Seed Phrase
Recovery phrase · Secret recovery phrase · Mnemonic · Mnemonic phrase · Backup phrase · Seed words
The 12 or 24 words a self-custody wallet shows at setup. Anyone holding them can rebuild the wallet, and take its coins, on any device.
Simple explanation
Background: Koreans call it 시드 문구 or 복구 문구 ("recovery phrase"). More Korean investors now move coins from exchanges to their own wallets, and impostors posing as exchange or wallet staff ask for these words, so it is worth knowing exactly what they unlock.
When you first set up a wallet app or hardware wallet, it shows 12 or 24 English words in order: the seed phrase. The wallet turns these words into private keys and the keys into addresses. One seed phrase generates the keys and addresses for many coins, bitcoin and ether among them, along fixed derivation paths, so it is the master key to every address in that wallet. Most wallets follow a common standard, BIP-39, so a phrase made in one wallet app usually restores the same addresses in another, though an app using a different path may show different addresses.
The words come from the BIP-39 list of 2,048 English words. Twelve words encode a 128-bit random number plus a 4-bit checksum; twenty-four words encode 256 bits plus an 8-bit checksum, cut into 11-bit pieces, one per word. Because the last word carries part of the checksum, twelve words picked at random are usually an invalid phrase. The number of combinations is far too large for anyone to guess, which is also why the order and spelling must be written down exactly. Some wallets let you add your own passphrase on top (often called the "25th word"); forget it and the seed phrase alone will not open the same wallet.
A seed phrase is not an app password. A password or PIN opens the wallet app on one device and is useless on a new phone; the seed phrase rebuilds the whole wallet on any device. Lose your phone and the phrase brings your coins back; keep your phone but let someone see the phrase and they can restore the wallet on their own device and move everything out. Blockchain transfers cannot be reversed and there is no password reset. Lose the phrase and the device, and nobody, not even the company that made the wallet, can recover the coins.
An account at Upbit, Bithumb or any other exchange has no seed phrase for you. Coins left on an exchange sit in wallets the exchange controls, and the exchange holds the keys. So no exchange employee, help desk, wallet company or token foundation has any reason to ask for a seed phrase, and anyone claiming to be the police or a financial regulator who asks for one is a scammer too. Any site, app or chat contact that wants your phrase to "verify your wallet", "sync your wallet", "claim an airdrop", "run a security check" or "fix a withdrawal error" should be treated as a scam. Korea's Financial Supervisory Service has issued a consumer alert about scammers posing as token-foundation staff who got victims to connect their wallets and then drained them.
The tricks vary: fake wallet apps with names and icons close to the real ones, fake wallet sites at the top of search ads, messages from "support", and second-hand or counterfeit hardware wallets that arrive with a seed phrase already printed on a card. A genuine wallet generates a new phrase itself when you set it up; a wallet built from a phrase someone else chose can be opened by that person too. Even without the phrase, connecting a wallet to an unknown site and approving (signing) its request can be enough to drain it, so approve a signature only after reading what it does.
The rule for storage is: nobody else can see it, and you cannot lose it. Screenshots, photos, cloud notes, messages to yourself and email can all leak if your phone or account is compromised. People write the words in order on paper and keep it somewhere safe from fire and water, or stamp them on a metal plate. After writing them down, go through the wallet's check (it asks for the word in a given position), and before putting in a large sum, restoring the wallet from the phrase confirms you copied it correctly. Many people also plan how their family would find where the phrase is kept, while never showing anyone the words themselves.
Korean exchanges make you register a personal-wallet address and prove the wallet is yours before withdrawing to it, and that process does not ask for your seed phrase either; anyone offering to "handle the registration" if you hand over the words is running a scam. The seed phrase has no direct link to the kimchi premium, but whenever coins pass through a personal wallet, for arbitrage or to keep a coin that an exchange is delisting, the phrase is that wallet's only key.
CoinGaja has no wallet features, so it never needs a seed phrase or private key. Before moving coins to a personal wallet, you can check on the deposit and withdrawal suspension page that withdrawals of that coin are open, and look for wallet or network notices in Exchange notices.
Example
12 words from a list of 2,048 → 2,048^12 = 2^132 combinations; those with a valid 4-bit checksum: 2^132 ÷ 16 = 2^128, about 3.4 × 10^38
Guessing 1 trillion a second → 3.4 × 10^26 seconds ÷ 31,536,000 seconds (a year) = about 1.08 × 10^19 years (about 10.8 quintillion years)
With 24 words → 2^256, about 1.16 × 10^77 combinations
Lose just 1 word whose position you know → of 2,048 candidates, about 2,048 ÷ 16 = 128 pass the checksum (only if the other 11 are exactly right)
Type the phrase of a wallet holding ₩20,000,000 (about $14,300) into a fake "wallet sync" site → once the attacker restores the wallet and moves the coins, the balance is ₩0, with no way back
※ Example numbers, for illustration only
See it on CoinGaja
Related terms
Comments · ask anything about this term
Comments
No comments yet.