Seed Phrase

A seed phrase (mnemonic phrase) is a short list of words that can recreate every private key in a cryptocurrency wallet, enabling secure backup and recovery.

Overview#

Seed phrases consist of 12, 18, or 24 words drawn from a 2048‑word dictionary defined by the BIP‑39 standard..

When a new wallet is created, the algorithm randomly picks words from this list and uses the resulting phrase to generate a hierarchically deterministic (HD) master key. This master key can then derive an unlimited number of private and public keys for transactions.

Generation Process#

Random selection – the wallet generates a random sequence of words from the BIP‑39 list.
HD master key creation – the seed phrase is hashed (SHA‑512) to produce a master private key..
Key derivation – using BIP‑32 and BIP‑44, the master key derives child keys for multiple addresses..

Use in Wallets#

Non‑custodial wallets

These wallets store the seed phrase locally, giving users full control and full responsibility for security.

Tonkeeper – a TON‑specific wallet that supports BIP‑39 mnemonics.
MetaMask – an Ethereum‑focused wallet that also follows BIP‑39.
Trust Wallet – a multi‑chain wallet using BIP‑39 for key generation.

Custodial wallets

Exchanges and other services keep the seed phrase on behalf of the user. Access is typically granted via a username/password, which is convenient but reduces user control and increases risk.

Technical Details#

Hashing – the seed phrase is processed with SHA‑512 to create a unique hash.
Master key – the hash becomes the master private key, the root of all subsequent keys.
Derived keys – protocols BIP‑32 and BIP‑44 generate a hierarchy of private and public keys, allowing many addresses from a single seed phrase.

Safety Recommendations#

Physical security – store the written phrase in a safe or other secure offline location.
Avoid digital copies – do not keep the phrase on internet‑connected devices to prevent cyber‑theft.
Backups – create multiple copies and keep them in separate secure places to mitigate loss.

Restoring Access#

Enter the seed phrase into a wallet that supports BIP‑39.
The wallet verifies the phrase and regenerates the master key.
All assets linked to the derived keys become accessible again.

Potential Risks#

Loss – without a backup, a lost seed phrase results in irreversible loss of assets.
Compromise – if an attacker obtains the phrase, they can control the wallet and transfer funds.

Compatibility#

Because BIP‑39 is a universal standard, the same seed phrase works across any wallet that implements the standard, allowing seamless migration between applications.