Transferring a domain from one company to another usually involves the use of a unique transfer code, which different companies call an EPP key, a domain name password or an Auth code. This code can be used as a protection mechanism against unwanted transfer attempts with all gTLD and with most ccTLD extensions. It can be obtained only by the owner of the given domain name and is provided by the present 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 usually contains digits and special symbols, so as to obstruct unauthenticated persons from cracking it. Certain domain registrars even alter the codes of domain names registered through them after a given interval of time for greater safety.