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How Frag-ment works.

From a simple idea to mathematical certainty. Here's the full picture.

The big picture

One secret. Many pieces.
No single point of failure.

A seed phrase is a 12 or 24 words sequence that controls everything. Lose it, your funds are gone. Have it stolen, someone else controls your funds. One sheet of paper, one cloud backup, one piece of metal: all share the same flaw, a single point of failure.

Frag-ment splits your seed phrase into multiple fragments, mathematically bound together. You decide how many fragments to create and how many are needed to reconstruct the original. Each fragment, alone, reveals nothing.

seed phrase
Frag-ment
A3 F7 2C 8E1B 9D 4F 6AC8 02 E5 7B
5E D1 8A 3FB4 6C 0E 927D A9 51 C3
F2 38 4B 1D9A 67 E0 5C3F 84 B2 6E
xf(x)12345 SECRET F1F2F3F4F5
3 of 5 fragments used
not needed
The math

Shamir's Secret Sharing.

In 1979, cryptographer Adi Shamir solved a fundamental problem: how do you split a secret so that no single piece reveals anything, but enough pieces together reveal everything? His answer was a mathematical scheme based on polynomial interpolation. Any M fragments reconstruct the original. Any fewer and the secret remains completely out of reach, not by luck, but by mathematics.

Frag-ment uses SLIP39, a Web3 standard created by SatoshiLabs in 2013, also implemented by hardware wallets like Trezor. Each fragment becomes a sequence of words, easy to write down or store on a NFC card.

We don't roll our own cryptography. SLIP39 has been audited and reviewed by the security community since 2017.

Read the SLIP39 specification →
M of N schemes

You decide the threshold.

Choose how many fragments to create and how many are needed to reconstruct. From a simple 2-of-3 for everyday peace of mind to a 5-of-7 for institutional-grade redundancy. Every threshold is mathematically valid.

3 fragments required 2 unused
seed phrase
Frag-ment app F1F2F3F4F5 Frag-ment app
seed phrase

Example of a 3-of-5 scheme. Five fragments are created, only three are needed to reconstruct the seed phrase.

2/3

Personal use

Three fragments, any two reconstruct. Simple, resilient, ideal for everyday peace of mind.

3/5

Family redundancy

Five fragments distributed across trusted locations and people. Survives multiple losses without compromising security.

5/7

Institutional

Seven fragments, five required. Maximum redundancy for high-value or shared-control scenarios.

Groups

Structure trust the way it actually works.

Real-world trust isn't flat. You may trust your closest family fully, your siblings partially, and a notary professionally. You want each circle to play a different role in recovering your seed.

Frag-ment lets you organize fragments into groups. For example: a family group of three fragments where any two reconstruct, combined with a notary group of one fragment that must be present. Reconstruction requires the rules of every group to be met.

Group-based reconstruction is part of the SLIP39 standard.

seed phrase FAMILY 2 of 3 PARTNER CHILD SIBLING INSTITUTIONAL 1 of 2 NOTARY LAWYER
fragments used
not needed
Storage

Store each fragment where it makes sense.

Different fragments belong in different places. Frag-ment supports multiple storage formats so you can match each fragment's location to its risk profile and role.

NFC cards

Tap-to-read secure NFC cards. Compact, discrete, and physically unalterable once written. Ideal for fragments meant to be hidden or carried.

Paper backup

Print fragments as words or QR codes for long-term archiving. No batteries, no software dependency, no obsolescence. Paper outlives most digital formats.

Mobile vault

Store a fragment encrypted on your phone via the mobile app. Always with you, fully offline.

Online vault

Encrypted online storage for one fragment, with conditional access rules. Convenience without compromising the principle: useless on its own, like every fragment.

Notary deposit

Entrust a sealed fragment to a notary or legal professional. Institutionally recognized, legally binding, and completely independent from any digital infrastructure.

Desktop vault

Store a fragment directly within the Frag-ment application on your computer. Encrypted locally, never uploaded, accessible only on your machine.

Mobile
Paper
Notary
Frag-ment
seed phrase
Reconstruction

When you need it back.

Recovery is the reverse of fragmentation. Bring the required number of fragments together (physically or digitally) into Frag-ment, and the original seed phrase is reconstructed locally, on your device, in seconds.

The seed exists in memory only long enough to be displayed or transferred to your wallet, then is securely wiped. Nothing is logged, nothing is sent, 100% offline.

Frag-ment & hardware wallets

Your hardware wallet protects access.
Frag-ment protects continuity.

Hardware wallets like Ledger or Trezor protect your seed phrase during transactions. They keep your keys offline and prevent attackers from extracting them. They are excellent at what they do.

But hardware wallets don't solve what happens when the seed itself is lost, destroyed, or unreachable (by accident, by natural disaster, by death). That's a different problem, and it requires a different tool.

Frag-ment is not a replacement for your hardware wallet. It's the missing layer that ensures your seed phrase can survive loss, time, and your own absence, without ever giving up non-custodial control.

Now you understand. Try the tool.