Have you ever lost your crypto because of a lost recovery phrase… That’s the nightmare nobody wants.
And sadly, it happens.
I’ve seen people online admit they forgot a single seed phrase. Some lost access to life-changing amounts of money. Hence, millions gone, and this is all because of one slip.
That’s why you need Shamir Backup.
It’s a method that splits a wallet’s seed phrase into multiple parts. I’m going to walk you through what Shamir backup is, how it works, the pros and cons, and whether it makes sense for you.
Well, Shamir Backup is different from a single backup in a few key ways:
- Word Count: Shamir shares are 20 or 33 words long, while single backups are 12 or 24 words.
- Word List: They use a different word list, so you won’t see the same words in a Shamir share that you would in a regular BIP39 backup.
- Redundancy: Shamir allows for redundancy. You can lose a share (up to your set threshold) and still recover your wallet.
Shamir Backup Splits Your Seed Into Shares
Shamir backup, sometimes called Shamir’s Secret Sharing (SLIP-39), mainly breaks your wallet’s recovery seed into several unique parts, known as shares.
Here, instead of having just one list of 12 or 24 words, you create up to 16 separate recovery shares; each share is around a 20 or 33-word phrase.
Then, you have to set a threshold… a minimum number of shares needed to access your wallet. So, for example, a 2-of-3 scheme means any two of the three shares can recover your wallet.
How it works
Here’s a simple way to think about it:
- Choose the number of shares and threshold: First, you need to decide how many parts you want (from 1 to 16) and how many must be combined to restore the wallet.
- Generate the shares: Your hardware wallet creates several 20- or 33-word recovery phrases. Each share looks like a mini seed phrase and contains part of the secret.
- Distribute the shares: Now, you keep some shares yourself and give others to trusted people or even store them in separate secure locations.
- Relax (sort of): The idea is that losing one share doesn’t lock you out. So, as long as you keep enough shares to meet the threshold, your crypto remains accessible.
Behind the scenes, Shamir backup uses a clever bit of math. The wallet treats your master seed as a point on a polynomial curve. It then generates several points on that curve; each point is one share.
Now, only when enough points are combined can the original curve (and the seed) be reconstructed. Also, without the required number of shares, any individual part reveals nothing about your private key.
Why Shamir Backup exists
You know, most of the people lose seed phrases because of memory lapses, theft, or physical disasters like fire and flood.
Even some crypto holders avoid writing down their seed at all, thinking they’ll memorize it, but memory can fail. Also, others make multiple copies and hide them, but more copies mean a higher chance that someone steals or discovers the seed.
The solution: Shamir backup offers a middle path… redundancy without exposing the full secret in one place.
Benefits and risks of using Shamir seed backup
Single Seed vs. Shamir Backup: A Simple Comparison
| Feature | Single Seed (BIP-39) | Shamir Backup (SLIP-39) |
|---|---|---|
| Word length | 12, 18, or 24 words | 20 or 33 words |
| Number of shares | One seed phrase | 1 to 16 shares |
| Threshold for recovery | All words needed | User-specified (e.g., 2-of-3, 3-of-5) |
| Distribution flexibility | None; one copy only | Shares can be split among trusted people/locations |
| Redundancy | None; losing the seed is fatal | Configurable; some shares can be lost without losing access |
How to Use Shamir Backup + With Trezor
The setup process is done through the Trezor Suite application and your Trezor device’s screen. Let’s see how to get started…
Connect and Start: Connect your Trezor device to your computer and open the Trezor Suite app. Now, make sure your device is ready and its firmware is up to date.
Note: Only Trezor Safe 5 and Model T support Shamir Backup; Safe 3 and Model One doesn’t.
Create a New Wallet: Next, if you’re setting up a new device, choose “Create new wallet”, and if you’re updating a wallet that’s already in use, you’ll need to use a different process, but for a fresh start, this is where you begin.
