If we continue the analogy with messaging, the private key allows access to the full functionality of the address Ethereum, just as the password allows access to the mailbox to view and send messages. The private key is randomly generated by a computer program at the first initialization of a portfolio, and is then derived to produce the Public Key and the different Ethereum addresses. It is in the form of an alpha-numeric character string. Just like messaging clients that allow password recovery in case of loss, the Ethereum network offers security as a mean of recovering the private key, such as generating a SEED at initialization. If its security was not in place when the private key was lost, then the funds will be considered lost as inaccessible.