About me

photo

PhD Student in Cryptography

  • Paris, France
  • tancrede (dot) lepoint (at) cryptoexperts.com
  • +33 (0) 686-599-404

I am a PhD Student at École Normale Supérieure of Paris, France with David Pointcheval as advisor working on lattice-based cryptography and fully homomorphic encryption. My research topics also relate to the fine tuning of concrete scheme parameters to yield both efficient and practically secure implementations.

I am also a cryptography engineer at CryptoExperts in Paris, France to pursue my PhD in an industrial environment with Pascal Paillier as advisor.

research

Conference Publications

  1. New Lattice Signatures and Bimodal Gaussians
    L. Ducas, A. Durmus, T. Lepoint and V. Lyubashevsky
    To appear at CRYPTO 2013
  2. New Practical Multilinear Maps over the Integers
    J.-S. Coron, T. Lepoint and M. Tibouchi
    To appear at CRYPTO 2013 [ Eprint] [PoC implementation]
  3. Batch Fully Homomorphic Encryption over the Integers
    J. H. Cheon, J.-S. Coron, J. Kim, M. S. Lee, T. Lepoint, M. Tibouchi and A. Yun
    To appear at EUROCRYPT 2013 [ Eprint] (merged with this work)
  4. On the Minimal Number of Bootstrappings in Homomorphic Circuits
    T. Lepoint and P. Paillier
    WAHC 2013 [ Pdf]
  5. Partial key exposure on RSA with private exponents larger than N
    M. Joye and T. Lepoint
    ISPEC 2012 [ Pdf]
  6. Traitor tracing schemes for protected software implementations
    M. Joye and T. Lepoint
    ACM DRM 2011 [ Pdf]

Manuscripts


Theses

  1. Master 2's thesis: Towards Asymmetric White-Box Cryptography
    T. Lepoint
    Final report for Master S.C.C.I. (Security, Cryptography and Information Coding) of Grenoble. Internship in Technicolor, Rennes, April-September 2011. Advisor: Marc Joye.
  2. [FR] T.E.R. de Master 1 : Géometrie des groupes
    T. Lepoint
    Travail d'étude et de recherche pour le master 1 de mathématiques de Grenoble, 2010. Responsable : Benoît Kloeckner. [ Pdf]

Misc.

  1. Internship: Black-Box Secret Sharing
    T. Lepoint
    Internship in Nanyang Technological University, Singapore, June-July 2010. Advisor: Frédérique Oggier. [ Pdf]
  2. [FR] Note de cours L3 : Théorie de la mesure et de l'intégration
    Transcription du cours enseigné à l'université Joseph Fourier de Grenoble par Thierry Gallay en 2008-2009. [ Pdf]

Latex Tips

One will find below several LaTeX tips which could be useful, and I did not see elsewhere on the Internet. I do not guarantee their simplicity, and every tip to improve them or to bypass them are still welcomed.

Bibliography (cited on page x)

After each item in the bibliography, one can wish to insert the pages where this item is cited in the main document. The parameters backref,pagebackref=true can be added to the package hyperref.

However, the final design is not really beautiful and clean (according to me, since the pages are just added between bracks). Here a small redefinition of \backrefalt to modify it in whatever you want:

% simple backref command redefinition (not sure if it is necessary)
\renewcommand*{\backref}[1]{}
% redefinition of the actually used \backrefalt
\renewcommand*{\backrefalt}[4]{%
\ifcase #1 %
% case: not cited
\or
% case: cited on exactly one page
\bfseries [page~#2]%
\else
% case: cited on multiple pages
\bfseries [pages~#2]
\fi}

Answers and Hyperref

In order to provide correction of exercises sheets to my students, I wanted to give them a pdf file with crossed links between exercices and solutions, i.e. you can go from an exercise to its solution, and from the solution to the exercise.

The last time I checked, the packages answers and hyperref did not provide this ability without modification.

One will find below a minimal example in which such an ability is provided, namely, when you click on the exercise number, you obtain the solution; and when you click on the solution number, you get back the exercise.

See the result Download the .tex

Gaussian Distribution on Lattice

Normal sampling

See the result Download the .tex