Transferring a domain from one registrar company to another commonly involves the use of a unique authorization code, which different companies call an EPP authentication code, a domain name password or an Auth code. This code can be used as a protection measure against unapproved transfer attempts with all gTLD and with most ccTLD extensions. It can be obtained only by the domain owner and is provided by the current registrar company. It must be given to the new registrar company because the transfer process cannot be started without it. The code is case-sensitive and usually includes digits and special symbols, so as to prevent unauthenticated people from breaking it. Certain companies even change the codes of domains registered through them after a given period of time for greater security.