The TPM is a popular security chip that exists in almost every computer and most phones. We rely on each node's TPM to generate Proof of Trust data that can undergo remote attestation by a verifier.
TPM is the main component of the Trusted Computing technology. Here's a good simulator to get some hands on experience with TPM: https://google.github.io/tpm-js/.
For a quick overview of Trusted Computing please go to this Stanford page or for more detail visit the trusted computing group.