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Hardware Security Modules (HSM) - PKCS11

A hardware security module (HSM) is a physical piece of equipment which is designed specifically to protect cryptographic keys and aid with cryptographical processing. HSMs are designed to manage sensitive information and are generally able to be connected and disconnected from a computer trying to use the HSM.

Why an HSM

Without a doubt the biggest benefit of an HSM is that it is a physical piece of hardware. This means that any cryptographic keys protecting data is stored in the HSM and those keys are able to be removed from any given device which had the HSM attached. Because these keys are not kept as files on a computer but are instead stored inside a physical piece of equipment attached to the computer it is more secure since there are no files for an attacker to find and copy. With an HSM you can be sure that they only computer with the relevant key is the one with the HSM attached to it.

Another benefit of HSMs is that they are focused on security. The keys stored inside of many if not all HSMs are designed to not be able to be exported. This means that there's no chance for these keys to be extracted remotely and used outside of the HSM itself, further increasing the security of these important keys.

Enabling a Ziti Endpoint Using an HSM

Enabling a Ziti endpoint to utilize an HSM is straight forward but does require a bit of technical understanding. We have provided a couple of guides on how to enable an HSM with Ziti. The Ziti SDKs all interact with HSMs which support and provide a PKCS#11 library. PKCS#11 is a specification that outlines the programming interface software can use to interact with cryptographic hardware such as smart cards or HSMs.


We have included a couple of quickstarts illustrating two different PKCS#11 drivers to help with understanding.

You will want to go to the OpenSC Project as it is what provides the pkcs11-tool which is used to interact with the HSMs.

The first quickstart is based on softhsm. This one focuses on software that provides an emulated HSM. This is useful for learning and understanding but it is not an actual HSM. Being software it doesn't have the important benefit of being a physical device but it does have one substantial advantage; it's entirely free.

The second quickstart uses an actual physical device - a Yubico Yubikey. The specific key we used is a Yubikey 5 nfc.