Custody Models
QuantumSafe supports different custody models for PQC key management. Currently, only BYOK is available. Managed and Threshold custody are on the roadmap.Overview
| Model | Version | Status | Private Key Location | User Control |
|---|---|---|---|---|
| BYOK | v1.0 | Available | Client device | Full |
| Managed | v1.5 | Available | AWS KMS HSM | Shared |
| Threshold | v2.0 | Planned | Split across parties (MPC) | Distributed |
BYOK (Bring Your Own Key) — v1.0
The current and default custody model.How It Works
The SDK generates PQC key pairs locally on your device. Only the public key is registered with QuantumSafe. The private key never leaves your environment.
Your Responsibility
You are fully responsible for private key storage, backup, and security. If lost, the key cannot be recovered.
Advantages
- Full control over private keys
- No trust required in QuantumSafe infrastructure
- Lowest attack surface
- Works offline (key generation only)
Disadvantages
- No recovery mechanism if private key is lost
- Requires secure key storage infrastructure
- Single point of failure (the device holding the key)
Recommended Storage
| Environment | Storage |
|---|---|
| Development | Encrypted file on disk |
| Production | HSM, AWS KMS, Azure Key Vault, GCP Cloud KMS |
| Mobile | Secure Enclave (iOS) / StrongBox (Android) |
| Hardware | Dedicated HSM appliance |
Managed Custody — v1.5 (Available)
KMS Managed mode stores your PQC private keys in AWS KMS hardware security modules (FIPS 140-3 Level 3). Keys are non-exportable — they never leave the HSM.KMS Managed Keys require Pro plan ($499/mo) or above. See the KMS Managed guide for a full walkthrough.
- Key generation happens in the KMS (keys never exist in plaintext outside the HSM)
- Signing happens in the KMS via the KMS Sign endpoint
- Access control via IAM policies and QuantumSafe permissions
BYOK vs Managed Comparison
| Feature | BYOK (v1) | Managed (v1.5) |
|---|---|---|
| Key Location | Your device | AWS KMS HSM |
| Security Level | Software | FIPS 140-3 Level 3 |
| Private Key Access | You control | Non-exportable |
| Cost | Free | 0.15/10K ops |
| Plan Required | Free+ | Pro+ |
| Algorithms | All | ML-DSA only |
Algorithm Compatibility
| Algorithm | BYOK | Managed (KMS) |
|---|---|---|
| ML-DSA-44 | ✓ | ✓ |
| ML-DSA-65 | ✓ | ✓ |
| ML-DSA-87 | ✓ | ✓ |
| SLH-DSA | ✓ | ✗ |
| FN-DSA | ✓ | ✗ |
Advantages
- No private key management burden
- FIPS 140-3 Level 3 hardware security
- Automatic backup and disaster recovery
- HSM-grade security
- Audit logging
Disadvantages
- Trust in QuantumSafe + AWS KMS
- Requires network connectivity for signing
- Higher latency for signing operations
- Monthly KMS costs (0.15/10K signing ops)
Migration from BYOK
Migration from BYOK to Managed:- Export your ML-DSA private key from local storage
- Import into KMS via QuantumSafe’s secure import flow
- Verify the import succeeded
- Delete the local copy
Cost Breakdown
- $1 per key per month
- $0.15 per 10,000 signing operations
- Verification is free (uses public key locally)
Threshold Custody — v2.0 (Planned)
Threshold custody is planned for v2.0 and is not yet available. The details below are subject to change.
How It Works
- Key is split into
nshares with a threshold oft - Any
tofnparties can collaborate to sign - No party ever sees the full private key
- Signing is performed via an MPC protocol
Advantages
- No single point of failure
- Compromise of
t-1parties does not reveal the key - Suitable for organizational custody
- Can implement approval workflows
Disadvantages
- Higher complexity
- Requires coordination between parties
- Higher latency for signing
- MPC protocol overhead
Choosing a Model
- Individual Developer
- Startup / Small Team
- Enterprise
Use BYOK. You maintain full control and can store keys in your existing infrastructure.