Secure key delivery

At least one processor, comprising:

• one or more logical units to:
• derive, in a software agent executing on a secure processor in a computing device, an initial set of ephemeral keys using a shared secret and a generated nonce;
• transmit a first message containing the generated nonce to a secure key unwrap engine implemented in hardware of the computing device and having a local copy of the shared secret;
• derive, in the secure key unwrap engine, the initial set of ephemeral keys using the shared secret and the generated nonce;
• use a current ephemeral wrapping key, of the initial set of ephemeral keys, to encrypt data to be transmitted while the initial set of ephemeral keys is valid;
• derive, in the software agent and in response to a request to perform a key rotation, a new set of ephemeral keys using a newly-generated nonce and an initial ephemeral derivation key of the initial set of ephemeral keys;
• and
• transmit a second message containing the newly-generated nonce to the secure key unwrap engine, wherein the secure key unwrap engine is able to derive the new set of ephemeral keys using the newly-generated nonce and a locally-stored instance of the initial ephemeral derivation key.

A computer-implemented method, comprising:

• deriving, in a software agent executing on a secure processor in a computing device, an initial set of ephemeral keys using a shared secret and a generated nonce;
• transmitting a first message containing the generated nonce to a secure key unwrap engine implemented in hardware of the computing device and having a local copy of the shared secret;
• deriving, in the secure key unwrap engine, the initial set of ephemeral keys using the shared secret and the generated nonce;
• using a current ephemeral wrapping key, of the initial set of ephemeral keys, to encrypt data to be transmitted while the initial set of ephemeral keys is valid;
• deriving, in the software agent and in response to a request to perform a key rotation, a new set of ephemeral keys using a newly-generated nonce and an initial ephemeral derivation key of the initial set of ephemeral keys;
• and
• transmitting a second message containing the newly-generated nonce to the secure key unwrap engine, wherein the secure key unwrap engine is able to derive the new set of ephemeral keys using the newly-generated nonce and a locally-stored instance of the initial ephemeral derivation key.