key, otherwise, shifting the shifted key to revert back to the original key. ### Claim 18 (depends on 15) The method of claim 15 further comprising: providing, by the low-power key adjust circuit, a ready signal to the high-power key adjust circuit, wherein the ready signal indicates that key shifting is complete and that the first key is valid. ### Claim 19 (depends on 15) The method of claim 15 wherein the number of steps to shift the original key is stored as a value in a field of a configuration register. ### Claim 20 (depends on 15) The method of claim 15 wherein the shifted key is scrambled based on an application identification, wherein the application identification identifies an application to utilize a key output from the high-power key adjust circuit.