Essam Ghadafi's Outputs (27)

Decentralized traceable attribute-based signatures (2014)
Presentation / Conference Contribution

We provide a formal security model for traceable attribute-based signatures. Our focus is on the more practical case where attribute management is distributed among different authorities rather than relying on a single central authority. By specializ... Read More about Decentralized traceable attribute-based signatures.

Formalizing group blind signatures and practical constructions without random oracles (2013)
Presentation / Conference Contribution

Group blind signatures combine anonymity properties of both group signatures and blind signatures and offer privacy for both the message to be signed and the signer. The primitive has been introduced with only informal definitions for its required se... Read More about Formalizing group blind signatures and practical constructions without random oracles.

Efficient signatures of knowledge and DAA in the standard model (2013)
Presentation / Conference Contribution

Direct Anonymous Attestation (DAA) is one of the most complex cryptographic protocols deployed in practice. It allows an embedded secure processor known as a Trusted Platform Module (TPM) to attest to the configuration of its host computer without vi... Read More about Efficient signatures of knowledge and DAA in the standard model.

Anonymous attestation with user-controlled linkability (2013)
Journal Article

This paper is motivated by the observation that existing security models for direct anonymous attestation (DAA) have problems to the extent that insecure protocols may be deemed secure when analysed under these models. This is particularly disturbing... Read More about Anonymous attestation with user-controlled linkability.

Efficient two-move blind signatures in the common reference string model (2012)
Presentation / Conference Contribution

Blind signatures provide a mechanism for achieving privacy and anonymity whereby a user gets the signer to sign a message of his choice without the signer learning the message, or being able to link a signature to the protocol run via which it was ob... Read More about Efficient two-move blind signatures in the common reference string model.

Groth-Sahai proofs revisited (2010)
Presentation / Conference Contribution

Since their introduction in 2008, the non-interactive zero-knowledge (NIZK) and non-interactive witness indistinguishable (NIWI) proofs designed by Groth and Sahai have been used in numerous applications. In this paper, we offer two contributions to... Read More about Groth-Sahai proofs revisited.

Practical zero-knowledge proofs for circuit evaluation (2009)
Presentation / Conference Contribution

Showing that a circuit is satisfiable without revealing information is a key problem in modern cryptography. The related (and more general) problem of showing that a circuit evaluates to a particular value if executed on the input contained in a publ... Read More about Practical zero-knowledge proofs for circuit evaluation.