Choose Multi-share Backup: From the options, select “Multi-share Backup” (this is Trezor’s term for Shamir Backup). Then, click “Create wallet” and agree to the terms and conditions on your Trezor’s screen.
Set Your Scheme: You must know, this is the most important step. So, on your Trezor device, you will be prompted to choose your backup scheme.
You’ll set the total number of shares you want to create and the minimum number of shares (the threshold) required for recovery.
For instance: you could select 3 shares and a threshold of 2…
Write Down Your Shares: Your Trezor device will then display each unique share, one by one, and each share is a list of 20 words. Also, you must write these down precisely on the provided recovery cards.
Verify Your Backup: Now, as you’ve written down all the shares, Trezor Suite will prompt you to verify them. The device will ask you to re-enter a few words from different shares to confirm you’ve written them down correctly.
Set Your PIN and Complete Setup: At last, after verifying your shares, you’ll set a PIN to protect your device from physical access.
So, choose a strong, memorable PIN that you won’t forget, and once the PIN is set, you’ll complete the rest of the Trezor setup, and your wallet is ready to use with your new, secure Shamir Backup.
Who Should Consider Shamir Backup
Shamir backup makes sense for:
- High-Value Holders: Life-changing sums need redundancy.
- Multiple Locations or Custodians: Good for spreading risk.
- Business or Family Funds: Groups can set recovery thresholds.
- Tech-Comfortable Users: People willing to test and practice.
It might not be ideal for:
- Beginners with Small Holdings
- Individuals Who Live Alone
- People Already Using Multisig
Final Thoughts: Is Shamir Backup Right for You?
I’ll be honest. I was skeptical at first. Yes, Shamir backup sounded like something only crypto exchanges or corporate treasuries would use. But after researching and testing, I see its appeal.
Actually, it offers redundancy without revealing your full seed phrase, and it turns a catastrophic loss into a manageable setback. Still, it comes with complexity, additional cost, and a need to trust others.
But again, if you hold significant crypto or worry about natural disasters destroying your seed, Shamir backup gives peace of mind.
However, if your holdings are modest or you prefer minimalistic setups, you might be happier sticking to a single seed with a passphrase.
Read my other guides related: best crypto hardware wallets and best cold wallets.
Related FAQs
What if some recovery shares are missing or stolen?
Well, Shamir Backup is designed with redundancy. So, as long as you have enough shares to meet the minimum threshold you set – like, say, a 2-of-3 or 3-of-5 rule – your wallet can totally be restored.
A single lost or stolen share doesn’t really reveal your secret or compromise your crypto. You know, each share on its own is basically useless, so even if someone finds just one, they can’t access your funds unless they get enough pieces to meet your recovery rule.
What happens if too many shares are lost?
I mean, the system only works if you can meet that minimum threshold. For example, if you set a 3-of-5 rule, you absolutely have to have at least three shares to recover your wallet.
Now, if you lose more than that, the wallet becomes impossible to restore. This is why choosing the right threshold and storing your shares in a few different safe places is so important. Honestly, many people even test the recovery process beforehand, just to avoid any surprises and make sure they know exactly how many shares are needed.
Which wallets actually support Shamir Backup?
Shamir Backup isn’t available on every wallet out there. Right now, it’s mainly supported by a few hardware wallets that have implemented the SLIP-39 standard.
The most popular options are the Trezor Safe 5 and Keystone 3 Pro hardware wallets. These devices let you generate and restore Shamir backups directly on the device. Well, most of the other cold wallets still use the standard 12- or 24-word recovery seed, so if Shamir is a must-have for you, picking one of these supported wallets is the safest way to go. Also, read my Trezor wallet review.
How does Shamir’s secret sharing algorithm actually work?
The Shamir’s Secret Sharing algorithm works by using a clever mathematical formula to split a single private key into multiple unique pieces, or “shares.”
Here, no single share holds any meaningful information on its own, so it’s only when you combine the required number of shares – which you determined with your threshold – that the original private key can be reassembled. Well, you can think of it like a puzzle where you need a specific number of pieces to see the whole picture