Moez Ben MBarka, Francine Krief, Olivier Ly, Entrusting Remote Software Executed in an Untrusted Computation Helper, [PDF] [BibTex]
Submitted to the First International Conference on Network and Service Security, 2009
Abstract: How to trust an application executed in a remote untrusted client? Indeed, in an untrusted environment, an attacker may tamper with the application code or the execution environment to alter the application behavior for its own purposes. This problem is traditionally addressed by checking the integrity of the application code at loading and during runtime. However, this line of protection is not sufficient when the client is used as a computation helper and is expected to return the result to a trusted server. An attacker may execute the application without altering its code but returns an invalid result. A software-based solution is a combination of remote application integrity and remote application authentication tech-niques. This paper presents a new approach to deal with remote software execution in an untrusted client used as a computation helper.
Key words: remote software authentication, remote software integrity, computation helper, software monitoring, software obfuscation.

Moez Ben MBarka, Secure computing outsourcing. (April 2008): [PDF]
Abstract: Computation outsourcing is used when an entity needs to execute a task but does not have the appropriate computation power to perform it. In this paper, we will survey the approach of delegation: instead of doing the computation locally, the entity outsources it to one or more external helpers which have the appropriate resources. Although this can safely be done for most everyday life tasks (like making coffee), it is a more complicated question when dealing with computations which involve security requirements. Indeed, the entity owner may wish that the computation input to be kept secret from the helper. Furthermore, the involved helpers may be dishonest or corrupted and thus the task owner have to check that the returned result is correct. We will first survey some research works related to secure computation outsourcing. Then we will show some outsourcing models and related issues.
Key words: secure outsourcing, cryptographic processors.

Moez Ben Mbarka, Cryptographic processors: applications and attacks survey. (Febrary 2008), [PDF]
Abstract: The combination of cryptographic tools and tamper-resistant mechanisms appeared first in military applications to secure communication links using tamper-resistant cipher machines. The spread of ATM networks brought the technology into the commercial mainstream. During the last years, the use of embedded cryptographic processors has spread from low-cost cryptoprocessors, such as smart cards used for holding< decryption keys, to more modern applications, such as electronic payement schemes, Digital Right Management and Trusted Computing Initiative (TCI). This survey, will summarize the main applications of the cryptographic processors and will insist on their use into PKI based systems. It will also address the main class of attacks which target the cryptographic processors.
Key words: Cryptoprocessors, HSM, PKI, RSA, security API.

Moez Ben Mbarka, Control access policies for distributed resources. (January 2007), [PDF] [BibTex]
Abstract: Policies are more and more used to manage access control for distributed network applications . This interest essentially stems from the dynamicity that provides this approach. Policy-based management regards the multiple resources composing the system as a single abstract resource. This leads to write high level policies which need to be refined before to be distributed to the concretes resources. As, these resources should work as a global system, internal coordination may be needed. This paper proposes a model and a refinement process able to automatically produce low level policies. It also discuss a conceptual coordination model and suggests implementation issues.
Key words: control access policies, ditributed computing.

Projet de fin d'études, ENSEIRB (2007): Les signatures numériques évoluées en XML (XMLDSIG et XAdES).

Master Recherche , Université Bordeaux 1 (2007): Les signatures numériques évoluées en XML (XMLDSIG et XAdES).