Wallet Backup Standards: SLIP-39 and 24-Word BIP-39, with a Passphrase

There are two standards for backing up a wallet, and this site recommends either — with a passphrase. This guide is the doing: how to create each on a Trezor, how to add the passphrase both must carry, and — for experts — the command-line path to the 33-word shares that Trezor Suite doesn’t offer. Everything here is universal in principle; the click-paths are Trezor’s (the site’s recommended hardware), current as of mid-2026.

The Two Standards, in One Paragraph Each

24-word BIP-39 is one secret: 24 words, 256-bit strength, restorable on virtually every wallet ever made. Its weakness is that it is one secret — the copy that burns was your only copy, and the copy a thief finds is the complete key. It suits a holder with a passphrase and two good storage locations.

SLIP-39 (Shamir) multi-share replaces the single secret with a threshold — say 2-of-3 shares in three places. No single fire, burglary, or seizure loses or leaks anything: below the threshold, a share reveals nothing. Its trade-offs: restores only on SLIP-39-capable wallets (Trezor, Keystone, and select others), and Trezor Suite creates 20-word (128-bit) shares — the 33-word (256-bit) version is command-line only (the expert path below).

Same lock, different key-storage plans. Both take the passphrase, and the passphrase is not optional in this house: it is the one credential that exists only in your head — the layer no seizure of artifacts can reach.

Before You Start — Read This Twice

Creating a backup creates a new wallet. You cannot re-backup an existing seed into a new format — you create the new wallet, then move funds to it. So this procedure belongs at one of two moments: a fresh device before first funding, or a deliberate migration. Never wipe or reset a device holding the only access to funds.

Have ready: the Trezor, pen and paper (metal comes later), an hour of unhurried time, and your storage locations already decided.

Path A — SLIP-39 Multi-Share in Trezor Suite

1. Open Trezor Suite and begin device setup (new device, or Settings → Device → Factory reset first — see the warning above).
2. At the backup-type choice, select Multi-share Backup. It is the default on Safe-series devices.
3. Choose your scheme: how many shares exist, how many recover. 2-of-3 is the workhorse; 3-of-5 for more locations or people.
4. The device displays each share, one at a time — write each on its own sheet of paper. The words never touch the computer; only the device screen shows them.
5. Verify each share when the device prompts re-entry.
6. Distribute: each share to a different physical location, per the split-location rule. Never store two shares together — two shares in one drawer is the single point of failure you just paid 33 minutes to eliminate.

Path B — 24-Word BIP-39 in Trezor Suite

1. Begin device setup as above.
2. At the backup-type choice, open the advanced/other options and select the 24-word Backup (menu wording varies slightly by device and Suite version; on some setups the 20-word single-share is the default you must click past).
3. Write the 24 words on paper from the device screen, verify when prompted.
4. Store per the Seedphrase page’s methods — metal beats paper, and two locations beat one, but remember each full copy is a complete key.

Both Paths — Now the Passphrase

The backup protects the seed’s artifacts. The passphrase protects what no artifact contains — and it works identically on top of either standard:

1. In Trezor Suite: Settings → Device → Passphrase — enable it.
2. At the next unlock, choose to enter a passphrase; entering one opens that passphrase’s wallet. Your standard (no-passphrase) wallet remains as the decoy tier; the passphrase wallet is the vault.
3. The rules, absolute: the passphrase is never typed into anything that isn’t the wallet flow, never stored digitally, never written where a seed backup lives. It exists in your head — and in your estate plan’s letter, by location reference only.
4. Send a small test amount to the passphrase wallet, then practice unlocking it from cold — twice. A passphrase you fumble under stress is a decoy that failed backwards.

Every different passphrase opens a different, equally valid wallet — there is no error message, and no way to prove a hidden wallet exists. That property is the entire duress and seizure defense; treat the exact spelling (including capitals) as sacred.

The Practice Restore

A backup that has never restored anything is a hope. Before funding for real: wipe the device (or use a second device), restore from your shares or words, enter the passphrase, and confirm the same addresses appear. One dry run converts the whole plan from theory to fact — while the stakes are still zero.

