4.2.1 ECDH
Command
The ECDH
command is used to generate a shared secret between two devices. By
passing an ECC public key from another device and combining it
with the ECC private key stored in a slot or with an ephemeral
key stored in TempKey and doing the reverse on the other device,
both devices will generate the same shared pre-master secret.
This can, then, be further combined with other common data in
both sides to generate a shared session key between the devices.
The KDF
command is often used with TLS sessions
to further diversify the shared secret.