Transferring a domain from one company to another commonly involves the use of a special authorization code, which different registrar companies call an EPP key, a domain password or an Auth code. This code can be used as a safety mechanism against unsanctioned transfers with all gTLD and with most ccTLD extensions. It can be obtained only by the owner of the given domain and is issued by the present registrar. It must be given to the new domain name registrar company because the transfer process cannot be started without it. The code is case-sensitive and traditionally comprises of digits and special symbols, so as to hinder unauthenticated persons from hijacking it. Certain domain registrars even alter the codes of domains registered through them after a given amount of time for greater security.