Publications de Atefeh Mashatan

Revisiting Iterated Attacks in the Context of Decorrelation Theory

Serge Vaudenay, Atefeh Mashatan, Asli Bay

Iterated attacks are comprised of iterating adversaries who can make d plaintext queries, in each iteration to compute a bit, and are trying to distinguish between a random cipher C and the perfect cipher C* based on all bits. Vaudenay showed that a 2d-dec ...

2014

Resistance against Adaptive Plaintext-Ciphertext Iterated Distinguishers

Serge Vaudenay, Atefeh Mashatan, Asli Bay

Decorrelation Theory deals with general adversaries who are mounting iterated attacks, i.e., attacks in which an adversary is allowed to make d queries in each iteration with the aim of distinguishing a random cipher C from the ideal random cipher C^*. A b ...

2012

Forgery-Resilience for Digital Signature Schemes

Khaled Ouafi, Atefeh Mashatan

We introduce the notion of forgery-resilience for digital signature schemes, a new paradigm for digital signature schemes exhibiting desirable legislative properties. It evolves around the idea that, for any message, there can only be a unique valid signat ...

2012

Resistance Against Iterated Attacks by Decorrelation Revisited

Serge Vaudenay, Atefeh Mashatan, Asli Bay

Iterated attacks are comprised of iterating adversaries who can make

d

plaintext queries, in each iteration to compute a bit, and are trying to distinguish between a random cipher

C

and the ideal random cipher

C^*

based on all bits. In EUROCRYPT '99, ...

Springer2012

Efficient Fail-Stop Signatures from the Factoring Assumption

Khaled Ouafi, Atefeh Mashatan

In this paper, we revisit the construction of fail-stop signatures from the factoring assumption. These signatures were originally proposed to provide information-theoretic-based security against forgeries. In contrast to classical signature schemes, in wh ...

Springer2011

A Related-Key Attack against Multiple Encryption based on Fixed Points

Serge Vaudenay, Atefeh Mashatan, Asli Bay

In order to alleviate the burden of short keys, encrypting a multiple times has been proposed. In the multiple encryption mode, there may be encryptions under the same or different keys. There have been several attacks against this encryption mode. When tr ...

Springer2011

Practical unconditionally secure two-channel message authentication

Atefeh Mashatan

We investigate unconditional security for message authentication protocols that are designed using two-channel cryptography. (Two-channel cryptography employs a broadband, insecure wireless channel and an authenticated, narrow-band manual channel at the sa ...

2010

A Message Recognition Protocol Based on Standard Assumptions

Serge Vaudenay, Atefeh Mashatan

We look at the problem of designing Message Recognition Protocols (MRP) and note that all proposals available in the literature have relied on security proofs which hold in the random oracle model or are based on non-standard assumptions. Incorporating ran ...

Springer2010

Methods for efficient certificate revocation list compression

Serge Vaudenay, Rafik Chaabouni, Imad Aad, Valtteri Niemi, Atefeh Mashatan

A method for providing efficient management of certificate revocation may comprise storing a list of identifiers of digital certificates including a revocation list defining a list of revoked certificates in an accumulator, storing a witness value in assoc ...

2010