SLIP-39
SLIP-39 is a backup standard that splits a wallet's master secret into several word lists, of which a chosen number is needed to restore the wallet.
What Is SLIP-39?
SLIP-39 is a standard for splitting a wallet's master secret into several word lists, called shares, so that a chosen number of them is needed to restore the wallet. It was published by SatoshiLabs, the company behind Trezor, and applies Shamir's Secret Sharing to wallet backups.
The user picks a threshold and a total, for example 2 of 3 or 3 of 5. Each share is 20 or 33 words long, taken from a 1,024-word list that is different from the BIP39 list. Any set of shares that reaches the threshold rebuilds the secret; fewer shares reveal nothing about it. The standard also allows shares to be organised into groups and supports an optional passphrase.
The gain is that no single sheet of paper or metal plate is a single point of failure: one share can be lost or stolen without losing or exposing the funds. The cost is more locations to manage and a more involved recovery.
SLIP-39 is not compatible with BIP39. A SLIP-39 backup cannot be converted into a 12- or 24-word BIP39 phrase for the same wallet, so it can only be restored on wallets that implement the standard. Trezor Safe 3, Trezor Safe 5 and Trezor Safe 7 support it, as does the Keystone 3 Pro.
Shamir Secret Sharing (SSS) divides a secret, like a crypto wallet seed, into multiple shares. A threshold number of shares reconstructs it, enhancing security as in SLIP-39 backups.
Read full definition: Shamir Secret SharingTrezor is a hardware wallet by SatoshiLabs. It stores private keys offline to secure cryptocurrencies.
Read full definition: TrezorA backup in cryptocurrency is a secure copy of a wallet's seed phrase or private keys. It enables recovery of funds if the original wallet is lost or damaged.
Read full definition: BackupBIP39 is a standard for generating mnemonic seed phrases that are used to create deterministic wallets and securely back up cryptocurrency private keys.
Read full definition: BIP39A passphrase is an additional security layer for cryptocurrency wallets, acting as a 25th word in the BIP39 seed phrase, protecting access to hidden wallets.
Read full definition: PassphraseRecovery is the process of restoring access to a cryptocurrency wallet using its seed phrase or mnemonic backup if the original wallet is lost or inaccessible.
Read full definition: RecoveryReal-World Examples
Example 1: A Trezor Safe 5 user creates a 2-of-3 backup and keeps one share at home, one in a bank deposit box and one with a sibling. A burglar who finds the share at home cannot restore the wallet with it.
Example 2: A flood destroys one of three shares. The owner restores the wallet from the two that remain and then moves the funds to a new wallet with a fresh set of shares.
Example 3: Someone tries to restore a 20-word backup on a device that accepts only BIP39 phrases. The words are rejected, and the restore succeeds only on a wallet that supports SLIP-39.
A backup in cryptocurrency is a secure copy of a wallet's seed phrase or private keys. It enables recovery of funds if the original wallet is lost or damaged.
Read full definition: BackupBIP39 is a standard for generating mnemonic seed phrases that are used to create deterministic wallets and securely back up cryptocurrency private keys.
Read full definition: BIP39Shamir Secret Sharing (SSS) divides a secret, like a crypto wallet seed, into multiple shares. A threshold number of shares reconstructs it, enhancing security as in SLIP-39 backups.
Read full definition: Shamir Secret SharingFrequently Asked Questions
Can I convert a SLIP-39 backup into a 24-word phrase?
No. A SLIP-39 backup cannot be converted into a 12- or 24-word BIP39 phrase for the same wallet. Its shares are 20 or 33 words from a separate 1,024-word list, so the backup can only be restored on wallets that implement the standard. A device that accepts only BIP39 phrases will reject the words.
What do 2-of-3 and 3-of-5 mean in a SLIP-39 backup?
The first number is the threshold, the second the total number of shares. In a 2-of-3 backup any two shares rebuild the wallet, so one share can be lost or stolen without losing or exposing the funds. The price is more locations to manage and a more involved recovery.
What should I do after one SLIP-39 share is destroyed?
Restore the wallet from the shares that remain, as long as they reach the threshold, and then move the funds to a new wallet with a fresh set of shares. That way the backup is back to full strength, and a lost share no longer belongs to a set that controls money.
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