{"created":"2021-03-01T06:18:28.710693+00:00","id":1886,"links":{},"metadata":{"_buckets":{"deposit":"23ae13be-fc52-429a-8d8a-226b60d2e794"},"_deposit":{"id":"1886","owners":[],"pid":{"revision_id":0,"type":"depid","value":"1886"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00001886","sets":["34:105:262","9:233:234"]},"item_7_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"補助鍵を用いた鍵隔離公開鍵暗号方式"}]},"item_7_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2008-03","bibliographicIssueDateType":"Issued"},"bibliographic_titles":[{}]}]},"item_7_date_granted_25":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2008-03-24"}]},"item_7_degree_name_20":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"修士(情報理工学)"}]},"item_7_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"To deal with the problem of secret key exposure, Dodis, Katz, Xu and Yung proposed a key-insulated public key encryption (KIE), which uses the secure helper key to update the secret key more often and helps to minimize the damage overall. We take this idea further in improving the helper key security by introducing an auxiliary helper key besides of the main helper key. The auxiliary helper key is used less than the main helper key and can help the system to reduce the damage even in case of helper key exposure. This thesis give two different schemes of KIE with auxiliary helper key. There are trade-offs between public key length and ciphertext size, as well as between encryption algorithms and decryption algorithms in these two schemes. With these trade-offs, it is flexible to choose an efficient one to implement in reality. We also show concrete constructions with chosen-ciphertext security. The formal security proofs for all schemes are given in this thesis, based on the CBDH assumption in the random oracle model.","subitem_description_type":"Abstract"}]},"item_7_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"5726","nameIdentifierScheme":"WEKO"}],"names":[{"name":"ファン, ティランアン"}]}]},"item_7_select_21":{"attribute_name":"学位","attribute_value_mlt":[{"subitem_select_item":"master"}]},"item_7_subject_13":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"548","subitem_subject_scheme":"NDC"}]},"item_7_text_24":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_value":"情報理工学系研究科電子情報学専攻"}]},"item_7_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"大学院情報理工学系研究科電子情報学専攻"},{"subitem_text_value":"Graduate School of Information Science and Technology Department of Information and Communication Engineering The University of Tokyo"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Phan, Thi Lan Anh"}],"nameIdentifiers":[{"nameIdentifier":"5725","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-05-31"}],"displaytype":"detail","filename":"48066438.pdf","filesize":[{"value":"338.5 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"48066438.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/1886/files/48066438.pdf"},"version_id":"afa3e05f-2a56-4e32-be94-5217f0dc02c1"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"Key Insulated Public Key Encryption","subitem_subject_scheme":"Other"},{"subitem_subject":"Auxiliary Helper Key","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Using Auxiliary Helper Key in Key Insulated Public Key Encryption","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Using Auxiliary Helper Key in Key Insulated Public Key Encryption"}]},"item_type_id":"7","owner":"1","path":["234","262"],"pubdate":{"attribute_name":"公開日","attribute_value":"2011-08-08"},"publish_date":"2011-08-08","publish_status":"0","recid":"1886","relation_version_is_last":true,"title":["Using Auxiliary Helper Key in Key Insulated Public Key Encryption"],"weko_creator_id":"1","weko_shared_id":null},"updated":"2022-12-19T03:43:24.103579+00:00"}