Patent ID: 11888970
Assignee: MONTAGE ELECTRONICS (SHANGHAI) CO
Field: Digital communication (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 6:
7. A system for deriving a key from a basekey built-in a chip, comprising:
an acquisition module, configured to obtain a basekey built-in a chip and a current version number when the chip starts up and runs read-only boot code;
a construction module, configured to construct an 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;
a calculation module, configured to:
perform iterations on the basekey by visiting the oriented tree in a topological order to obtain a derived key of a current version;
hide nodes with version numbers larger than the current version number in the oriented tree; and
perform iterations on the basekey to generate derived keys of version numbers corresponding to all nodes whose parent nodes are hidden; and

a hardware processor that executes the acquisition module, the construction module, and the calculation module.