How Is a Bitcoin Private Key Generated?

A Bitcoin private key is essentially a large, random number, typically a 256-bit number. It is generated by a cryptographically secure pseudo-random number generator (CSPRNG).

The quality of the randomness is paramount; if the number is not truly random, the private key could be guessed, leading to the theft of funds. The number is usually represented as a sequence of letters and numbers or as a 12- or 24-word seed phrase (BIP-39).