A private key, also known as a secret key, is used in cryptography, similar to a password. Just like your bank PIN, it's important to keep your private keys safe! Store them offline somewhere safe. Private keys are your string of alphanumeric characters that gives you access to your funds. With cryptocurrencies, private keys are also used to sign transactions. All transactions are signed locally by users using their private keys (as opposed to Cogni signing transactions on behalf of users). This means that even if we wanted to steal your digital assets — we can't!