Worried about the security of your Bitcoin wallet? Let’s break down the power of your wallet’s passphrase and why it matters in ensuring your cryptocurrency stays safe. What is a BIP39 Passphrase? Your Bitcoin wallet is protected by 24 seed words that provide 256 bits of entropy—a measure of security complexity. However, these are at risk if they’re exposed. To add an extra layer of security, we use the BIP39 passphrase, often called the ‘25th-word.’ It acts as a 2nd-factor authentication (2FA) for your Bitcoin wallet.