講演抄録/キーワード |
講演名 |
2012-12-12 16:30
[招待講演]On the Impossibility of Constructing Efficient Key Encapsulation and Programmable Hash Functions in Prime Order Groups Goichiro Hanaoka・○Takahiro Matsuda(AIST)・Jacob Schuldt(RHUL) ISEC2012-79 |
抄録 |
(和) |
2012年8月19日から23日に米国・サンタバーバラで開催された暗号研究分野の国際会議 CRYPTO 2012において、著者らが発表した同タイトルの講演内容を紹介・解説する。 |
(英) |
In this invited talk, we introduce the lecture with the same title presented at the 32nd International Cryptology Conference (CRYPTO 2012) held from August 19th to 23rd, 2012, at Santa Barbara, USA.\\ \\
[Abstract from the original paper (with a slight modification):] In this work, we focus on the problem of minimizing ciphertext overhead, and discuss the (im)possibility of constructing key encapsulation mechanisms (KEMs) with low ciphertext overhead. More specifically, we rule out the existence of algebraic black-box reductions from the (one-way, bounded) CCA security of a natural class of KEMs to any non-interactive problem. The class of KEMs captures the structure of the currently most efficient KEMs defined in standard prime order groups, but restricts an encapsulation to consist of a single group element and a string. This result suggests that we cannot rely on existing techniques to construct a CCA secure KEM in standard prime order groups with a ciphertext overhead lower than two group elements. Furthermore, we show how the properties of an (algebraic) programmable hash function can be exploited to construct a simple, efficient and (one-way, bounded) CCA secure KEM based on the hardness of the computational Diffie-Hellman problem with the ciphertext overhead of just a single group element. Since this KEM construction is covered by the above mentioned impossibility result, this enables us to derive a lower bound on the hash key size of an algebraic programmable hash function, and rule out the existence of algebraic $({\sf poly},n)$-programmable hash functions in prime order groups for any integer $n$. The latter result answers an open question posed by Hofheinz and Kiltz (CRYPTO'08, J. Cryptology'12) in the case of algebraic programmable hash functions in prime order groups. |
キーワード |
(和) |
鍵カプセル化メカニズム / 選択暗号文攻撃に対する安全性 / プログラム可能ハッシュ関数 / 代数的ブラックボックス帰着 / / / / |
(英) |
key encapsulation / chosen ciphertext security / programmable hash / algebraic black-box reductions / / / / |
文献情報 |
信学技報, vol. 112, no. 342, ISEC2012-79, pp. 43-43, 2012年12月. |
資料番号 |
ISEC2012-79 |
発行日 |
2012-12-05 (ISEC) |
ISSN |
Print edition: ISSN 0913-5685 Online edition: ISSN 2432-6380 |
著作権に ついて |
技術研究報告に掲載された論文の著作権は電子情報通信学会に帰属します.(許諾番号:10GA0019/12GB0052/13GB0056/17GB0034/18GB0034) |
PDFダウンロード |
ISEC2012-79 |
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