Workshop Description
Cloud-stored data faces a specific quantum threat that differs from data in transit. Data at rest with long retention requirements is the primary target for harvest-now-decrypt-later attacks: an adversary who captures encrypted backups, database dumps, or object storage snapshots today can decrypt them once a cryptographically relevant quantum computer exists. The Mosca inequality makes this concrete: if the data must remain confidential for 15 years and migration will take 3 years, any data encrypted today with classical key agreement is already at risk if a quantum computer arrives within 18 years.
This workshop examines the encryption architecture of each cloud storage layer: object storage (S3 SSE-KMS, Azure Blob CMEK, GCS CMEK), database TDE (RDS, Cloud SQL, Azure SQL), and backup/archival encryption including tape and cold storage with regulatory retention holds of 7 to 25 years. The core vulnerability is not AES-256 itself (which remains quantum-resistant for symmetric encryption) but the key wrapping and key agreement operations that use RSA or ECDH to protect the key hierarchy. Participants build a cryptographic inventory of their stored data, score each data class using the Mosca inequality, and develop a migration roadmap that sequences re-encryption by risk priority. The session covers practical re-encryption strategies at petabyte scale, including background re-encryption with versioned objects, migration checkpointing, and cloud provider PQC roadmap alignment.
What participants cover
- HNDL threat model for stored data: why long-retention encrypted data is the highest-priority quantum migration target and how the Mosca inequality quantifies exposure
- Cloud storage encryption audit: object storage encryption modes (SSE-S3, SSE-KMS, SSE-C, Azure Blob, GCS CMEK), database TDE key hierarchies, and backup encryption dependencies
- Data classification and risk scoring: mapping sensitivity levels against retention periods to produce a quantum risk score per data class
- Key hierarchy vulnerability: identifying which key wrapping and key agreement operations use RSA or ECDH (quantum-vulnerable) versus AES (quantum-resistant)
- Re-encryption at scale: strategies for migrating petabytes of stored data to PQC-protected key hierarchies without service disruption
- Compliance drivers: NIST FIPS 203 (ML-KEM) for key encapsulation, CNSA 2.0 deadlines, and sector-specific retention rules (GDPR, financial services, healthcare)