Леонід

Kyiv, 04108
Ukraine
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Leonid Belyasnik
C++ Developer
Expertise Summary
Profile
C++ developer with commercial experience in software development, maintenance and integration of client-server and distributed systems.
Experienced in C++ development for Windows and Linux, multithreading and concurrency, networking and communication protocols, device integration, Qt/QML applications, databases and supporting infrastructure.
Experience includes device management software, banking and payment systems, security and cryptography software, REST services, IPC, reusable C++ libraries and desktop applications.

Core Skills
• Programming
C++, C++11/14/17
• Operating Systems
Windows, Linux
• Concurrency & Systems
Multithreading, concurrency, thread pools, synchronization, IPC, POSIX API
• Networking & Integration
TCP/IP, sockets, Unix domain sockets, REST, SSH, Protocol Buffers, client-server systems
• Frameworks & UI
Qt, QML
• Databases
Oracle, Firebird, PostgreSQL, SQLite
• Build & Development Tools
CMake, Git, Visual Studio, Qt Creator, CLion
• Testing
Automated testing
• Other
Cryptography, database encryption, device integration

Professional Experience
Developex — Kyiv
C++ Developer
Jan 2019 – Present
• Developing and maintaining software for managing and supporting various hardware devices.
• Participated in the development of an integration layer for a new ecosystem of DIY hardware devices within an existing system.
• Added support for new device types and protocols according to the existing architecture.
• Extended the internal command-based protocol with new GET/SET operations and implemented their command handlers.
• Implemented device-specific functionality across controller and model layers, including communication with devices and models used by the application UI.
• Extended and improved existing base classes where required to support new functionality.
• Developed a large set of Qt/QML UI components, from common controls such as buttons, popups and input fields to more complex application-specific components.
• Introduced a plugin-based approach for UI extensions and developed plugins for the application.
• Implemented specialized UI components, including components involving shader program loading.
• Developed reusable C++ libraries providing common and helper functionality.
• Developed the client application for an internal package management tool using C++ and Qt/QML. The application provided a UI for inspecting available package files, retrieving their metadata and defining the file composition of installation packages. Communication with the server component was implemented over SSH.
• Wrote and maintained automated tests.
• Implemented new functionality, maintained existing code and fixed bugs.
Technologies: C++, C++17, Qt, QML, CMake, Git, SSH

Comodo Group — Kyiv
C++ Developer
Aug 2017 – Dec 2018
CCS for Linux
• Developed and maintained the Linux version of the Comodo security product.
• Reworked the main Linux daemon, removing its dependency on Qt.
• Implemented daemon functionality using worker threads and a condition-variable-based task pool.
• Worked with the existing IPC mechanism based on Unix domain sockets and Protocol Buffers.
• Developed and maintained client-side components and supporting tools.
• Implemented new functionality and fixed issues in the existing C++/Linux codebase.
Technologies: C++, Linux, POSIX API, multithreading, Unix domain sockets, Protocol Buffers, Qt, CMake, Git

Provectus
C++ Developer
Jul 2017 – Jan 2018 (Part-time / additional project)
DeviceManager
• Initiated development of a service for exposing data from a hardware communication layer to web clients.
• Researched different implementation approaches and libraries and selected Microsoft's C++ REST SDK for the REST API.
• Designed and implemented the initial service framework, establishing the technical approach for the project.
• Implemented communication between the service and an existing hardware communication library while providing REST API endpoints for client requests.
Technologies: C++, C++ REST SDK, REST, networking, distributed systems

Cipher Company — Kyiv
C++ Developer / Lead Project Engineer
Mar 2013 – Aug 2017
Worked on banking, security, cryptography and payment-processing software.
• Developed and maintained banking client applications for operators.
• Developed and maintained banking gateway applications for scheduled and automated integration with external banking and payment-processing systems.
• Developed a separate customer monitoring system, primarily using Oracle and stored procedures.
• Participated in testing and evaluation of an in-house cryptographic library, including developing usage examples and validating its functionality.
• Researched and implemented approaches for Firebird database encryption based on the company's cryptographic library.
• Developed Firebird 3.0 encryption plugins and supporting components.
• Developed a prototype database encryption system integrating encryption at the database/plugin level. The technology was researched and presented as a potential solution but was not commercially deployed.
• Developed a PHP extension integrating the company's cryptographic library.
• Developed and maintained banking gateway and integration modules.
Technologies: C++, Delphi, C++Builder, VCL, Embarcadero RAD Studio, Oracle, Firebird, PHP, cryptography, OpenSSL, TCP/IP, multithreading, Windows API, Linux

Intellect-Service — Kyiv
C++ Developer
Mar 2012 – Feb 2013
• Maintained and extended existing C++ applications used for accounting and reporting.
• Implemented new functionality and fixed bugs across several products, including BEST ZVIT+, M.E.Doc and IS-Pro.
• Gained hands-on commercial experience working with large existing C++ codebases.
• Developed a C++ console application for sending developer notifications via XMPP.
Technologies: C++, C++Builder, VCL, SQL, Firebird

Ukrtelecom JSC — Shostka
Software Engineer
Sep 2008 – Feb 2012
• Developed a Delphi-based operator application for remote management and monitoring of Internet club computers via Telnet.
• Implemented remote enable/disable controls and status monitoring for client workstations.
• Developed a prototype web-based system for registering and tracking Internet connection requests.
• Set up and deployed the prototype application on an internal network server.
• Provided system administration and technical support for the branch network and related equipment.
Technologies: Delphi, Telnet, Windows, web technologies

Earlier experience
Self-employed / Freelance
Apr 2008 – Feb 2009
Computer equipment service, maintenance and repair.
PSC Prominvestbank
Apr 2008 – Sep 2008
Automation, system administration, branch network support and ATM maintenance.
Private Enterprise Arkhistyl
Jul 2006 – Sep 2007
Automation tools and system administration.
Additional technical experience
• Oracle and Firebird database installation and configuration.
• Creation of isolated test databases and synthetic data for testing banking software without access to production databases.
• Setup and configuration of supporting services and infrastructure for development and testing environments.
• Experience setting up mail servers and other services to emulate production environments.

Education
Sumy State University
Specialist Degree in Informatics (Mathematician Developer)
2003 – 2009
Languages
English: Intermediate
Ukrainian: Native
Russian: Native