Post-quantum cryptography migration lags inside networks as legacy devices stall

Post-quantum cryptographic algorithms are standardised and already in use at internet edges, with browsers and major CDNs enabling hybrid key exchange. The author argues the harder task is inventorying internal systems such as load balancers, VPNs, industrial gateways, and older device firmware that assumed algorithms would never change. Internal migration is moving far slower than the edge, leaving weak links that could be exploited through harvest-now-decrypt-later attacks. Performance costs of the new algorithms are small for computation but significant for larger key and signature sizes, which is why key exchange is expected to roll out before signatures. Firmware and code-signing chains are flagged as likely sources of future incidents, since long-lived root keys and non-updatable devices may remain stuck on algorithms that will eventually be considered broken.