👋 Hi I’m Valentin. Curiosity backed by rapid learning ability drives my career. I thrive on mastering new domains and technologies quickly:
My approach focuses on building clear mental models that cut through complexity - getting 95% of results with 20% of the effort through strategic learning and implementation.
“The most important trick to be happy is to realize that happiness is a choice that you make." — Naval Ravikant
Master in Computer Science, 2016
Télécom ParisTech
Preparatory School in Physics and Chemestry, 2013
Lycée Lakanal
What if we could stop wasting most of our development time re-developing the same thing again and again?
Verifiable credentials (VCs) are the translation of physical credentials like a driving license or a degree in the digital world. In practice, it means we are just signed JSON. Let’s see what an ‘hello world’ signed would look like.
Look inside: What’s the promise of the blockchain you believe in? That it will change the world? Or that it will make you rich?
Ce message est sans importance… (mais essentiel)
Co-founded a startup focused on automating long-form YouTube content creation (20-90 minutes) targeting niche markets. The goal was to enable content creators to efficiently produce high-quality videos and monetize through ad revenue.
Violet is a Web3 company specializing in digital identity and KYC solutions. As a software engineer, I focused on wallet integration and frontend development.
Qonto is a European neobank for professionals. To improve a higher quality of service for its clients, in 2018 it developed its own “Core Banking System”, meaning that it maintains itself all its clients' accounts and process all their transactions. (Beforehand it was relying on an external partner to do so.) At Qonto, I was part of the Ledger team, which maintains the “source of truth” for all accounts and their transactions. These micro-services were implemented using a Go plus PostgreSQL stack. Moreover, I did multiple interventions to improve and maintain Qonto’s billing system which is implemented using Ruby on Rails.
Qonto uses an advanced micro-service architecture with over 80 services (and counting!) being continuously deployed relying on Gitlab, Kubernetes and Argo CD.
Led development of an IT infrastructure monitoring platform with ML capabilities for incident prediction:
Led multiple high-impact research projects in software security:
Entropic is an information-theoretic power schedule implemented based on LibFuzzer. It boosts performance by changing weights assigned to the seeds in the corpus. Seeds revealing more “information” are assigned a higher weight.
Entropic received the ACM SIGSOFT Distinguished Paper Award! Furthermore, its code was made the default schedule in LibFuzzer @ LLVM (C++ code base), which powers Google’s OSSFuzz and Microsoft’s OneFuzz 🚀.
Grey-box fuzzing is an evolutionary process, which maintains and evolves a population of test cases with the help of a fitness function. Fitness functions used by current grey-box fuzzers are not informative in that they cannot distinguish different program executions as long as those executions achieve the same coverage. The problem is that current fitness functions only consider a union of data, but not their combination. As such, fuzzers often get stuck in a local optimum during their search. In this paper, we introduce Ankou, the first grey-box fuzzer that recognizes different combinations of execution information, and present several scalability challenges encountered while designing and implementing Ankou. Our experimental results show that Ankou is 1.94× and 8.0× more effective in finding bugs than AFL and Angora, respectively.
This paper surveys both the academic papers and the open-sourced tools in the field of fuzzing. We present a unified, general-purpose model to better understand the design and trade-offs of fuzzers.
Monolithic kernel is one of the prevalent configurations out of various kernel design models. While monolithic kernel excels in performance and management, they are unequipped forruntime system update; and this brings the need for kernel extension. Although kernel extensions are a convenient measure for system management, it is well established that they make the system prone to rootkit attacks and kernel exploitation as they share the single memory space with the rest of the kernel. To address this problem, various forms of isolation (e.g., making into a process), are so far proposed, yet their performance overhead is often too high or incompatible for a general purpose kernel. In this paper, we propose Domain Isolated Kernel (DIKernel), a new kernel architecture which securely isolates the untrustedkernel extensions with minimal performance overhead. DIKernel leverages hardware-based memory domain feature in ARM architecture; and prevents system manipulation attacks originated from kernel extensions, such as rootkits and exploits caused by buggy kernel extensions. We implemented DIKernel on top of Linux 4.13 kernel with 1500 LOC. Performance evaluation indicates that DIKernel imposes negligible overhead which is observed by cycle level microbenchmark.