Presentation 2002/11/7
OAEP Reconsidered+
Yuichi KOMANO, Kazuo OHTA,
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Abstract(in English) In order to prove the security of OAEP and OAEP+, there are two methods, Game method and Event method. In the former method, we modify the adversary's (A's) view step by step, and reduce the success probability of reduction algorithm in each game. In the latter one, we modify A's view at once, divide an event in several events which reduce the success probability, and estimate them as a whole. OAEP has been proved its security by both Game method and Event method, and OAEP+ has been proved only by Game method. There is, moreover, no comparison between these methods. In this paper, we reconsider the security proofs for OAEP and OAEP+ by both methods, give tighter ones, and prove the security of OAEP+ by Event method. Consequently, we show that by constructing games or dividing events carefully, these methods give the same reduction efficiency, which is expected optimal for OAEP and OAEP+. We claim the reason of its optimum.
Keyword(in Japanese) (See Japanese page)
Keyword(in English) OAEP / OAEP+ / provably secure / reduction / adaptive chosen ciphertext attack
Paper # ISEC2002-74
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Committee ISEC
Conference Date 2002/11/7(1days)
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Registration To Information Security (ISEC)
Language JPN
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) OAEP Reconsidered+
Sub Title (in English)
Keyword(1) OAEP
Keyword(2) OAEP+
Keyword(3) provably secure
Keyword(4) reduction
Keyword(5) adaptive chosen ciphertext attack
1st Author's Name Yuichi KOMANO
1st Author's Affiliation Waseda University()
2nd Author's Name Kazuo OHTA
2nd Author's Affiliation University of Electro-Communications
Date 2002/11/7
Paper # ISEC2002-74
Volume (vol) vol.102
Number (no) 436
Page pp.pp.-
#Pages 8
Date of Issue