interstellar

A command-line tool for managing cryptocurrency mnemonics using BIP39 and SLIP39 standards. This tool allows you to split, combine, and convert mnemonic phrases for secure key management.

✨ Features

• BIP39 Support: Generate, validate, and split BIP39 mnemonic phrases
• SLIP39 Support: Create Shamir Secret Sharing (SLIP39) shares from mnemonics
• Flexible Splitting: Deconstruct 24-word mnemonics into multiple 12-word parts
• Share Reconstruction: Reconstruct mnemonics from SLIP39 shares with threshold requirements
• Digit Mode: Convert mnemonics to/from numeric format for easier backup (1-indexed: BIP39 uses 1-2048, SLIP39 uses 1-1024)

💖 Support

Love this tool? Your support means the world! ❤️

Currency	Address	QR
₿ BTC	bc1qwn7ea6s8wqx66hl5rr2supk4kv7qtcxnlqcqfk
Ξ ETH	0x7cdB1861AC1B4385521a6e16dF198e7bc43fDE5f
ɱ XMR	463fMSWyDrk9DVQ8QCiAir8TQd4h3aRAiDGA8CKKjknGaip7cnHGmS7bQmxSiS2aYtE9tT31Zf7dSbK1wyVARNgA9pkzVxX
◈ BNB	0x7cdB1861AC1B4385521a6e16dF198e7bc43fDE5f

📦 Installation

Homebrew (macOS/Linux)

brew tap alkalescent/tap
brew trust alkalescent/tap
brew install interstellar

PyPI (Recommended)

uv pip install interstellar

After installation, use either the command directly or as a Python module:

# Direct command
interstellar --help

# As Python module (if direct command not in PATH)
uv run python -m interstellar --help

From Source

Clone the repository and install in development mode:

git clone https://github.com/alkalescent/interstellar.git
cd interstellar
make install DEV=1  # Install with dev dependencies

Pre-built Binaries

Download from GitHub Releases:

Note: In the filenames and commands, replace {os} with your operating system (e.g., linux, macos). The examples below use linux. For Windows, you may need to use a tool like 7-Zip to extract .tar.gz archives.

For Portable, download and run directly:

chmod +x interstellar-linux-portable
./interstellar-linux-portable --help

For Fast, extract the archive and run from within:

tar -xzf interstellar-linux-fast.tar.gz
./cli.dist/interstellar --help

Build from Source

Build your own binaries using Nuitka:

git clone https://github.com/alkalescent/interstellar.git
cd interstellar

# Build portable (single file, slower startup)
MODE=onefile make build

# Build fast (directory, faster startup)
MODE=standalone make build

🚀 Usage

The CLI provides two main commands: deconstruct and reconstruct.

Deconstruct Command

Split a BIP39 mnemonic into multiple parts or SLIP39 shares.

From command line:

interstellar deconstruct --mnemonic "your 24 word mnemonic phrase here..."

From file:

interstellar deconstruct --filename seed.txt

Options:

• --mnemonic: BIP39 mnemonic to deconstruct (default: empty, reads from file)
• --filename: File containing the BIP39 mnemonic (default: empty)
• --standard: Output format: BIP39 or SLIP39 (default: SLIP39)
• --required: Required shares for SLIP39 reconstruction (default: 2)
• --total: Total SLIP39 shares to generate (default: 3)
• --digits: Output numeric format instead of words (default: false)

Output Format (JSON):

For BIP39:

[
  {"standard": "BIP39", "mnemonic": "first part words..."},
  {"standard": "BIP39", "mnemonic": "second part words..."}
]

For SLIP39:

{
  "standard": "SLIP39",
  "shares": [
    ["share1 group1", "share2 group1", "share3 group1"],
    ["share1 group2", "share2 group2", "share3 group2"]
  ]
}

Example: Create SLIP39 shares

interstellar deconstruct \
  --mnemonic "word1 word2 ... word24" \
  --standard SLIP39 \
  --required 2 \
  --total 3

Example: Split into BIP39 parts

interstellar deconstruct \
  --mnemonic "word1 word2 ... word24" \
  --standard BIP39

Reconstruct Command

Reconstruct a BIP39 mnemonic from shares or parts.

From command line (semicolon and comma delimited):

interstellar reconstruct --shares "group1_share1,group1_share2;group2_share1,group2_share2"

From file:

interstellar reconstruct --filename shares.txt

Options:

• --shares: Shares to reconstruct, formatted as semicolon-separated groups with comma-separated shares (default: empty, reads from file)
• --filename: File containing shares (default: empty)
• --standard: Input format: BIP39 or SLIP39 (default: SLIP39)
• --digits: Input is in numeric format (default: false)

Output Format (JSON):

{
  "standard": "BIP39",
  "mnemonic": "reconstructed 24 word mnemonic phrase..."
}

Example: Reconstruct from SLIP39 shares (CLI)

interstellar reconstruct \
  --shares "group1_share1,group1_share2;group2_share1,group2_share2" \
  --standard SLIP39

Example: Reconstruct from file

interstellar reconstruct --filename shares.txt --standard SLIP39

📁 Files

Input Files

For deconstruct command: The file should contain the mnemonic phrase:

word1 word2 word3 ... word24

For reconstruct command: Shares should be grouped by line, with comma-separated shares within each group:

group1_share1,group1_share2
group2_share1,group2_share2

For example, with a 2-of-3 SLIP39 scheme split into 2 BIP39 parts:

academic acid ... (20 words),academic always ... (20 words)
academic arcade ... (20 words),academic axes ... (20 words)

