Crypto-Multimedia, by Benlcouiri Younes and Azizi Abdelmalek and Moulay Chrif Ismaili
This paper is structured on securing of storage, transmission and the traceability of digital images. It consists in the design of the cryptographic algorithms appropriate to the case of fixed and moving images.
In this sense, we have introduced two approaches that is different in the synthesis of confusion and diffusion on using the principles of substitu-tion and/or transposition to secure JPEG and MPEG format.
Cryptanalysis and Security Enhancement of Two Advanced Authentication Protocols, by Sai Raghu Talluri and Swapnoneel Roy
In this work we consider two protocols for performing cryptanalysis and security enhancement. The first one by Jiang et al., is a password-based authentication scheme which does not use smart cards. We note that this scheme is an improvement over Chen et al.\'s scheme shown vulnerable to the off-line dictionary attack by Jiang et al. We perform a cryptanalysis on Jiang at al.\'s improved protocol and observe that it is prone to the clogging attack, a kind of denial of service (DoS) attack. We then suggest an improvement on the protocol to prevent the clogging attack.
The other protocol we consider for analysis is by Wang et al. This is a smart card based authentication protocol. We again perform the clogging (DoS) attack on this protocol via replay. We observe that all smart card based authentication protocols which precede the one by Wang et al., and require the server to compute the computationally
intensive modular exponentiation are prone to the clogging attack. We suggest (another) improvement on the protocol to prevent the clogging attack, which also applies to the protocol by Jiang et. al.
Ph.D. students, TELECOM-ParisTech
TELECOM-ParisTech crypto group seeks 4 PhD students
TELECOM-ParisTech crypto group develops prototype solutions to fight against cyber and physical penetration of embedded devices.
Our contributions in this field of research are:
We seek four PhD candidates on those subjects:
- \\\"Calculer dans les codes comme contremesure aux attaques physiques\\\", https://edite-de-paris.fr/spip/spip.php?page=phdproposal&id=10213751
- \\\"Native Protection of Processors against Cyber-Attacks\\\", https://edite-de-paris.fr/spip/spip.php?page=phdproposal&id=10253861
- \\\"Insertion automatique de contre-mesures dans des circuits de sécurité\\\", https://edite-de-paris.fr/spip/spip.php?page=phdproposal&id=10213779
- \\\"Attaques FIRE : Rétroconception de cryptographie secrète\\\", https://edite-de-paris.fr/spip/spip.php?page=phdproposal&id=10166999
Working language is French or English.
Positions are open until Aug 2014.
A Second Look at Fischlin\'s Transformation, by Özgür Dagdelen and Daniele Venturi
Fischlin\'s transformation is an alternative to the standard Fiat-Shamir transform to turn a certain class of public key identification schemes into digital signatures (in the random oracle model).
We show that signatures obtained via Fischlin\'s transformation are existentially unforgeable even in case the adversary is allowed to get arbitrary (yet bounded) information on the entire state of the signer (including the signing key and the random coins used to generate signatures). A similar fact was already known for the Fiat-Shamir transform, however, Fischlin\'s transformation allows for a significantly higher leakage parameter than Fiat-Shamir.
Moreover, in contrast to signatures obtained via Fiat-Shamir, signatures obtained via Fischlin enjoy a tight reduction to the underlying hard problem. We use this observation to show (via simulations) that Fischlin\'s transformation, usually considered less efficient, outperforms the Fiat-Shamir transform in verification time for a reasonable choice of parameters. In terms of signing Fiat-Shamir is faster for equal signature sizes. Nonetheless, our experiments show that the signing time of Fischlin\'s transformation becomes, e.g., 22% of the one via Fiat-Shamir if one allows the signature size to be doubled.
Practical Receipt-Free Sealed-Bid Auction in the Coercive Environment, by Jaydeep Howlader, Sanjit Kumar Roy, Ashis Kumar Mal
Sealed-Bid auction is an efficient and rational method to
establish the price in open market. However sealed-bid auctions are sub-
ject to bid-rigging attack. Receipt-free mechanisms were proposed to
prevent bid-rigging. The prior receipt-free mechanisms are based on two
assumptions; firstly, existence of untappable channel between bidders
and auction authorities. Secondly, mechanisms assume the authorities
to be honest (not colluding). Moreover the bandwidth required to com-
municate the receipt-free bids is huge. This paper presents a sealed-bid
auction mechanism to resist bid-rigging. The proposed method does not
assume untappable channel nor consider the authorities to be necessarily
honest. The proposed mechanism also manages the bandwidth efficiently,
and improves the performance of the system.