International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Le Trieu Phong

Publications

Year
Venue
Title
2015
EPRINT
2015
EPRINT
2010
EPRINT
Efficiency-Improved Fully Simulatable Adaptive OT under the DDH Assumption
Kaoru Kurosawa Ryo Nojima Le Trieu Phong
At Asiacrypt 2009, Kurosawa and Nojima showed a fully simulatable adaptive oblivious transfer (OT) protocol under the DDH assumption in the standard model. However, Green and Hohenberger pointed out that the communication cost of each transfer phase is O(n), where n is the number of the sender's messages. In this paper, we show that the cost can be reduced to O(1) by utilizing a verifiable shuffle protocol.
2008
EPRINT
Blind HIBE and its Applications to Identity-Based Blind Signature and Blind Decryption
Le Trieu Phong Wakaha Ogata
We explicitly describe and analyse \textit{blind} hierachical identity-based encryption (\textit{blind} HIBE) schemes, which are natural generalizations of blind IBE schemes \cite{gh07}. We then uses the blind HIBE schemes to construct: (1) An identity-based blind signature scheme secure in the standard model, under the computational Diffie-Hellman (CDH) assumption, and with much shorter signature size and lesser communication cost, compared to existing proposals. (2) A new mechanism supporting a user to buy digital information over the Internet without revealing what he/she has bought, while protecting the providers from cheating users.
2006
EPRINT
On a Variation of Kurosawa-Desmedt Encryption Scheme
Le Trieu Phong Wakaha Ogata
Kurosawa-Desmedt encryption scheme is a variation of Cramer-Shoup encryption schemes, which are the first practical schemes secure against adaptive chosen ciphertext attack in standard model. We introduce a variant of Kurosawa-Desmedt encryption scheme, which is not only secure against adaptive chosen ciphertext attack but also slightly more efficient than the original version.
2006
EPRINT
Some Practical Public-Key Encryption Schemes in both Standard Model and Random Oracle Model
Le Trieu Phong Ogata Wakaha
In this paper, we present some more results about the security of the Kurosawa-Desmedt encryption scheme and a variant of it. We prove that after a modification, those schemes are secure against adaptive chosen-ciphertext attack not only under the decisional Diffie-Hellman assumption in standard model as before but also under the computational Diffie-Hellman assumption in the random oracle model. These results ensure that both the Kurosawa-Desmedt scheme and the variant have similar security merits as the Cramer-Shoup encryption scheme, which is proposed as a standard.