GM (Generate Mnemonic)

Demo: gm.zlog.in | Source: github.com/zlog-in/gm

Deterministic BIP39 mnemonic generator. Turn memorable input into a standard mnemonic phrase — reproducible forever, stored nowhere.

Use your life to define randomness. Your seed comes from three dimensions you choose:

• A meaningful text — a personal story, a private quote, a passage only you know.
• A meaningful file — a photo, a video, a voice recording, a GIF, any format.
• A meaningful number — via custom iteration count. A date, a phone number, a number only you know.

Combine any or all. Each dimension an attacker must guess multiplies the search space exponentially. You don't memorize anything random — your memories ARE the key.

How It Works

Your input (text / file / both) + iteration count
        │
        ▼
   PBKDF2-SHA256  (custom iterations, no salt)
        │
        ▼
   BIP39 mnemonic  (12 or 24 words)

Same input, same iterations, same output — on any device, any browser, any time.

Usage

git clone https://github.com/zlog-in/gm.git
cd gm
open index.html        # macOS
# or: xdg-open index.html   (Linux)
# or: start index.html      (Windows)
# or: just double-click index.html in your file manager

No install, no build, no dependencies, no network. Works offline — disconnect your WiFi if you want.

Steps

1. Enter text and/or upload a file.
2. Choose word count (12 / 24), language (EN / 中文 / 日本語), and iteration count.
3. Click Generate Mnemonic.
4. Copy the result or inspect the raw hex.

Features

• Zero dependencies — single 42KB HTML file, everything embedded.
• Offline-only — no network requests, ever. Verify in DevTools Network tab.
• Three BIP39 wordlists — English, Chinese Simplified, Japanese (from bitcoin/bips).
• Configurable iterations — 100K / 500K / 1M (default) / 5M / custom.
• Wordlist reference panel — browse all 2048 words, with generated words highlighted.
• Self-verifying — runs 6 cryptographic tests on every page load (check browser console).

Security Model

Layer	Protection
Input unpredictability	Your personal text/files are the entropy source
Computational cost	1M PBKDF2 iterations = ~seconds per brute-force guess
Offline execution	No data leaves your browser
Standard algorithms	PBKDF2, SHA-256, BIP39 — audited, NIST-approved
Native crypto	Web Crypto API (BoringSSL / NSS), not hand-written JS

The mnemonic is only as strong as your input. "password123" produces a valid-looking 12-word phrase with near-zero real security. Choose input that only you can reproduce.

Self-Verification

Open browser console (F12) after loading. You should see:

[GM] All 6 cryptographic tests passed
   PASS  BIP39 vector 1
   PASS  BIP39 vector 2
   PASS  BIP39 vector 3
   PASS  BIP39 vector 4
   PASS  PBKDF2 (hello, 1M iter, 128bit)
   PASS  PBKDF2 (hello, 1M iter, 256bit)

Tests 1-4 use official BIP39 test vectors. Tests 5-6 cross-reference against Python hashlib.pbkdf2_hmac.

Important Notes

• Byte-exact: "Hello" and "hello" produce different results. A trailing space matters. A re-compressed photo is a different file.
• Order matters: text + file ≠ file + text. Text is always concatenated first.
• Iterations are part of the protocol: generating with 1M and restoring with 500K gives a different mnemonic.
• Iterations as implicit salt: GM has no traditional salt, but a custom iteration count serves the same purpose — different iterations on the same input produce completely different outputs. Pick a number that means something to you (a date, a phone number, any integer from 1 to 100,000,000) and it becomes your "second key". An attacker must guess both your input and your iteration count.
• Language only changes words, not entropy: switching from English to Chinese produces different words but the same underlying hex.

Files

gm/
├── index.html      The tool (HTML + CSS + JS + wordlists)
├── TECHNICAL.md    Technical specification
├── BLOG.md         Technical blog post (Chinese)
└── README.md       This file

Browser Support

Chrome 37+ / Firefox 34+ / Safari 11+ / Edge 37+ (any browser with Web Crypto API).

Disclaimer

This tool is experimental and provided as-is for research and educational purposes only. It has not been independently audited. Do not use it to secure assets you cannot afford to lose. The authors assume no responsibility for any loss resulting from the use of this tool.

License

MIT