# Air-gapped custody: banking-grade cold storage

Taurus-PROTECT provides air-gapped cold storage deployed in production under the
world's strictest regulations. The defining requirement: the device holding the
blockchain signing keys must be isolated. Isolating only approval tokens while the
signing system stays connected is not considered air-gapped by most regulators.
Taurus offers two air gap modes, both in production: a technical air gap and a
physical air gap.

Key facts:

- Technical air gap: cross-domain solution with hardware data diode and deep content
  filtering, real-time operation, TUBITAK-grade
- Physical air gap: zero network connectivity, manual transfer via encrypted
  FIPS-certified USB, eliminates network-based HSM exploitation
- Both modes build on quorum approvals with offline signing tokens
- Hardware: FIPS 140-3 Level 3/4 HSMs; audited key ceremonies per CMTA DACS
- Regulatory benchmarks: Hong Kong (HKMA) requires >=98% of client virtual assets in
  air-gapped cold wallets with HSMs in Hong Kong; Turkiye requires >=95% in cold
  wallets with the entire custody stack deployed domestically
- Sovereign deployment: full domestic deployment of policy engine, transaction
  processing, and application supported

FAQ:

- What is air-gapped cold storage? A custody configuration where the signing device
  has no persistent network connection and no automated, programmatic access to
  signing capabilities.
- What is the difference between technical and physical air gap? Technical: data
  flows one way through a hardware diode with content filtering, in real time.
  Physical: no connectivity at all; transfers happen via encrypted FIPS-certified
  USB.
- Is this deployed in production? Yes, under HKMA and TUBITAK regimes.

Learn more: https://www.taurushq.com/security/air-gapped-custody/