Bitcoin BIP39 Seed Generator (Dice Method)

A secure, offline web tool for generating Bitcoin BIP39 seed phrases using physical dice rolls as an entropy source. This tool allows you to create cryptographically secure seed phrases for Bitcoin and other cryptocurrency wallets while maintaining full transparency of the generation process.

Features

• Generate 12, 18, or 24-word BIP39 seed phrases
• Uses physical dice rolls as entropy source
• Full transparency of the entropy-to-seed conversion process
• Detailed checksum calculation display
• Real-time binary conversion visualization
• Comprehensive BIP39 compliance verification
• Offline capable - can be downloaded and run locally

Security Features

• All calculations performed client-side
• No external dependencies or API calls
• Can be used on an air-gapped computer
• Source code is fully readable and verifiable
• Complete transparency of the seed generation process
• Implements BIP39 specification exactly

How It Works

1. Entropy Generation

   • 12 words: 128 bits (121 from dice + 7 checksum)
   • 18 words: 192 bits (186 from dice + 6 checksum)
   • 24 words: 256 bits (253 from dice + 3 checksum)

2. Dice to Binary Conversion

   • Each die roll provides 1 bit of entropy
   • Rolls 1-3 → binary 0
   • Rolls 4-6 → binary 1

3. Checksum Process

   • SHA256 hash of entropy bits
   • First N bits used as checksum (where N = entropy_length ÷ 32)
   • Checksum appended to entropy bits

4. Word Generation

   • Combined bits split into 11-bit segments
   • Each 11-bit segment maps to a word from BIP39 word list
   • Final word includes checksum bits

Why Use Dice?

Physical dice provide true random entropy, unlike computer-generated random numbers which are technically pseudo-random. Benefits include:

1. True Randomness: Physical dice provide genuine randomness from the real world
2. No Digital Trace: The entropy source never touches a computer's memory
3. Visual Verification: You can see and verify each source of entropy
4. Immune to Software Bugs: No reliance on computer random number generators
5. Offline Security: Complete air-gap capability

Entropy Requirements

Seed Length	Total Bits	Entropy Bits	Checksum Bits	Dice Rolls Needed
12 words	128 bits	121 bits	7 bits	121 rolls
18 words	192 bits	186 bits	6 bits	186 rolls
24 words	256 bits	253 bits	3 bits	253 rolls

Usage

1. Select desired seed length (12, 18, or 24 words)
2. Roll physical dice and enter values (1-6) in each box
3. Values auto-advance as you type
4. Click "Generate" when all rolls are entered
5. Verify the generated seed phrase
6. Save your seed phrase securely

Security Recommendations

1. Use on an air-gapped computer
2. Clear browser cache after use
3. Use a clean/secure environment
4. Never share your seed phrase
5. Make secure backups of generated seeds
6. Verify the seed works before using it with real funds

Technical Details

• Implements BIP39 specification
• Uses SHA256 for checksum generation
• Includes full BIP39 word list
• Performs comprehensive seed verification
• Shows detailed entropy and checksum calculations

Important Links

• BIP39 Specification
• Official BIP39 Word List
• BIP39 Test Vectors
• Bitcoin Improvement Proposals (BIPs)

Verification Process

The tool verifies:

1. Correct seed length (12/18/24 words)
2. All words present in BIP39 word list
3. Valid checksum matching entropy
4. Proper entropy-to-binary conversion
5. Correct word mapping from binary

Local Installation

1. Clone the repository:

   git clone https://github.com/yourusername/bitcoin-bip39-dice-generator.git

2. Open index.html in a web browser

   • No server required
   • No build process needed
   • Works completely offline

Files

• index.html - Main application file
• bip39.js - BIP39 wordlist and SHA256 implementation
• README.md - This documentation

License

MIT License - See LICENSE file for details

Disclaimer

This tool is provided as-is. Always verify generated seeds with a small test amount before using them with significant funds. The authors are not responsible for any lost funds.