A method is provided for generating a key ladder for securely communicating between a first device and a second device using a first device symmetric key and a chip-unique private key. The method includes generating a second processor-specific first device symmetric key from a first processor-specific first device symmetric key and a first identifier (CPU_ID), generating a chip-unique first device application private key (CUAPrK) from a second identifier and the second processor-specific first device symmetric key, generating a chip-unique first device application public key (CUAPuK) from the chip-unique first device application private key (CUAPrK), and transmitting the chip-unique first device application public key (CUAPuK) and an identifier of the processor to the second device.