This seed creation method allows you to generate a cryptographically secure seed phrase by entering 11 words (for 12-word seed) or 23 words (for 24-word seed) manually, then calculating the final word with proper checksum validation. The final word (12th or 24th) incorporates additional entropy and ensures the seed phrase meets BIP39 standards.
Complete Process with All Screenshots
- Navigate: Main Menu → Tools → “Calc 12th/24th word”
- Choose Length: Select 12 words or 24 words
- Enter Existing Words: Use the on-screen keyboard with intelligent word suggestions:
- Key A: Move up in the suggestions list
- Key C: Move down in the suggestions list
- Key B: Select the highlighted suggested word
Entropy Methods for Final Word Calculation
The system provides three different entropy sources to calculate the final word, ensuring cryptographic security:
🪙 Coin Flip Entropy Method
- Flip a physical coin exactly 7 times
- For each flip, select 1 for Heads or 0 for Tails by pressing the Joystick
- This method provides 7 bits of entropy for the final word calculation
- The system displays your binary string and calculates the checksum
📝 Word Selection Entropy Method
- Choose any word from the BIP39 wordlist as your entropy source
- The selected word provides the entropy bits needed for final word calculation
🔢 Finalize with Zeros Method
- Uses a simple 7-bit string of zeros plus the calculated 4-bit checksum
- This is the simplest method but still produces a valid final word
Final Word Display and Completion
Final Word Display
- Shows the calculated final word with full derivation details
- Displays the entropy source used and checksum calculation
Completion Screen
- Review the complete seed phrase with the calculated final word
- Your seed is now ready for backup and use
📚 Technical Note: The final word in any BIP39 seed contains both entropy bits and checksum bits. The checksum ensures the seed phrase is mathematically valid and helps detect transcription errors.