Details about the recent cyber attacks against security firm RSA suggest the assailants may have been taunting the industry giant and the United States. Most of the domains trace back to so-called dynamic DNS providers, usually free services that allow users to have Web sites hosted on servers that frequently change their Internet addresses. The last domain listed includes the abbreviation PRC which could be a clever feint, or it could be Chinese attackers rubbing our noses in it, as if to say, Yes, it was the Peoples Republic of China that attacked you: What are you going to do about it?””]
Source: https://krebsonsecurity.com/2011/03/domains-used-in-rsa-attack-taunted-u-s/