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IdentityBased Encryption from the Weil Pairing
, 2001
"... We propose a fully functional identitybased encryption scheme (IBE). The scheme has chosen ciphertext security in the random oracle model assuming an elliptic curve variant of the computational DiffieHellman problem. Our system is based on bilinear maps between groups. The Weil pairing on elliptic ..."
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We propose a fully functional identitybased encryption scheme (IBE). The scheme has chosen ciphertext security in the random oracle model assuming an elliptic curve variant of the computational DiffieHellman problem. Our system is based on bilinear maps between groups. The Weil pairing on elliptic curves is an example of such a map. We give precise definitions for secure identity based encryption schemes and give several applications for such systems.
Identitybased ring signcryption scheme, Tien Tzu Hsueh Pao/Acta Electronica Sinica 34 (2
, 2006
"... In this paper, we present a new concept called an identity based ring signcryption scheme (IDRSC). We argue that this is an important cryptographic primitive that must be used to protect privacy and authenticity of a collection of users who are connected through an adhoc network, such as Bluetooth. ..."
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In this paper, we present a new concept called an identity based ring signcryption scheme (IDRSC). We argue that this is an important cryptographic primitive that must be used to protect privacy and authenticity of a collection of users who are connected through an adhoc network, such as Bluetooth. We also present an efficient IDRSC scheme based on bilinear pairing.As a regular signcryption scheme, our scheme combines the functionality of signature and encryption schemes. However, the idea is to have an identity based system. In our scheme, a user can anonymously signcrypts a message on behalf of the group. We show that our scheme outperforms a traditional identity based scheme, that is obtained by a standard signthenencrypt mechanism, in terms of the length of the ciphertext. We also provide a formal proof of our scheme with the chosen ciphertext security under the Decisional Bilinear DiffieHellman assumption, which is believed to be intractable.
Kresilient identitybased encryption in the standard model
 In Topics in Cryptology CTRSA 2004
, 2004
"... Abstract. We present and analyze an adaptive chosen ciphertext secure (INDCCA) identitybased encryption scheme (IBE) based on the well studied Decisional DiffieHellman (DDH) assumption. The scheme is provably secure in the standard model assuming the adversary can corrupt up to a maximum of k use ..."
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Cited by 9 (0 self)
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Abstract. We present and analyze an adaptive chosen ciphertext secure (INDCCA) identitybased encryption scheme (IBE) based on the well studied Decisional DiffieHellman (DDH) assumption. The scheme is provably secure in the standard model assuming the adversary can corrupt up to a maximum of k users adaptively. This is contrary to the BonehFranklin scheme which holds in the randomoracle model. Key words: identitybased encryption, standard model 1
CryptoBook: An Architecture for Privacy Preserving Online Identities
"... Through crosssite authentication schemes such as OAuth and OpenID, users increasingly rely on popular social networking sites for their digital identities–but use of these identities brings privacy and tracking risks. We propose CryptoBook, an extension to existing digital identity infrastructur ..."
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Through crosssite authentication schemes such as OAuth and OpenID, users increasingly rely on popular social networking sites for their digital identities–but use of these identities brings privacy and tracking risks. We propose CryptoBook, an extension to existing digital identity infrastructures that offers privacypreserving, digital identities through the use of public key cryptography and ring signatures. CryptoBook builds a privacypreserving cryptographic layer atop existing social network identities, via thirdparty key servers that convert social network identities into public/private keypairs on demand. Using linkable ring signatures, these keypairs along with the public keys of other identities create unique pseudonyms untraceable back to the owner yet can resist anonymous abuse. Our proofofconcept implementation of CryptoBook creates public/private key pairs for Facebook users, and includes a private key pickup protocol based on Email. We present Black Box, a case study application that uses CryptoBook for accountable anonymous whistleblowing. Black Box allows users to sign files deniably using ring signatures, using a list of arbitrary Facebook users – who need not consent or even be aware of this use – as an explicit anonymity set.
Constructing Twisted Anomalous Elliptic Curves
"... Abstract—Huhnlein et al showed that for totally nonaximal imaginary quadratic orders, the discrete logarithm problem can be reduced to the discrete logarithm problem in some finite fields. In previous work we showed that for twisted anomalous elliptic curves, the logarithm problem can also be reduc ..."
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Abstract—Huhnlein et al showed that for totally nonaximal imaginary quadratic orders, the discrete logarithm problem can be reduced to the discrete logarithm problem in some finite fields. In previous work we showed that for twisted anomalous elliptic curves, the logarithm problem can also be reduced to the logarithm problem in some finite fields. In this work we present an algorithm to construct this class of elliptic curves. Index Terms—discrete logarithm problem, imaginary quadratic order, elliptic curve, anomalous curve I I.
Index Term — Discrete logarithm problem
"... Abstract — Huhnlein et al showed that for totally nonaximal imaginary quadratic orders, the discrete logarithm problem can be reduced to the discrete logarithm problem in some finite fields. In previous work we showed that for twisted anomalous elliptic curves, the logarithm problem can also be re ..."
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Abstract — Huhnlein et al showed that for totally nonaximal imaginary quadratic orders, the discrete logarithm problem can be reduced to the discrete logarithm problem in some finite fields. In previous work we showed that for twisted anomalous elliptic curves, the logarithm problem can also be reduced to the logarithm problem in some finite fields. In this work we present an algorithm to construct this class of elliptic curves.
Universidade Federal de Pernambuco
, 2009
"... Not everything that is counted counts, and not everything that counts can be counted. ..."
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Not everything that is counted counts, and not everything that counts can be counted.
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"... Abstract Recently, Tanaka proposed an identity based noninteractive key sharing scheme based on the intractability of integer factorization and discrete logarithm. The proposed identity based noninteractive key sharing scheme is similar to the wellknown MaurerYacobi public key distribution schem ..."
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Abstract Recently, Tanaka proposed an identity based noninteractive key sharing scheme based on the intractability of integer factorization and discrete logarithm. The proposed identity based noninteractive key sharing scheme is similar to the wellknown MaurerYacobi public key distribution scheme but the computational complexity for private key generation can be significantly reduced. It is also claimed that the proposed identity based noninteractive key sharing scheme is &quot;collusionattack free&quot;, i.e., secure against collusion attacks. In this paper, we analyze the security of the &quot;collusionattack free &quot; identity based noninteractive key sharing scheme. First, we show that, without colluding with other users, a single user can recover some of the secret information of the private key generator. Then we show that a small group of users can collude to recover all of the secret information held by the private key generator. Thus, the &quot;collusionattack free &quot; identity based noninteractive key sharing scheme can be completely compromised by collusion attacks. Key words: identity based cryptosystem, noninteractive key sharing, integer factorization, discrete logarithm, collusion attack,
PAPER Special Section on Cryptography and Information Security kResilient IdentityBased Encryption in the Standard Model
, 2006
"... SUMMARY We present and analyze an adaptive chosen ciphertext secure (INDCCA) identitybased encryption scheme (IBE) based on the well studied Decisional DiffieHellman (DDH) assumption. The scheme is provably secure in the standard model assuming the adversary can corrupt up to a maximum of k users ..."
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SUMMARY We present and analyze an adaptive chosen ciphertext secure (INDCCA) identitybased encryption scheme (IBE) based on the well studied Decisional DiffieHellman (DDH) assumption. The scheme is provably secure in the standard model assuming the adversary can corrupt up to a maximum of k users adaptively. This is contrary to the BonehFranklin scheme which holds in the randomoracle model. key words: identitybased encryption, standard model 1.