What matters now.
Post-quantum migration is now an engineering programme. The serious first step is inventory: TLS, VPN, SSH, code signing, machine identity, wallets, firmware, backups, PKI and archival encryption.
The highest-priority exposure is long-lived confidentiality: information harvested now that must remain protected into the quantum era. Systems with slow replacement cycles require early planning.
Crypto-agility is the practical target. Organisations need the ability to change algorithms, certificates, key lifecycles and supplier dependencies without re-architecting everything under emergency pressure.