How to Protect Systems That Can’t Be Upgraded to PQC

Quick answer. To protect systems that can’t be upgraded to post-quantum cryptography (PQC), give each a dated decision: replace it, tunnel its traffic through a PQC-capable gateway, segment it, minimize its data, or accept risk until a fixed date. Canada’s Cyber Centre says it “may be necessary to isolate such systems on the network or to tunnel traffic” (June 2025).