Gergely Kalman (Greg)

IT Security Specialist and Founder of Unbuffered

Gergely is a versatile CTO with a wide variety of experience in a lot of different technologies. He is able to design systems from the ground up and carry them through their lifecycle. Having managed his own tech team, he does not shy away from managing others or advising business decisions.


AWS Certified Cloud Practitioner

Amazon Web Services (AWS)

AWS Certified Developer - Associate

Amazon Web Services (AWS)

AWS Certified Solutions Architect - Associate (SAA)

Amazon Web Services (AWS)


Computer Science - BSC

Eotvos Lorand Science University

2005-09-01 - 2007-07-01


I have created my own VPN startup called, which I ran as CTO for three years and CEO for one year.

Real Estate Scraper

I wrote my own scraper for the largest Hungarian real estate website to get amazing deals.

Online Payment Architect, PCI-DSS Consultant

Helped design Escalion's (Lalib successor) system architecture from networking to services to policies and procedures. Advised on secure software practices and developed policies and procedures to keep cardholder data secure. Escalion passed PCI-DSS test and took over Lalib's transactions, which were around $500,000 each day.

PCI-DSS Consultant

Consultation and architectural help provided for Lalibco, which processed more than $500,000 daily for an Alexa top 50 website. Several bugs and security holes were uncovered in their systems. I prepared it for the PCI-DSS audit, which it passed successfully.


Consultant Software and Infrastructure Architect


2020 - 2020

  • Designed and developed the first version of an MVP.

Consultant Blockchain Developer


2018 - 2019

  • Helped guide business and architecture decisions.
  • Refactored a large legacy codebase.
  • Designed and implemented a distributed architecture.
  • Fixed lots of security bugs.
  • Uncovered business - level vulnerabilities.

Co-founder, CTO, CEO

2014 - 2018

  • Designed the network and APIs as well as desktop clients.
  • Singlehandedly designed and implemented the MVP.
  • Ran the company as managing director (CEO).
  • Ran the development team through the company's lifetime.

Head of Media Platform Development

DuoDecad, LLC, Media Platform Division

2010 - 2011

  • Designed and implemented livestream distribution and conversion architecture in Python 3.
  • Integrated several Libav libraries into Python for stream conversion.
  • Detected bugs in Adobe formats and in Libav format.
  • Tuned machines for maximum network performance.
  • Lectured on IT security, MPD's project, and Python programming.
  • Devised a custom event-driven interface with custom socket handling for Python, including FLV format handlers.
  • Worked as the only developer (for the first eight months) on an alternative video streaming platform to Adobe Flash Media Server (primary goal of the media platform division (MPD)).
  • Achieved our goal within a year using unofficial documentation of the protocol and manual reversing.
  • Iterated until peak performance of the cluster was almost 100Gb. With 30 machines, it would have been capable of completely taking over the existing streaming cluster (100+ nodes).
  • Supported on-the-fly transcoding of incoming audio and video.
  • Administered MPD's machines (about 80).
  • Optimized to allow one node to serve more than 100 thousand clients using approximately 10Gbit/s.
  • Researched and assisted in hardware acquisitions for the project.
  • Benchmarked performance and moved heavy-lifting code to C.

IT Security Specialist

DuoDecad, LLC, IT Security Division

2008 - 2010

  • Benchmarked Linux kernel's behavior when presented with high volumes of DDoS traffic. Tuned and patched the kernel to achieve maximum resilience.
  • Ported old OpenSSH fork modifications to the latest version.
  • Devised company policies for PCI-DSS, developed architecture, and held educational sessions as part of IT security staff.
  • Worked as a member of the incident response team.
  • Performed software audits, penetration tests, and stress tests.
  • Developed a network analyzer in C which created real-time statistics of incoming HTTP requests and pinpointed attackers.
  • Assisted our partner company in acquiring Payment Card Industry Data Security Standard (PCI-DSS) compliance.
  • Implemented failover architecture for the main website.

IT Operator

DuoDecad, LLC, IT Security Division

2008 - 2008

  • Helped with administration of several hundred Linux machines.
  • Wrote small scripts in bash for administrative purposes.
  • Led support for kernel and network-related issues.

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