Which search engine patented the concept of “TrustRank”

[cbsalliance]

Which search engine patented the concept of “TrustRank” as a methodology to rank websites and webpages?

[Akshay_M]

Yahoo!
Similarly, Search engines have many different algorithms and ranking factors that they use when measuring the quality of webpages. Yahoo! patented the concept of “ TrustRank ” to rank websites and webpages.