Cryptocurrencies work on the basic cryptographic principle of public-key and private key pairs that enables people to accept and send transactions. Public-keys can be thought of like a username of the email-id, available for everyone to see and send cryptocurrency. Whereas, private-keys are known only by the user (kind of like a password) and help the user to authorize the transaction. But when it comes to recovery, unlike passwords, private keys cannot be regenerated to regain access to the funds/accounts.