OMDP39
A simple explanation of how OMDP39 helps protect your BIP39 wallet backup — even if something goes wrong.
When a BIP39-compatible wallet creates a new wallet, it generates a list of 12 or 24 random words. This list is your seed phrase. It's the only way to recover your wallet — and whoever has it controls your money.
Your seed phrase is the master key to a bank vault. If you lose the key, you lose access — forever. If someone else finds it, they can take everything. There's no "forgot password", no bank to call, no reset.
Most people write down their seed phrase on a piece of paper and hide it somewhere. That seems safe — but it creates a dangerous single point of failure.
Imagine your secret message is transformed into 5 puzzle pieces, each hidden in a different city. Even if a thief steals 2 pieces, they can't figure out anything. But when you collect any 3, the message appears perfectly. That's OMDP39 — backed by information-theoretic math.
You don't need to understand the math. The app does everything. Here's what happens:
Your 12 or 24 words are processed by OMDP39. This happens entirely in your browser — the seed never leaves your device.
Pick two numbers: total pieces (up to 31) and minimum needed to recover. Example: create 5 pieces, need any 3. This is called a "3-of-5" setup.
Every piece (called a "share") is output as 33 readable words. Easy to write on paper or stamp on metal — no technical knowledge needed.
Home safe, bank vault, family member, office. To recover later, just collect the minimum number and combine them — your original seed appears perfectly.
A typical 3-of-5 setup. Each share is stored in a different secure location:
Green = collected for recovery. That's 3 shares — enough! The bank could flood, the office could burn — doesn't matter. Any 3 of 5 works.
OMDP39 supports up to 31 shares with any threshold. Pick what fits your situation:
Higher threshold = harder for a thief but also harder for you. More shares = more redundancy but more places to secure. Most people find 3-of-5 is the perfect balance.
No hex codes, no technical output. Each share uses the same word dictionary as your wallet — easy to write down, easy to verify.
This isn't like a password that a supercomputer could eventually guess. With fewer than the required shares, recovering the secret is mathematically impossible — regardless of computing power.
Shares are generated with cryptographically secure random numbers. No patterns to exploit.
Each backup gets a unique ID. Shares from different wallets can never be mixed.
Built-in checksums detect accidental typos with very high probability before recovery.
With 2 shares in a 3-of-5 setup, billions of seeds are equally possible. No computer can narrow it down.
OMDP39 implements Shamir's Secret Sharing over the finite field GF(2¹¹), mapping perfectly to BIP39 word indices (0–2047 = 11 bits per word). A random polynomial of degree t-1 is constructed with the secret as its constant term. Shares are evaluations at distinct non-zero points. Recovery uses Lagrange interpolation. Security is information-theoretic — it does not rely on any computational hardness assumption. The protocol supports up to 31 shares with configurable thresholds.
Use the OMDP39 Tool to split, restore, and verify your BIP39 seed backup locally in the browser.
Open the OMDP39 Tool