arXiv subjects

Jorge Martins

Publications and source records attributed to Jorge Martins.

3 recordsLinked to original sources

arXiv2026

Detecting Vulnerabilities in Encrypted Software Code while Ensuring Code Privacy

Software vulnerabilities continue to be the primary cause of cyberattacks. It is crucial to identify vulnerabilities in applications' source code before attackers gain access to them and exploit any vulnerability they may contain. Developers have used static analysis tools (SATs) to find vulnerabilities in unprotected application code, and software testing companies have started offering software code analysis as a service to assist developers in these findings. Such services require access to unprotected code, which raises concerns about its privacy and intellectual property theft. Attackers can also perform this analysis using similar tools, if they gain access to the code. It is, therefore, beneficial to have a system that can maintain code privacy by protecting it with cryptographic techniques, while still allowing authorised people to detect vulnerabilities in the encrypted code. This paper presents such a solution, a novel approach to Software Quality and Privacy that allows source code to be analysed in a protected manner, preserving its privacy. The proposed solution combines Static Analysis with Searchable Symmetric Encryption (SSE) for confidential vulnerability detection, enabling data and dependency tracking for data flow analysis over encrypted source code. The solution represents the code's data and control flows as an Encrypted Inverted Index, in a connected way that enables SSE's queries for vulnerability discovery. The solution was implemented as the CoCoA tool and evaluated with synthetic and real PHP web applications. Results show that CoCoA has similar precision as (non-confidential) SATs - 93% - with real applications, requiring only 209 ms to process 4k LoC - a modest overhead of 42.7% compared to a non-confidential baseline. This paper also defines a new research field - Confidential Code Analysis -, from which other types of code analysis tasks can be derived.

cs.SE↗

arXiv2026

Detection of C3 in Titan with VLT-ESPRESSO

Titan is regarded as a natural laboratory in the Solar System for studying atmospheric photochemistry and the abiotic production of organic molecules on cold small exoplanets. Since the end of the Cassini-Huygens mission, telescope observations have enabled new detections of increasingly complex carbon-based molecules at infrared and sub-millimetre wavelengths, while the optical regime has been largely overlooked. Following a recent tentative detection of the 405 nm absorption band of C3 in Titan in archived optical VLT UVES spectra at resolving power R = 60000, this work reports an eight sigma detection of the C3 405 nm absorption band in Titan using dedicated ultra high resolution VLT ESPRESSO observations at R = 190000, the highest spectral resolution optical observations of Titan to date. The VLT ESPRESSO spectrum is compared to model spectra of Titan with varying C3 abundances. A chi squared analysis is used to assess the agreement between non solar spectral features and C3 absorption as the C3 abundance is varied, and a Bayesian Markov Chain Monte Carlo fit between model and observed spectra is performed. The chi squared analysis yields an eight sigma detection of C3, consistent with a C3 column density of approximately 1.5E13 cm-2, while the MCMC fit retrieves a C3 column density of 1.47E13 cm-2 at five sigma. These values are consistent with the order of magnitude predicted by photochemical models, which reach parts per million levels in the Titan mesosphere. This work demonstrates the usefulness of instruments and techniques originally developed for exoplanet research when applied to Solar System targets.

astro-ph.EP↗

arXiv2019

The impact of atmospheric dispersion in the performance of high-resolution spectrographs

Differential atmospheric dispersion is a wavelength-dependent effect introduced by the atmosphere. It is one of the instrumental errors that can affect the position of the target as perceived on the sky and its flux distribution. This effect will affect the results of astronomical observations if not corrected by an atmospheric dispersion corrector (ADC). In high-resolution spectrographs, in order to reach a radial velocity (RV) precision of 10 cm/s, an ADC is expected to return residuals at only a few tens of milli-arcseconds (mas). In fact, current state-of-the-art spectrographs conservatively require this level of residuals, although no work has been done to quantify the impact of atmospheric dispersion. In this work we test the effect of atmospheric dispersion on astronomical observations in general, and in particular on RV precision degradation and flux losses. Our scientific objective was to quantify the amount of residuals needed to fulfill the requirements set on an ADC during the design phase. We found that up to a dispersion of 100 mas, the effect on the RV is negligible. However, on the flux losses, such a dispersion can create a loss of ~2% at 380 nm, a significant value when efficiency is critical. The requirements set on ADC residuals should take into consideration the atmospheric conditions where the ADC will function, and also all the aspects related with not only the RV precision requirements but also the guiding camera used, the tolerances on the flux loss, and the different melt data of the chosen glasses.

astro-ph.IM↗