BIP-39 Dice Entropy & Mnemonic Seed Generator.

Generate and verify BIP-39 mnemonic seed phrases client-side with zero network egress. Supports 128/256-bit Web Crypto CSPRNG, physical dice roll entropy, and checksum validation.

Free Runs in your browser Data: Web Crypto API

Trading & Calculation Currency:

Currency:

Words:

Web Crypto CSPRNG

Uses your browser's native cryptographic pseudo-random number generator (crypto.getRandomValues) to generate 128 bits of high-entropy randomness.

Entropy bits:128 bits

Checksum size:4 bits

Security strength:Military-grade (BIP-39)

Air-Gapped Security Rule

Never paste private seed phrases containing real funds into browser tabs. Store large balances on a certified hardware security element.

Secure with Ledger Hardware Wallet

Generated 12-Word SeedChecksum OK

Air-gapped client execution (0 network egress)BIP-0039 Standard

Specification & Methodology

Understanding your results.

A rigorous breakdown of the mathematical equations, market assumptions, and step-by-step calculations powering this tool.

Executive Summary & Cryptographic Standards

The BIP-39 standard bridges 128-bit or 256-bit cryptographic entropy with human readability, converting raw bitstreams into 12 or 24 English words with integrated SHA-256 error-detection checksums. Whether testing physical dice randomness or verifying mnemonic checksum validity, strict client-side isolation protects keys from remote exposure.

Wordlist Size 2,048 Words (11 bits / word)

Checksum Verification SHA-256 First 4 or 8 Bits

Execution Context Air-Gapped Client

Mathematical Specification

BIP-39 Entropy to Word Mapping Mechanics.

Specification 01 Bitstream Slicing

Total Bits = ENT + (ENT / 32) → Words = Total Bits / 11

For 12 words: 128 bits entropy + 4 bits SHA-256 checksum = 132 bits / 11 = 12 indices. For 24 words: 256 bits entropy + 8 bits checksum = 264 bits / 11 = 24 indices.

Specification 02 Key Derivation Pipeline

Seed = PBKDF2(Mnemonic, "mnemonic" + Passphrase, 2048, 512, HMAC-SHA512)

The standard derives a master 512-bit binary seed through 2,048 rounds of HMAC-SHA512 hashing, establishing computational hardness against offline brute-force attacks.

Entropy Generation

Step-by-Step 12-Word Checksum Derivation.

Step 1: Raw Entropy 128 Bits (16 Bytes) CSPRNG or 50 dice rolls

Step 2: SHA-256 Hash First 4 Bits Appended to entropy

Step 3: 11-Bit Chunks 12 Integer Values Each between 0 and 2047

Step 4: Word Lookup 12 English Words Checksum verified

Operational Guide

How to use this tool.

Step-by-step workflow instructions to get the most accurate calculations for your trading strategy.

1
Choose Entropy Generator Mode: Select Hardware CSPRNG (native browser crypto), Physical Dice Entropy (manual dice rolls), or Checksum Validator in the top bar.
2
Select Word Count: Choose between 12 words (128 bits of entropy) or 24 words (256 bits of entropy) based on your target wallet compatibility.
3
Input Physical Dice Rolls (Optional): If in Dice mode, roll a 6-sided die and enter each number (1 - 6) via the keypad to generate purely mechanical, air-gapped randomness.
4
Verify Word Checksums: If in Validator mode, paste your 12 or 24 words to verify whether the final word satisfies the mathematical SHA-256 checksum.
5
Shoulder-Surfing Masking & Backup: Toggle the "Mask" button to hide words when in public, or tap "Copy All" to copy the seed phrase to your clipboard.

Privacy & safety.

Our BIP-39 Seed Generator executes completely offline within your browser with zero network egress. No seed phrases, word indices, or dice inputs are ever sent to any remote server or stored in local storage.