Experimental

Offline cryptographic lab.

Create a 256-bit random value with the browser cryptographic API. This page is a limited experiment, not a complete air-gapped wallet or transaction signer.

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Available here

Create 32 random bytes

Select the button once. The result is produced locally with crypto.getRandomValues and displayed as 64 hexadecimal characters.

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In development

Bitcoin derivation

A self-contained offline build of the Bitcoin derivation engine is not available on this page. The public browser lab loads pinned cryptographic libraries from the network, so saving only this page does not create a verified air-gapped release.

private key → secp256k1 public key → HASH160 → Base58Check → Bitcoin address

Read the offline instructions →

Research

Transaction model

The documented model separates an online watch-only machine from an offline signer. PSBT inspection and signing are not implemented in the current Offline Lab.

ONLINE: create unsigned PSBT ↓ QR code or removable media OFFLINE: inspect → verify → sign ↓ signed data ONLINE: broadcast

Never send a private key, WIF or seed phrase through chat, support, analytics, an issue tracker or any networked form.