Intel removes all traces of the Root Seal Key after it is burned into the processor's fuses during manufacturing.
Unable to validate how the Root Seal Key (RSK) is kept private from Intel, which manufactures the processors.
During the processor manufacturing process, the RSKs are randomly generated and burned into e-fuses in the processor. After the key is burned into the processor, Intel removes all traces of the key from its systems.
Refer to the Root Keys section of EPID Provisioning and Attestation Services - Intel for more information.