gap // bit

HOW WILL YOU USE THIS?

This decides how the app behaves - coins, files and secrets alike. Pick once; it sets up everything after it.

■  AIR-GAPPED

FOR SAVINGS & CRITICAL SECRETS

Coins, files and secrets you cannot afford to lose. This device never touches the internet. Every key is created here and never leaves.

To spend, you'll need a second device with internet, running this same app, with a camera. It does the talking - this one only ever signs. Creating keys, receiving and encrypting files need nothing else.
  • Create wallets and keys
  • Show receive addresses
  • Sign transactions
  • Encrypt files and hold their keys
  • No balance on this device
  • No sending or broadcasting here
Choose - locked for this session →

□  STANDARD

FOR SPENDING & EVERYDAY FILES

Behaves like a normal wallet. Check your balance, receive, send, broadcast and encrypt files - online or off, whenever you want.

Nothing is enforced. You'll be warned before each step that connects, and then it is your call. Your keys can end up on a machine that goes online, and if that machine is ever compromised they can be taken.
  • You decide, every time
  • Balance, send and broadcast here
  • Encrypt files here
  • Use a second device or don't
Choose →

₿  BITCOIN

Native segwit, BIP-84. Sign offline, broadcast from a connected device.

Choose →

Ξ  ETHEREUM & ERC-20

ETH and any ERC-20, on Ethereum, Base, Arbitrum, Optimism and Polygon. BIP-44.

Choose →

▣  FILES & SECRETS

Encrypt any file or text. The encrypted file can live anywhere; its key files go somewhere else.

Choose →

⬚  SCAN

Read a code shown by gapbit on another device. Keys and vaults can be saved here as files; a signed transaction can be broadcast.

Choose →

CREATE NEW WALLET

Mint a seed from measured physical entropy, certified on screen. Then make its key files.

Begin →

OPEN EXISTING WALLET

Restore from key files, import a BIP-39 seed, or watch an xpub.

Open →
← back to chain

Physical sources

enables jitter · clock · pointer instantly; asks for mic + camera
MICROPHONE
- H∞
0 b/s idle
CAMERA
- H∞
0 b/s idle
JITTER
- H∞
0 b/s idle
POINTER
- H∞
0 b/s idle
CLOCK
- H∞
0 b/s idle
Certified entropy · SP800-90B, pre-fold
0.0 bits
select an output size below
Output appears here. Nothing is stored or transmitted.
Already have a wallet? Import seed · Restore encrypted file · Watch-only (xpub)
SP800-90B certificate · per source
estimatormiccamjitterpointer

How the entropy stays honest

  • Min-entropy is measured on raw source bits before the fold, as the minimum of eight SP800-90B estimators - a structured source collapses toward zero and is caught.
  • The gapbit φ fold (φ · e · plastic · Zeckendorf, all public constants) braids the sources and stirs the pool. It conditions only - it adds no entropy, and hides no constant.
  • Release requires ≥ 2× the output size in certified bits; entropy is then spent, never reused.
  • Combined mode XORs the result with the OS generator: provably at least as strong as the standard tool, plus independent physical sources you can watch being measured.
  • Extraction is a Toeplitz/LHL step (ε = 2⁻⁶⁴) with a deterministic public seed; finalization is HKDF-SHA-512. In physical-only mode nothing in the key path touches the OS generator.
pool stirs 0
Hold the other screen steady in frame.
SELF-TESTS HKDF BIP-39 BIP-39 seed extractor seed
file hash: not verified
gapbit.com