Command-Line Format

When using --shares on the command line:

• Use commas (,) to separate shares within a group
• Use semicolons (;) to separate groups
• Example: "group1_share1,group1_share2;group2_share1,group2_share2"

JSON Output

All commands output JSON for easy parsing and piping:

# Extract just the shares
interstellar deconstruct --filename seed.txt | jq -r '.shares'

# Extract the reconstructed mnemonic
interstellar reconstruct --filename shares.txt | jq -r '.mnemonic'

# Save output to file
interstellar deconstruct --mnemonic "word1 ..." > output.json

🧪 Testing

Run the test suite:

uv run python -m pytest -v

Run with coverage reporting (requires 90% coverage):

uv run python -m pytest --cov --cov-report=term-missing --cov-fail-under=90

🔐 Security

⚠️ Important Security Considerations:

• Run on an airgapped machine or a fresh Tails installation via USB with networking disabled
• Never share your seed phrase or private keys
• Store mnemonic backups securely in multiple physical locations
• SLIP39 shares should be distributed to different secure locations
• Use the digit format for metal plate backups or other durable storage
• Always verify reconstructed mnemonics match the original
• This tool is for educational and personal use only

🏗️ Architecture

The CLI consists of the following modules:

• tools.py: Core BIP39 and SLIP39 implementation

  • BIP39 class: Mnemonic generation, validation, splitting
  • SLIP39 class: Shamir Secret Sharing implementation

• cli.py: Command-line interface using Typer

  • deconstruct: Split mnemonics into parts/shares
  • reconstruct: Rebuild mnemonics from parts/shares

• test_tools.py / test_cli.py: Comprehensive test suites

  • BIP39 generation and roundtrip tests
  • SLIP39 share creation and reconstruction
  • CLI integration tests

📖 Examples

Secure Backup Strategy

1. Generate a 24-word BIP39 mnemonic
2. Split it into 2 parts (two 12-word mnemonics)
3. Convert each part to SLIP39 shares (2-of-3)
4. Distribute 6 total shares across secure locations
5. To recover, need 2 shares from each group (4 shares total)

# Deconstruct (outputs JSON)
interstellar deconstruct \
  --mnemonic "abandon abandon ... art" \
  --standard SLIP39 \
  --required 2 \
  --total 3 > shares.json

# Extract shares with jq
cat shares.json | jq -r '.shares'

# Reconstruct from file
interstellar reconstruct --filename backup_shares.txt --standard SLIP39

# Or from command line
interstellar reconstruct \
  --shares "share1,share2;share3,share4" \
  --standard SLIP39

🔒 Cryptotag Odin 7 Backup Guide

The Cryptotag Odin 7 is a titanium hexagonal prism system designed for SLIP39 backups. This guide explains how to use interstellar with Odin 7 for secure 24-word BIP39 seed storage.

Overview

A 24-word BIP39 seed is split into 2 wallet parts (12 words each), and each part is converted to 3 SLIP39 shares (20 words each). This creates 6 total shares that fit perfectly on 6 Odin hexagons, with 1 test hexagon for verification.

Store: Creating Shares with --digits

# Generate SLIP39 shares in digit format for metal engraving
interstellar deconstruct \
  --mnemonic "your 24 word seed phrase here..." \
  --required 2 \
  --total 3 \
  --digits

Output structure:

{
  "shares": [
    ["wallet1_share1 (20 digits)", "wallet1_share2", "wallet1_share3"],
    ["wallet2_share1 (20 digits)", "wallet2_share2", "wallet2_share3"]
  ]
}

Hexagon Face Layout

Each Odin hexagon has 6 faces. Here's how to engrave them:

┌───────────────────────────────────────────────────┐
│                 FACE 1: METADATA                  │
├─────────────────────────┬─────────────────────────┤
│  Total:  3                             Share:  1  │
│  Thresh: 2                             Wallet: 1  │
└─────────────────────────┴─────────────────────────┘

┌───────────────────────────────────────────────────┐
│                 FACE 2: WORDS 1-4                 │
├────────────┬────────────┬────────────┬────────────┤
│                                                   │
│  1: [----]    2: [----]    3: [----]    4: [----] │
└────────────┴────────────┴────────────┴────────────┘

┌───────────────────────────────────────────────────┐
│                 FACE 3: WORDS 5-8                 │
├────────────┬────────────┬────────────┬────────────┤
│                                                   │
│  5: [----]    6: [----]    7: [----]    8: [----] │
└────────────┴────────────┴────────────┴────────────┘

... (Faces 4-6 continue pattern through word 20)

Restore: Reconstructing from Shares

To recover your seed, you need 2 shares from each wallet part (4 shares total).

1. Create a file shares.txt with your digit shares (comma-separated within each wallet group, one group per line):

123 456 789 ... 20 digits, 234 567 890 ... 20 digits
345 678 901 ... 20 digits, 456 789 012 ... 20 digits

Line 1 contains 2 shares from wallet 1, line 2 contains 2 shares from wallet 2.

2. Reconstruct:

interstellar reconstruct --filename shares.txt --digits

Security Notes

• Store each hexagon in a different physical location
• With 2-of-3 threshold, losing 1 hexagon per wallet part is recoverable
• The test hexagon can verify your engraving is correct before distributing

📚 Dependencies

• hdwallet: HD wallet generation and derivation (subdependency of slip39)
• mnemonic: BIP39 mnemonic implementation
• slip39: SLIP39 Shamir Secret Sharing
• typer: Modern CLI framework

📄 License

MIT License — see LICENSE for details.