{"department":[{"_id":"64"}],"main_file_link":[{"open_access":"1","url":"https://eprint.iacr.org/2013/646"}],"file_date_updated":"2018-03-15T10:35:04Z","citation":{"bibtex":"@article{Blömer_Liske_2013, title={Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles}, publisher={Universität Paderborn}, author={Blömer, Johannes and Liske, Gennadij}, year={2013} }","mla":"Blömer, Johannes, and Gennadij Liske. <i>Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles</i>. Universität Paderborn, 2013.","ieee":"J. Blömer and G. Liske, “Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles.” Universität Paderborn, 2013.","ama":"Blömer J, Liske G. Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles. 2013.","short":"J. Blömer, G. Liske, (2013).","apa":"Blömer, J., &#38; Liske, G. (2013). Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles. Universität Paderborn.","chicago":"Blömer, Johannes, and Gennadij Liske. “Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles.” Universität Paderborn, 2013."},"author":[{"last_name":"Blömer","first_name":"Johannes","full_name":"Blömer, Johannes","id":"23"},{"last_name":"Liske","first_name":"Gennadij","full_name":"Liske, Gennadij"}],"has_accepted_license":"1","date_updated":"2022-01-06T07:01:51Z","year":"2013","file":[{"creator":"florida","relation":"main_file","success":1,"date_created":"2018-03-15T10:35:04Z","file_id":"1292","content_type":"application/pdf","file_name":"538-AB-KEM_01.pdf","date_updated":"2018-03-15T10:35:04Z","file_size":389797,"access_level":"closed"}],"user_id":"25078","date_created":"2017-10-17T12:42:37Z","status":"public","project":[{"name":"SFB 901","_id":"1"},{"name":"SFB 901 - Subprojekt C1","_id":"13"},{"name":"SFB 901 - Project Area C","_id":"4"},{"name":"Securing the Financial Cloud","_id":"43"}],"type":"preprint","publisher":"Universität Paderborn","ddc":["040"],"abstract":[{"lang":"eng","text":"We present a new technique to realize attribute-based encryption (ABE) schemes secure in the standard model against chosen-ciphertext attacks (CCA-secure). Our approach is to extend certain concrete chosen-plaintext secure (CPA-secure) ABE schemes to achieve more efficient constructions than the known generic constructions of CCA-secure ABE schemes. We restrict ourselves to the construction of attribute-based key encapsulation mechanisms (KEMs) and present two concrete CCA-secure schemes: a key-policy attribute-based KEM that is based on Goyal's key-policy ABE and a ciphertext-policy attribute-based KEM that is based on Waters' ciphertext-policy ABE. To achieve our goals, we use an appropriate hash function and need to extend the public parameters and the ciphertexts of the underlying CPA-secure encryption schemes only by a single group element. Moreover, we use the same hardness assumptions as the underlying CPA-secure encryption schemes."}],"_id":"538","oa":"1","title":"Direct Chosen-Ciphertext Secure Attribute-Based Key Encapsulations without Random Oracles"}