Multi-node expandable cryptographic processing system

A primary hardware security module (HSM) used in a system for securely managing a plurality of HSMs, the primary HSM comprising:

• a memory;
• and
• an electronic processor configured to
• in response to receiving a request from a host device to enter a security association mode, enter the security association mode,
• in response to receiving a request from the host device to generate a multi-HSM exchange key while in the security association mode, generate the multi-HSM exchange key,
• using a temporary key generated using a key agreement protocol, encrypt the multi-HSM exchange key, and share an encrypted multi-HSM exchange key with a subordinate HSM via the host device,
• receive a traffic encryption key (TEK),
• encrypt the TEK with the multi-HSM exchange key, and
• export an encrypted TEK to the host device.

A host device used in a system for securely managing a plurality of hardware security modules (HSMs), the host device comprising:

• a memory;
• and
• an electronic processor configured to
• designate a first HSM as a primary HSM,
• designate a second HSM as a subordinate HSM,
• activate a security association mode in the first HSM,
• receive an encrypted multi-HSM exchange key,
• provide the encrypted multi-HSM exchange key to the subordinate HSM,
• deactivate the security association mode in the first HSM,
• receive an encrypted traffic encryption key (TEK) from the first HSM, the encrypted TEK being encrypted with the multi-HSM exchange key,
• store the encrypted TEK in the memory, and
• provide the encrypted TEK to the second HSM.

A method for securely managing a plurality of hardware security modules (HSMs) each including a memory and an electronic processor, the method comprising:

• designating, with a host device, a first HSM as a primary HSM;
• designating, with the host device, a second HSM as a subordinate HSM;
• activating, with the host device, a security association mode;
• in response to the security association mode being activated, generating, with the first HSM, a multi-HSM exchange key;
• generating a temporary key using a key agreement protocol between the first HSM and the second HSM;
• encrypting, with the first HSM, the multi-HSM exchange key using the temporary key;
• sharing, with the first HSM, the encrypted multi-HSM exchange key with the second HSM via the host device;
• in response to sharing, with the first HSM, the encrypted multi-HSM exchange key with the second HSM, deactivating the security association mode;
• receiving, with the first HSM, a traffic encryption key (TEK);
• in response to receiving the TEK, notifying, with the first HSM, the host device of having received the TEK;
• transmitting, with the host device, a request to the first HSM to encrypt the TEK using the multi-HSM exchange key;
• receiving, with the host device, an encrypted TEK from the first HSM;
• storing, with the host device, the encrypted TEK in a host memory;
• providing, with the host device, the encrypted TEK to the second HSM;
• and
• invalidating or erasing, with the second HSM, the TEK upon completion of a processing session.