Hierarchical Key Structure

The Kunpeng intrinsic commercial cryptographic module employs a three-layer key management structure, including the root key, master key/user key, and session key.

Figure 1 Three-layer key system

The hierarchical key structure is as follows.

**Table 1** Hierarchical key structure
Key Type	Key Function
Root key (symmetric key)	Burnt into the CPU eFuse during the chip manufacturing stage, implementing a per-device unique key mechanism. Derives the master key and user keys for encryption and protection.
User key (asymmetric key)	Protects session keys. Derived from the root key and stored after being encrypted.
Master key (symmetric key)	Protects session keys. Derived from the root key and stored after being encrypted.
Session key (symmetric key)	Used in actual services. Encrypted and exported using user keys, the device key, or the master key after being generated.

Parent topic: Functions and Features