What Is a Stateless Air-Gapped Signer?

Traditional hardware wallets (such as Ledger, Trezor, or Coldcard) are stateful devices. They store your private keys permanently on internal flash memory or Secure Element microchips. Every time you turn on the device, your private keys reside inside the hardware silicon awaiting PIN entry.

A Stateless Air-Gapped Signer (such as SeedSigner, Specter DIY, or Blockstream Jade in stateless mode) takes a radically different approach:

  1. Zero Persistent Storage: The hardware contains no flash memory storing private keys. When powered off, the device is completely empty silicon.
  2. Ephemeral Memory Execution: You load your seed phrase during a signing session via an animated QR code scan or manual dice roll entry into RAM.
  3. Instant Memory Wipe: The moment you unplug the power cable, volatile RAM loses power and all seed material vanishes instantly.
  4. Air-Gapped Optical Communication: The device communicates with your computer strictly using a built-in camera and screen via QR codes—no USB cables, Bluetooth, or Wi-Fi chips.

Security Breakdown: Stateless Signers vs. Stateful Hardware

Stateless signers offer major architectural advantages against supply chain and firmware exploits:

  • Immunity to On-Device Extraction: Physical extraction attacks (like side-channel analysis or voltage glitching) cannot extract keys from a powered-off stateless signer because the keys do not exist on the device.
  • Hardware Supply Chain Neutralization: You can build a SeedSigner using off-the-shelf Raspberry Pi Zero hardware and camera modules purchased from standard electronics distributors.
  • Verifiable Open-Source Firmware: Operating code is loaded from a micro-SD card running verifiably reproducible open-source software.

However, stateless signers require you to present your seed phrase (via SeedQR, physical metal plates, or manual input) every time you sign a transaction.

Integrating Stateless Signers with ZeroLatch Private Mode

Because stateless signers rely on external SeedQR cards or metal backups, maintaining a secure, automated recovery runbook for your family or estate is paramount.

By using ZeroLatch Private Mode, you can store encrypted digital backups of your stateless SeedQR descriptors, wallet maps, and signing instructions without compromising your zero-knowledge boundary:

  • Client-Side Browser Encryption: Encrypt your SeedQR export files and recovery instructions using AES-256-GCM before uploading.
  • Strong Argon2id Derivation: Your Private Mode vault is protected by a 24-word ZeroLatch phrase using Argon2id and HKDF-SHA-512.
  • Absolute Zero-Knowledge Privacy: ZeroLatch never receives or holds your Private decryption secret.
  • Automated Dead Man's Switch: If you miss scheduled check-ins, your encrypted stateless runbook is released to your designated beneficiary.

Protect Your Stateless Seed Runbook with Private Mode →