Write Yourself the Runbook

The machine you just configured will not forget any of this. You will. Returning after a year or three to repeat a procedure is where people improvise, and improvisation is where self-custody losses live. Unlike AI, humans need notes — so write them, using the design rule that makes notes safe:

Separate the choreography from the secrets. Secrets have exactly two homes — metal (seed, shares) and your head (passphrase, PIN) — and never get a third. Everything else about your setup is procedure, and procedure is safe to write down, because procedure is what a public security guide already is. This page describes the entire architecture to strangers and endangers no one.

The test for every line: would a burglar reading it learn anything a public guide wouldn’t teach?

• Safe to write: which device and standard (“Trezor, SLIP-39 2-of-3”), menu paths, the restore procedure, which accounts exist and their 2FA types, the bookmark list, revocation steps, and a dated rehearsal log (“2026-07: practice restore OK, ~40 min”).
• Never write, anywhere: seed words, the passphrase, PINs, exact share locations in plain language — and, the subtle one, the existence of your passphrase wallet in notes kept at home. The estate letter must say the vault exists (or your heirs recover only the decoy) — but that letter lives with your estate documents, not in your desk. Home notes instead say “restore per this guide” — a public pointer that reminds you of everything and reveals nothing personal.

Two tiers, like everything else in this architecture:

1. The open runbook — procedures, settings, rehearsal log, pointers to public guides. No secrets, no treasure map: it can live on your everyday computer or printed in a drawer. This is the document that rescues you after the hiatus.
2. The closed appendix — share locations and scheme details. One sheet, stored with your estate documents, referenced from the open runbook only by where it lives.

Last: notes decay unless rehearsed. The yearly practice run keeps the runbook truthful, and the runbook keeps the practice run at forty minutes instead of a panicked weekend. They maintain each other — schedule them together (tax season pairs well, per the inheritance guide).

The Expert Path — 33-Word Shares via the Command Line

First, the rule that gates this section: security has to be executable in a sustainable way — by you, tired, under stress, years from now. Too complicated is less safe. Most self-custody losses are self-inflicted, and a setup you can’t confidently restore is a weaker one than a simpler setup done perfectly. If the standards above fit you, they are not the lesser choice — they are the sustainable one. Enter this path only if you’ll rehearse it like everything else.

Trezor Suite creates 20-word (128-bit) SLIP-39 shares only. The SLIP-39 standard also defines 33-word (256-bit) shares — multi-share and maximum entropy — and Trezor devices support creating them through trezorctl, Trezor’s official command-line tool.

Honest context first: Trezor’s stated position is that the elliptic-curve cryptography securing most chains targets ~128-bit security, so longer backups add no practical strength — that’s why Suite doesn’t offer this. The case for 33 words is engineering margin, not necessity: maximum headroom in the one component you’ll never rotate. Decide which argument you find persuasive; both are honest.

The procedure (per Trezor’s own guidance, January 2026):

1. Install trezorctl using Trezor’s official guides: Windows · macOS (Linux installs the same way via pip).

2. Connect a new or wiped Trezor — reset-device initializes a device; it must never be aimed at one holding funds.

3. Run:

   trezorctl reset-device -b shamir -t 256

   -b shamir selects SLIP-39; -t 256 sets 256-bit strength → 33-word shares (-t 128 would give Suite’s standard 20-word shares).

4. Follow the prompts: choose shares and threshold, and the device displays each 33-word share on its own screen — same write-verify-distribute discipline as Path A.

5. Open Trezor Suite normally and enable the passphrase exactly as above — it stacks on this backup the same way.

6. Do the practice restore before funding. Suite’s recovery flow accepts 33-word shares even though its creation flow doesn’t offer them.

Sourced from Trezor’s official forum guidance and trezorctl documentation (January 2026). As with any expert path: verify it yourself, end to end, on a device holding nothing — an expert is someone who tests before trusting.

Everything on this page is universal — send anyone the link — pointing people to the source beats forwarding copies (a file passed around is exactly what this site warns about; the address stays canonical and current). For the curious: this site documents Actuator.Finance on PulseChain — the one-page version is How It Works, and Start Here picks your path.