SeedWitness

A diagnostic tool for checking device-derived seed words and addresses.

SeedWitness makes entropy-to-seed calculations reproducible. Supply test dice rolls or coin flips, then compare the resulting BIP39 seed words and addresses with another device or implementation using the same procedure and settings. The entropy comes from outside the device; SeedWitness adds no randomness of its own.

For test data only, not live wallet secrets. SeedWitness is not a wallet or transaction signer, and is not intended for checking a live wallet backup. Use test material expected to control no real-world value.

What you can test

• Entropy to words. Reproduce the documented SHA-256-to-BIP39 calculation from dice rolls or coin flips.
• Address derivation. Derive addresses from a test mnemonic and compare them with another implementation using matching derivation settings.
• Watch-only derivation. Save a test account's public key and examine its addresses without entering the test mnemonic again.
• SeedQR and passphrase derivation. Compare test mnemonic exports and dice-derived test passphrases.
• Demonstration mode. Explore the test flows with clearly marked demonstration data.

What a matching result means

Agreement checks the calculation on the inputs tested. It does not prove a device is secure, certify its randomness, or establish that dice were fair or privately rolled. SeedSigner and SeedWitness share the embit address-derivation library, so matching addresses between them are not an independent check of that library.

Hardware and build verification

A resistive touchscreen board in a clear acrylic case, running MicroPython with MIT-licensed application code. Published tools let you compare the installed build with reference firmware and a file manifest. This is not a secure hardware wallet: USB is a full debug interface, the board has Wi-Fi and Bluetooth hardware, and it has no secure boot, flash encryption or secure element. The application does not use networking.

Five standard dice included. Spare dice sets are sold separately.

Read the project documentation and security limitations for the exact comparison procedure and supported test workflows.