Transferring a domain from one company to another usually involves the use of a unique transfer code, which different registrar companies refer to as an EPP key, a domain name password or an AuthInfo code. This code can be used as a protection measure against unsanctioned transfer attempts with all gTLD and with most ccTLD extensions. The code can be obtained only by the domain registrant and is provided by the present registrar. It must be given to the new domain registrar company because the transfer process cannot be started without it. The code is case-sensitive and traditionally contains digits and special symbols, so as to impede unauthorized persons from breaking it. Some companies even change the codes of domain names registered through them after a certain interval of time for better safety.