cB

Carlo Brunetta

Email: brunetta@chalmers.se

Room: EDIT - 5125

About Me

Hej! I’m Carlo and I’m a Cryptography PhD student.

I ❤ Music, Nature and the Universe and I love Math ❤

I’m TAing the Cryptography, Computer Security and Network Security courses at Chalmers.

“If a man’s wit be wandering, let him study the mathematics.” - Francis Bacon

Master Thesis

Do you want to do a master thesis in Cryptography? Just contact me or drop in my office!

I’m happy to talk and see if we can collaborate!

WIP on some specific proposal

Research Interests

Block Cipher

Wiki

Block ciphers are fundamental primitives to build security and they have to be as secure as possible.

The security that a BC (alone) has to achieve is directly connected on how a BC is defined in the mathematical terms.

A lot of insecurity and attack that can be found are connected more on bad practices and/or computational security that it is now not more secure.

The intrinsic algebraic security is based on algebraic properties that a BC has or not. They can define mathematical attacks that can broke a cipher or not: maybe the attack is the best known but it is, still, computable infeasible.

So… math, algebra, breaking things… yeah… ❤

Homomoprhic Encryption

Wiki

Homomorphic encryption is a cryptographic scheme theoretically defined in 1978 by RSA’s peoples and then get (almost) practical usable by Craig Gentry in 2009.

WHAT IS HOMOMORPHIC ENCRYPTION?

HE wants to achieve the idea of algebraic homomorphism: have the possibility to do operation on encrypted data.

The idea is brilliant: you encrypt information and then can compute things without never knowing what you are working with! This permits to build scheme where the computation is done by a third entity (yeah, let’s call it the cloud) BUT homomorphic schemes are usually not that practical IRL 😢.

Blockchain

Wiki

Blockchain is a database with really peculiar rules. IMHO, there is still not a good killing-application for it.

That’s why, I’m interested in researching it!

Publications

A Differentially Private Encryption Scheme

DOI Link
Open PDF

ISC 2017

Abstract: Encrypting data with a semantically secure cryptosystem guarantees that nothing is learned about the plaintext from the ciphertext. However, querying a database about individuals or requesting for summary statistics can leak information. Differential privacy (DP) offers a formal framework to bound the amount of information that an adversary can discover from a database with private data, when statistical findings of the stored data are communicated to an untrusted party. Although both encryption schemes and differential private mechanisms can provide important privacy guarantees, when employed in isolation they do not guarantee full privacy-preservation. This paper investigates how to efficiently combine DP and an encryption scheme to prevent leakage of information. More precisely, we introduce and instantiate differentially private encryption schemes that provide both DP and confidentiality.

Hidden sums and their application on block ciphers

Conf. Link
Open PDF

WCC 2017

Abstract: We report the recent results on hidden sums obtained in the unpublished preprints by Brunetta, Calderini, and Sala. These hidden sums could be used to exploit some particular trapdoors in block ciphers. Each hidden sum is related to an elementary abelian regular subgroup. Focusing on the subgroups of the affine general linear group, we are able to characterize the maps generating these groups. From the characterization we obtain a polynomial-time algorithm to represent the elements of a binary vector space with respect to the hidden sum. Such an algorithm can be used to exploit the trapdoor in a block cipher. Then we design an efficient algorithm to perform the necessary preprocessing on the components of a cipher for the exploitation of the trapdoor.

This paper is the conference version of my master thesis “On some Computational Aspects for Hidden Sums in Boolean Functions” that can be found in the Trento University Library (link) or in pdf.

A more complete journal version will be published soon.

Towards the Verification of Image Integrity in Online News

DOI Version
Open PDF

ICMEW 2015

Abstract: The widespread of social networking services allows users to share and quickly spread an enormous amount of digital contents. Currently, a low level of security and trustworthiness is applied to such information, whose reliability cannot be taken for granted due to the large availability of image editing software which allow any user to easily manipulate digital contents. This has a huge impact on the deception of users, whose opinion can be seriously influenced by altered media. In this work, we face the challenge of verifying online news by analyzing the images related to the particular news article. Our goal is to create an empirical system which helps in verifying the consistency of visually and semantically similar images used within different news articles on the same topic.