Seed Vault (BIP39)

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Generate BIP39 seed phrases directly in your browser using the Web Crypto API.

Seed (BIP39) is a human-readable backup phrase for your wallet private keys. You use it to recover your wallet on a new device or after loss/reset.

Crypto Seed Best Practices

  • Use a clean computer – a live USB with Tails OS (or simpler: Ubuntu booted from USB) or a machine that has never been online. Not required but recommended.
  • Access this website in Private/Incognito mode – no extensions installed.
  • Run completely offline – unplug the network cable, turn off WiFi before generating a new seed phrase.
  • Write by hand on paper first (then optionally stamp onto metal). Split the seed phrase using the 3-of-5 model generated by this tool: each card hides different words with XXXX. Any 3 cards combined reveal the full seed phrase. Store the 5 physical cards in different locations so it’s hard to find 3 pieces together (e.g., bank safe deposit box, home safe, office safe, with a trusted heir, etc.). Never store your seed in any digital form (screenshot, phone photo, notes, cloud storage, even clipboard copy).
  • Clear state after writing your seed – close the Private/Incognito browser and restart your machine.
  • When entering your seed into a hot wallet on your phone, make sure your keyboard is from a trusted source, not a third-party keyboard that may log your keystrokes.
  • Practice wallet recovery on an offline/dummy device before storing large funds.
  • On your phone, always keep hot wallets inside the manufacturer’s built-in Private Space / Private Zone (e.g., Secure Folder on Samsung, Parallel Space on Honor). The phone should have both software and hardware security such as Samsung Knox. Warning: do not use third-party Private Space / Private Zone apps.

How It Works

Entropy is generated with your browser CSPRNG (Web Crypto API).
BIP39 checksum is computed from SHA-256 before converting to 11-bit word indexes.
Validation checks both word presence and checksum correctness.