US 11,888,970 B2
Method and system for deriving key from basekey built-in chip
Zhaohui Du, Shanghai (CN)
Assigned to MONTAGE ELECTRONICS (SHANGHAI) CO., LTD., Shanghai (CN)
Filed by MONTAGE ELECTRONICS (SHANGHAI) CO., LTD., China (Shanghai) Pilot Free Trade Zone (CN)
Filed on Oct. 19, 2021, as Appl. No. 17/505,023.
Claims priority of application No. 202011295488.7 (CN), filed on Nov. 18, 2020.
Prior Publication US 2022/0158828 A1, May 19, 2022
Int. Cl. H04L 9/08 (2006.01); G06F 17/16 (2006.01); H04L 9/32 (2006.01); G06F 8/71 (2018.01)
CPC H04L 9/0825 (2013.01) [G06F 17/16 (2013.01); H04L 9/0866 (2013.01); H04L 9/3239 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for deriving a key from a basekey built-in a chip, comprising:
performing, by a hardware processor, steps of:
obtaining a basekey built-in the chip and a current version number when the chip starts up and runs read-only boot code;
constructing a oriented tree, each node in the oriented tree corresponds to a version, a topological order number of each node indicates a version number corresponding to the node, the basekey is located at a root node of the oriented tree, a version number of any node is smaller than a version number of its parent node,
wherein the oriented tree adopts at least two different one-way functions; and
performing iterations on the basekey by visiting the oriented tree in a topological order to obtain a derived key of a current version,
wherein the step of performing iterations on the basekey by visiting the oriented tree in the topological order to obtain the derived key of the current version further comprises:
hiding nodes with version numbers larger than the current version number in the oriented tree; and
performing iterations on the basekey to generate derived keys of version numbers corresponding to all nodes whose parent nodes are hidden.