One of the most common domain validation techniques involves sending an email containing an authentication token or link to an email address that is likely to be administratively responsible for the domain. This could be the technical contact email address listed in the domain's WHOIS entry, or an administrative email like , , , or Postmaster (computing) the domain. Some Certificate Authorities may accept confirmation using , , or in the domain. The theory behind domain validation is that only the legitimate owner of a domain would be able to read emails sent to these administrative addresses.