Ali Kaafarani - Academia.edu (original) (raw)
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Papers by Ali Kaafarani
IACR Cryptol. ePrint Arch., 2017
Direct Anonymous Attestation (DAA) is a complex cryptographic protocol that has been widely deplo... more Direct Anonymous Attestation (DAA) is a complex cryptographic protocol that has been widely deployed in practice, with more than 500 million machines in the market that are already equipped with its hardware, the so-called Trusted Module Platform (TPM). While formalizing the right security model for such a complex protocol has triggered a dense line of research, all the proposed DAA schemes so far are based on numbertheoretic problems that are known to be vulnerable to quantum computer attacks. In this paper, we propose the first lattice-based DAA scheme that is secure w.r.t. the most up-to-date security model proposed by Camenisch et al. More precisely, our latticebased DAA scheme is secure in the Universally Composable (UC) security model. Furthermore, we give (amongst others) the first lattice-based DAA scheme providing user controlled linkability that is realized by means of a new lattice-based MAC/TAG construction which could be of independent interest.
Lecture Notes in Computer Science, 2014
In this paper, we introduce Attribute-Based Signatures with User-Controlled Linkability (ABS-UCL)... more In this paper, we introduce Attribute-Based Signatures with User-Controlled Linkability (ABS-UCL). Attribute-based signatures allow a signer who has enough credentials/attributes to anonymously sign a message w.r.t. some public policy revealing neither the attributes used nor his identity. User-controlled linkability is a new feature which allows a user to make some of his signatures directed at the same recipient linkable while still retaining anonymity. Such a feature is useful for many reallife applications. We give a general framework for constructing ABS-UCL and present an efficient instantiation of the construction that supports multiple attribute authorities.
IACR Cryptol. ePrint Arch., 2017
Direct Anonymous Attestation (DAA) is a complex cryptographic protocol that has been widely deplo... more Direct Anonymous Attestation (DAA) is a complex cryptographic protocol that has been widely deployed in practice, with more than 500 million machines in the market that are already equipped with its hardware, the so-called Trusted Module Platform (TPM). While formalizing the right security model for such a complex protocol has triggered a dense line of research, all the proposed DAA schemes so far are based on numbertheoretic problems that are known to be vulnerable to quantum computer attacks. In this paper, we propose the first lattice-based DAA scheme that is secure w.r.t. the most up-to-date security model proposed by Camenisch et al. More precisely, our latticebased DAA scheme is secure in the Universally Composable (UC) security model. Furthermore, we give (amongst others) the first lattice-based DAA scheme providing user controlled linkability that is realized by means of a new lattice-based MAC/TAG construction which could be of independent interest.
Lecture Notes in Computer Science, 2014
In this paper, we introduce Attribute-Based Signatures with User-Controlled Linkability (ABS-UCL)... more In this paper, we introduce Attribute-Based Signatures with User-Controlled Linkability (ABS-UCL). Attribute-based signatures allow a signer who has enough credentials/attributes to anonymously sign a message w.r.t. some public policy revealing neither the attributes used nor his identity. User-controlled linkability is a new feature which allows a user to make some of his signatures directed at the same recipient linkable while still retaining anonymity. Such a feature is useful for many reallife applications. We give a general framework for constructing ABS-UCL and present an efficient instantiation of the construction that supports multiple attribute authorities.