Basics
Basic concepts of cryptocurrency security
Seed Phrase
A set of 12 or 24 words from which all wallet keys are generated. The main secret that needs to be protected.
Synonyms: mnemonic phrase, recovery phrase, backup phrase
BIP39
Standard for generating mnemonic phrases from a dictionary of 2048 words. Defines how 12 or 24 words are converted into a cryptographic key.
Entropy
A measure of randomness. The higher the entropy, the harder it is to guess. 12 words = 128 bits, 24 words = 256 bits.
Private Key
A secret number that allows you to control cryptocurrency. Generated from the seed phrase. Never share it!
Cold Wallet
A device for storing cryptocurrency that is not connected to the internet. Examples: Ledger, Trezor, Coldcard.
Hot Wallet
A wallet connected to the internet. Convenient but less secure. Examples: MetaMask, Trust Wallet.
Common Questions
Without the seed phrase, it is impossible to recover access to your cryptocurrency. This is irreversible — no one can help. That's why it's critically important to securely store a backup.
No. Any device connected to the internet can be hacked. Seed phrases should only be stored offline: on paper, metal, or in a hardware wallet.
24 words provide maximum security (256 bits of entropy). 12 words (128 bits) are sufficient for most cases, but 24 are recommended for large amounts.
No. A seed phrase must consist of words from the BIP39 dictionary (2048 words) and include a checksum. Homemade phrases won't work or will be insecure.
A passphrase (25th word) is an additional password to the seed phrase. Not mandatory, but adds protection: without it, even knowing 24 words won't give access to the wallet.
Start with a passphrase — it's simple and supported by all wallets. As your holdings grow, you can add metal storage and consider Shamir.