# Harvest now, decrypt later

Harvest now, decrypt later is an attack in which adversaries record encrypted traffic or steal encrypted archives today, expecting to decrypt them once quantum computers can break the encryption. Any data that must stay confidential for years, including key backups, is already exposed to it.

## Countering an attack that has already started

The defense is to make today's ciphertext quantum-resistant: hybrid post-quantum key exchange on every long-lived connection, quantum-safe encryption on backups and archives, and inventories identifying where classical encryption still protects long-lived secrets.

Taurus deployed hybrid X25519 plus ML-KEM key exchange across SSH, TLS 1.3, and VPN connectivity, and quantum-safe backup encryption, specifically to eliminate harvest-now-decrypt-later exposure from external parties.

FAQ:

- Which data is most exposed? Anything confidential for a decade or more: key backups, client records, and recorded transport sessions. Data already exfiltrated cannot be re-protected, which is why transport and backups migrate first.

Related: https://www.taurushq.com/security/post-quantum-ready/ https://www.taurushq.com/glossary/key-backup-and-recovery/ https://www.taurushq.com/glossary/ml-kem/

Learn more: https://www.taurushq.com/glossary/harvest-now-decrypt-later/