Setup guide
Your bitcoin key. In five steps.
Fully offline. No software required. No trust required.
Quick start
- 1 Assemble — Randomly insert bits to create your unique binary sequence
- 2 Convert — Read bits offline to derive your BIP-39 seed phrase
- 3 Backup — Create multiple secure copies before proceeding
- 4 Protect — Store in steel case, add a passphrase for maximum security
- 5 Use — Generate addresses using any offline signing tool
Step 1
Make Your Key
Randomly insert the physical bits into your key's eight slots. Each bit reads as either 0 or 1 depending on its orientation — creating the binary foundation of your Bitcoin private key.
Understanding Your Key
Your key has eight numbered faces (0–7), each containing bit positions:
- 256-bit key: 32 bit positions per face
- 128-bit MINI key: 16 bit positions per face
Choose Your Reading Order
Before inserting bits, decide your reading order — this determines your unique private key.
Step 2
Convert to Seed Phrase
Using pen and paper only — remain offline throughout this process.
- Starting at your most significant digit, read 11 consecutive bits
- Optional: convert those 11 bits to a decimal number (0–2047)
- Find the corresponding word in the BIP-39 wordlist
- Repeat for a total of 11 words (128-bit) or 23 words (256-bit)
You'll have a small number of bits remaining after the last full word. The final word incorporates these plus a checksum. Use an offline tool — such as SeedSigner or an offline calculator — to derive the complete seed phrase with the correct checksum word.
Step 3
Backup Your Key
Your key is your only access to your Bitcoin. Create redundant backups before proceeding — no exceptions.
Physical Key Backups
Purchase additional Modulo Keys and assemble them identically, or document bit positions on durable material stored separately from your primary key.
Seed Phrase Backups
Write your seed phrase on metal plates or waterproof paper. Store copies in geographically separate, secure locations.
Distributed Security
Consider multi-signature setups or splitting backup information among trusted parties to eliminate single points of failure.
Step 4
Protect Your Key
Physical Protection
- Store your Modulo Key in the included stainless steel case
- Keep in a fire-resistant safe, preferably bolted down
- Store backups in separate geographic locations
- Never photograph or discuss your key or its configuration
Add a Passphrase
A BIP-39 passphrase (the “25th word”) adds a critical second layer. Even if someone obtains your physical key or seed phrase, they cannot access your Bitcoin without it.
Operational Security
- Maintain privacy about your Bitcoin holdings
- Document key details using only language that you alone understand
- Consider a decoy wallet for home security scenarios
Step 5
Use Your Key
Load your seed phrase into any offline signing tool to generate Bitcoin addresses and sign transactions — without ever exposing your key to an internet-connected device.
- Generate Bitcoin receiving addresses
- Sign transactions air-gapped
- Maintain complete sovereignty over your funds
Recommended tools: SeedSigner, Coldcard, Sparrow Wallet (watch-only with air-gap). Any BIP-39 compatible wallet works. Your Modulo Key is not tied to any proprietary software.
