Context: Homomorphic encryption techniques will play in the coming years a crucial role in securing cloud computing. These systems allow to delegate calculations or treatment to entities that will not be able to have a direct access to data. This is an essential primitive to ensure the confidentiality of data in applications such as Cloud Storage and Cloud Computing as customers deport some of their computing resources in the cloud by delegating the task to the remote service running on their procedure names on their private data.

It may be noted that despite the emergence of a large number of commercial services of this type, there exists to date no solution where users can completely trust the services that guarantee the confidentiality of their data as well as the communication between a user and the service.However, the new generation of homomorphic encryption schemes proposed in the literature since 2009 and is about to make a profound change of paradigm in cloud computing since these systems will allow to delegate treatments combining additions and multiplications directly on encrypted data, so without revealing the scope and results. They will play a crucial role in the safety of these services, ensuring confidentiality not only on data stored but also during data processing, even if the service is malicious or compromised by an intrusion.

Objectives: The aim of the thesis is to develop the first hardware cryptoprocessor dedicated to homomorphic cryptography. This is an important issue in order to enable the deployment of such systems.In publications [Fau 2013] and [Aguilar 2013] we showed that it was possible to achieve processing of information based on homomorphic encryption systems but the execution time in software is too penalizing.The objective of this thesis is to develop an architecture of cryptoprocessor dedicated to homomorphic encryption based on arithmetic operators efficiently handling very large numbers.For this purpose, this thesis is co-directed by Caroline FONTAINE expert in cryptography, Arnaud TISSERAND expert in arithmetic for cryptography and Guy GOGNIAT expert in digital architecture.
[Aguilar 2013] Carlos Aguilar Melchor, Simon Fau, Caroline Fontaine, Guy Gogniat, Renaud Sirdey: Recent Advances in Homomorphic Encryption: A Possible Future for Signal Processing in the Encrypted Domain. IEEE Signal Process. Mag. 30(2): 108-117 (2013) [Fau 2013] Simon Fau, Renaud Sirdey, Caroline Fontaine, Carlos Aguilar Melchor, Guy Gogniat: Towards Practical Program Execution over Fully Homomorphic Encryption Schemes. 3PGCIC 2013: 284-290