Entropy

Entropy is a measure of unpredictability. In cryptography and crypto wallets, it describes how random a number is. More entropy means less guessable outcomes, which is what keeps keys and wallets safe.

Entropy in cryptography

Cryptography relies on hard-to-predict numbers. Entropy expresses that unpredictability, so ciphers and keys cannot be guessed. In practice, systems try to gather enough randomness before creating keys or performing secure operations.

How wallets use entropy

When you set up a wallet, the software generates a very large random number. That number is the wallet’s entropy, and it becomes the root that all your keys grow from. Wallets typically show a human-readable version of that same randomness as a “secret recovery phrase” or seed phrase.

Seed phrases and BIP-39

The widely used BIP-39 standard turns raw entropy into words from a fixed list. As a rule of thumb, 128-bit entropy maps to a 12-word phrase, and 256-bit entropy maps to 24 words. Both represent the same underlying randomness, just in different formats.

Why entropy quality matters

Weak or predictable entropy can produce overlapping seeds or keys that an attacker can brute-force. Good entropy makes regenerating the same value statistically infeasible, which is why wallets focus on generating high-quality randomness before deriving keys.

Where entropy comes from

Systems pull randomness from unpredictable events. Examples include operating-system inputs like mouse movement or timing interrupts, as well as other noisy physical processes. Hardware and software random number generators combine these signals to create strong entropy for cryptographic use.

Wallet generation flow

Most wallets call a random number generator to produce entropy, convert it into a seed phrase using BIP-39, then derive the private keys and addresses used for your accounts. The seed is your backup because it encodes that original entropy.

Bits of entropy and real-world security

Higher bit counts increase the search space that an attacker would need to try. Well-generated 12-word phrases provide 128 bits of entropy, which is already far beyond practical brute-force limits for consumer wallets. Longer phrases add more margin but do not change the basic process.