How is the private key securely stored within Auth0?

Hi, I’m onboarding a customer to use SSO with SAML, but their conformance / compliance team have questions about the use of our private key (i.e. the one Auth0 uses for signing our requests). I’ve tried searching the site but have come up blank.
The question is: Is the private key encrypted with a Strong Cipher (AES / 3DES) and/or Strong Passphrase (min 12 characters with upper case, lowercase, numbers and symbols)?
I think this is referring how the private key is stored in our tenant.
Is there any information on this?