MMGen Wallet: A Secure Online/Offline Cryptocurrency Wallet for Command Line Users

Introduction

MMGen Wallet is a robust command-line cryptocurrency wallet that combines online convenience with offline security. Designed for Bitcoin and select altcoins, this Python-based solution provides cold storage capabilities while maintaining full functionality for tracking and transacting with your digital assets.

Key Features:

Air-gapped security: Private keys never touch internet-connected devices
Multi-coin support: Works with Bitcoin, Ethereum, Litecoin, and more
Flexible seed storage: Multiple secure formats including mnemonics and encrypted files
Advanced privacy: No internet calls or data leaks to third parties

Core Functionality

Dual-Machine Architecture

MMGen Wallet operates across two systems:

Online Computer:
- Tracks balances
- Creates unsigned transactions
- Broadcasts signed transactions
Offline Machine (typically Raspberry Pi):
- Generates wallets and addresses
- Signs transactions
- Stores seeds securely

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Security Protocol

The wallet's security model ensures:

Zero network exposure for private keys
Deterministic address generation from a single seed
Multiple encryption options for seed storage
Physical separation of sensitive operations

Unique Technical Features

Simplified Key Derivation

Unlike BIP32-based wallets, MMGen uses:

Non-hierarchical hash-based derivation
Easier key recovery without proprietary software
Support for both Electrum and BIP39 mnemonics

Comprehensive Asset Support

Feature	Supported Assets
Full tracking	BTC, BCH, LTC, ETH, ETC
Address gen	144+ altcoins including Zcash
Token support	ERC20 tokens
Special features	Monero wallet management

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Advanced Capabilities

Transaction Management

Coin control for anonymity
BIP69 ordering to obscure transaction patterns
Customizable fees with RBF support
Autosigning for convenient cold storage access

Wallet Flexibility

9 distinct wallet formats
XOR seed splitting (N-of-N)
Subwallets for hot/cold separation
Human-readable backup options

Platform Support

MMGen Wallet runs on:

Linux
macOS
Windows (via MSYS2)

Getting Started

Installation Guide

Clone the repository from GitHub
Install Python dependencies
Configure your online/offline machines
Initialize your first wallet

Basic Commands

mmgen-walletgen   # Create new wallet
mmgen-addrgen     # Generate addresses
mmgen-txcreate    # Build transactions

FAQs

Is MMGen Wallet suitable for beginners?

While powerful, the command-line interface has a learning curve. Beginners should familiarize themselves with basic terminal usage before proceeding.

How does offline signing work?

Transactions are created online, transferred via USB/SD card to the offline machine for signing, then returned to the online machine for broadcasting.

What makes MMGen different from Electrum?

While both support offline signing, MMGen offers:

More coin support
Alternative key derivation
Additional storage formats
No reliance on third-party servers

Can I use MMGen with hardware wallets?

Currently, MMGen operates as a standalone solution without hardware wallet integration.

How secure are the mnemonic phrases?

Extremely secure, using either:

The original Electrum wordlist (1626 words)
Standard BIP39 wordlist (2048 words)

Community and Support

Development Resources

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Security Best Practices

Always verify downloads via PGP signatures
Maintain regular backups of your seed
Use dedicated hardware for offline operations
Consider seed splitting for additional protection
Never store seeds digitally on internet-connected devices