Mention the year in which Chinese University of Hong Kong published a paper on Ring signatures.
When was the research paper on Ring signatures by Chinese University of Hong Kong published?
SELECT DISTINCT ?answer WHERE { <https://dblp.org/rec/journals/iacr/WeiY06> <https://dblp.org/rdf/schema#authoredBy> ?x . ?x <https://dblp.org/rdf/schema#primaryAffiliation> 'Chinese University of Hong Kong' . <https://dblp.org/rec/journals/iacr/WeiY06> <https://dblp.org/rdf/schema#yearOfPublication> ?answer }
<https://dblp.org/rec/journals/iacr/WeiY06>