Corrections

This commit is contained in:
2018-06-16 19:05:57 +02:00
parent 5df7a6aa93
commit 00ad910d51
2 changed files with 48 additions and 43 deletions

View File

@@ -2,18 +2,18 @@
\section %hack for vim-latexsuite
\end{comment}
In this thesis, we presented new cryptographic schemes that relies on lattice or pairing assumptions.
In this thesis, we presented new cryptographic schemes that rely on lattice or pairing assumptions.
These contributions focus on the design and analysis of new cryptographic schemes that target privacy-preserving applications.
In pairing-related cryptography, we propose a practical dynamic group signature scheme, for which security is well understood.
It relies on broadly used assumptions with simple statements that exists for more than ten years.
This work is also supported by an implementation in C.
In pairing-based cryptography, we propose a practical dynamic group signature scheme, for which security is well understood.
It relies on broadly used assumptions with simple statements which exist for more than ten years.
This work is also supported by an implementation in \texttt{C}.
Our work in the lattice work give rise of three fundamental schemes that were missing in the landscape of lattice-based privacy-preserving primitives.
Our work in the lattice setting gives rise to three fundamental schemes that were missing in the landscape of lattice-based privacy-preserving cryptography.
Even if these schemes suffer from some efficiency issues due to their novelty, we do believe that it's one step toward a quantum-secure privacy-friendly world.
In the way of doing it, improvements have been made in the state of zero-knowledge proofs in the lattice setting as well as providing building blocks that, we believe, are of independent interest.
As of our signature with efficient protocols, which have been used to provide a lattice-based e-cash system~\cite{LLNW17}.
In the way of doing it, improvements have been made in the state of the art of zero-knowledge proofs in the lattice setting as well as providing building blocks that, we believe, are of independent interest.
As of our signature with efficient protocols, it has already been used to design a lattice-based e-cash system~\cite{LLNW17}.
All these works are proven under strong security model within simple assumptions.
This made a breeding ground for new theoretical constructions, as well as going toward practicality.
@@ -21,16 +21,16 @@ This made a breeding ground for new theoretical constructions, as well as going
\section*{Open Problems}
The path of providing new cryptographic primitives and proving them is disseminated with pitfalls.
The most obvious questions that stem from this work are about how to tackle the compromises we made in the design of those primitives.
The most obvious questions that stem from this work are about how to tackle the trade-offs we made in the design of those primitives.
\begin{question}
Is it possible to build an adaptive oblivious transfer with access control secure under $\LWE$ with polynomially large modulus?
\end{question}
In other words, is it possible to avoid the use of smudging to guarantee message-privacy in the oblivious transfer scheme of~\cref{ch:ot-lwe}.
As is, this problem arises from the use of Regev's encryption scheme, which does not guarantee this message privacy.
As is, this issue arises from the use of Regev's encryption scheme, which does not guarantee this message privacy.
However, finer analysis on GSW ciphertexts~\cite{GSW13} seems promising to achieve this at reasonable cost~\cite{BDPMW16}.
Then, the main difficulty is to have compatible zero-knowledge proof with the access control and the encryption layers.
Then, the main difficulty is to have zero-knowledge proofs compatible with the access control and the encryption layers.
\subsection*{Zero-Knowledge Proofs}
@@ -39,7 +39,7 @@ Then, the main difficulty is to have compatible zero-knowledge proof with the ac
\end{question}
Extending the work of Groth, Ostrovsky and Sahai~\cite{GOS06} in the lattice setting would be a great improvement for lattice-based privacy-preserving cryptography.
Recent line of work goes toward this direction~\cite{RSS18}, but relies on non-existing primitive yet ($\NIZK$ proofs for a variant of the bounded decoding distance problem).
Recent line of work goes toward this direction~\cite{RSS18}, but relies on primitives that do not exist yet ($\NIZK$ proofs for a variant of the bounded decoding distance problem).
The Stern-like proof system we work on in during this thesis, despite being flexible enough to prove a large variety of statements, suffers from the stiffness of being combinatorial.
The choice of permutations used to ensure zero-knowledgeness (and so witness-indistinguishability) is quite strict, and force the challenge space to be ternary.
@@ -73,8 +73,8 @@ Actually, even the question of having a trapdoorless \textsf{IND-CCA2} public ke
Can we achieve better security proofs for cryptographic schemes?
\end{question}
Our work during this thesis also focus on the proof of cryptographic schemes.
Our work during this thesis also focuses on the security proofs of cryptographic schemes.
As explained in~\cref{ch:proofs}, it is important to rely on simple assumptions to prove strong security notions.
Given the advances in cryptographic proofs~\cite{Hof16,KMP16,Hof17}, it is now possible to attain stronger security notions than what was claim before~\cite{DSYC18}.
Another line of work looks at the quality of the reduction, aiming for \textit{tight security}~\cite{GHKW16,AHN+17}.
This improves the understanding of the link between the cryptographic scheme and the security assumption, leading to more reliable schemes.
Given recent advances in cryptographic proofs~\cite{Hof16,KMP16,Hof17}, it is now possible to attain stronger security notions than what was claim before~\cite{DSYC18}.
Another line of work targets the quality of the reduction, aiming for \textit{tight security}~\cite{GHKW16,AHN+17}.
This improves the understanding of the links between cryptographic schemes and security assumptions, leading to more reliable constructions.