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Chaitanya Rahalkar

Software Security Engineer

Block Inc. (f.k.a. Square Inc.)

Biography

I’m a Software Security Engineer at Block Inc. (formerly Square Inc.), where I focus on developing enterprise-scale cloud-native security pipelines and detection systems. With a Master’s degree in Cybersecurity from Georgia Institute of Technology, I specialize in application security, cloud security, and security engineering.

My expertise spans across AWS cloud services, security tooling, and system administration. I have extensive experience in security auditing, vulnerability assessments, and developing security solutions. Previously, I’ve worked at Meta (Facebook) and Praetorian, where I contributed to various security initiatives including fuzzing infrastructure, security audits, and threat modeling.

I’m passionate about building secure systems and contributing to the security community. My research work spans across various domains including privacy-preserving techniques in cryptocurrencies, content moderation in encrypted systems, and secure system design.

Interests

  • Cloud-Native Security
  • Application Security
  • Security Engineering
  • Reverse Engineering
  • System Programming
  • Threat Modeling

Education

  • Master of Science in Cybersecurity, 2022

    Georgia Institute of Technology

  • Bachelor of Engineering in Computer Engineering, 2020

    Savitribai Phule Pune University

Experience

 
 
 
 
 

Software Security Engineer

Block Inc. (f.k.a. Square Inc.)

May 2023 – Present Remote, US
  • Lead the development of enterprise-scale cloud-native security pipelines and detection systems, driving operational excellence through performance optimization and robust monitoring solutions.
  • Spearhead cross-functional collaboration with stakeholders to architect and implement innovative security solutions, while maintaining 24/7 platform support through rotational on-call responsibilities.
  • Champion continuous improvement through code reviews, process refinements, and architectural recommendations, resulting in enhanced system scalability and cost optimization.
 
 
 
 
 

Security Engineer III

Praetorian

Jan 2023 – May 2023 Remote, US
  • Conducted over 100 comprehensive security audits, compliance assessments, vulnerability assessments, and penetration tests for Praetorian’s diverse client base.
  • Spearheaded the creation and refinement of 50+ threat models, penetration test reports, and finding reports; effectively communicated complex security discoveries to stakeholders.
  • Assessed the security integrity of web applications, mobile applications, and television apps, identifying and rectifying over 200 flaws and vulnerabilities for clients including Nordstrom, Block, Affirm, Salesforce, Fox News, Amazon and more.
  • Provided valuable mentorship to 10+ junior engineers, fostering professional growth and contributing to team efficiency.
  • Worked on security and backend engineering modules in Chariot (vulnerability management platform) and Nosey Parker (source-code secrets scanning tool).
 
 
 
 
 

Security Engineering Intern

Meta (previously Facebook)

May 2022 – Aug 2022 1 Hacker Way, Menlo Park, CA
  • Designed and developed coverage-guided fuzzing harnesses using LLVM Libfuzzer for Meta’s Continuous Fuzzing platform, Lionhead. Identified and reported over 10 security vulnerabilities in Meta’s production code and tooling systems.
  • Conducted security audits and static code analysis within the WhatsApp Payment Engine, identifying and documenting 5+ CVE-worthy security issues with a focus on security and privacy.
  • Assisted in the development of an automated fuzzing harness generation system, enhancing the scope of coverage-guided fuzzing across 100,000+ API endpoints.
  • Conceptualized and designed a comprehensive fuzzing metrics system and visualization dashboard to provide insights on coverage and fuzzing performance.
 
 
 
 
 

Security Engineer

BosLeo LLC

Jul 2020 – Jul 2021 Pan Card Club Road, Pune, India
  • Worked on the development of Anti-Virus, Anti-Phishing, Software Sandboxing, Application Firewall components as a part of the company’s Endpoint Protection Platform (EPP).
  • Architected and implemented a cutting-edge network-based intrusion detection system (NIDS) fortified with an intrusion analytics and insights system. Orchestrated the simulation, detection, and analysis of 100+ network intrusion attacks.
  • Modelled a Software-Defined Perimeter prototype based on the Zero Trust Network architecture.

Recent & Upcoming Talks

Centralized or Decentralized? The Contact Tracing Dilemma

This is a summary of the “Centralized or Decentralized? The Contact Tracing Dilemma” research paper having the following …

The Million Dollar Dissident

A talk about the Zero-Day exploit used by the NSO group on Ahmed Mansoor, its backstory, exploit and network infrastructure.

Summarizing and Analyzing the Privacy-Preserving Techniques in Bitcoin and other Cryptocurrencies

Bitcoin and many other similar Cryptocurrencies have been in existence for over a decade, prominently focusing on decentralized, …

Designing a Secure Device-to-Device File Transfer Mechanism

Secure, reliable, and fast transfer of files across the Internet is a problem attempted to be solved through many application-layer …

Hidden Secrets of Python

Python has a large number of really cool modules that people don’t know about. These are quite helpful. People often tend to …

Ethics for Platforms

The Internet was created to be an open source to get connected to the rest of the world, to share information and bring the world …

MongoDB (NoSQL Databases)

MongoDB is on of the widely used databases. It is a semi-structured database that stores data in the form of documents (JSON like …

Content Addressed Peer-to-Peer File System for the Web with Blockchain-Based Metadata Integrity

With the exponentially scaled World Wide Web, the standard HTTP protocol has started showing its limitations. With an increased amount …

Recent Publications

Summarizing and Analyzing the Privacy-Preserving Techniques in Bitcoin and other Cryptocurrencies

We summarize the privacy preserving techniques used in Cryptocurrencies and compare them to Bitcoin.

End-to-End Lung Cancer Diagnosis on Computed Tomography Scans using 3D CNN and Explainable AI

We propose a new way of creating a unified interface for radiologists & researchers to analyze CT scans and support the system with …

Content Addressed Peer-to-Peer File System for the Web with Blockchain-based Metadata Integrity

We propose a new content addressed peer-to-peer file system as a replacement to the bloated HTTP protocol assisted with the robust …

Using Generative Adversarial Networks for Secure Pseudorandom Number Generation

We propose a new way of generating pseudorandom numbers using generative adversarial networks. We demonstrate that a GAN can act as a …

A Secure Password Manager

We propose an offline password manager, that does not store passwords anywhere. These passwords are not even stored on the device of …