Transferring a domain from one company to another commonly involves the use of a unique domain authorization code, which different companies refer to as an EPP authorization code, a domain name password or an Auth-Info code. This code can be used as a security mechanism against unsolicited transfer attempts with all gTLD and with most ccTLD extensions. It can be obtained only by the owner of the particular domain name and is provided by the present domain name registrar company. It must be given to the new domain name registrar company because the transfer cannot be initiated without it. The code is case-sensitive and often contains digits and special symbols, so as to stop unauthenticated persons from cracking it. Some domain name registrars even change the codes of domains registered through them after a given amount of time for better security.