Blockchain Developer

Bogdan Spasennikov

System Administrator & Blockchain Developer

Blockchain developer with 15+ years in IT, specializing in blockchain technology since 2017. Expertise in building decentralized systems, optimizing consensus protocols, and delivering production-grade blockchain infrastructure. Proven track record in protocol development and system architecture.

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English (B1), Dutch (A1), Russian (Native)
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01

About Me

15+ years in IT, blockchain specialization since 2017

Blockchain Developer and System Administrator with primary expertise in C/C++. 15+ years in IT industry, with blockchain specialization since 2017. Experience crafting production systems in blockchain technology, distributed networks, and infrastructure management. Worked with Rust, Go, and Flutter projects, adapting to existing codebases and implementing required features.

Known for delivering complex blockchain solutions, leading technical initiatives, and driving protocol-level innovations. Passionate about building secure, scalable systems and contributing to open-source blockchain projects.

Core expertise includes architecting Proof of Work consensus protocols, engineering custom Bitcoin P2P messaging implementations, developing cryptographic transaction signing systems, and building production-ready wallets supporting multiple blockchain networks.

Blockchain Development

Architecting Bitcoin forks, designing consensus protocols, implementing cryptographic systems

System Administration

Windows/Linux server management, network infrastructure configuration, virtualization

Atomic Swaps & DEX

Building decentralized exchanges with Atomic Swaps, supporting multiple UTXO blockchains

02

Professional Experience

15+ years in IT, blockchain development since 2017

2017 – Present Current

Blockchain Developer

  • Built production-ready Bitcoin fork with full-featured wallet and blockchain node:
    • Configured network parameters including block time, block size limits, difficulty adjustment algorithm, and genesis block.
    • Implemented fork-specific consensus rules and validation logic, adapting Bitcoin Core's consensus mechanisms.
    • Developed full node implementation with complete blockchain synchronization, transaction validation, and peer-to-peer network connectivity.
    • Built wallet application with secure key management, transaction creation, and support for fork-specific address formats.
    • Configured and deployed seed nodes, established bootstrap mechanisms, and maintained network connectivity.
    • Adapted RPC API interface for fork-specific functionality and custom command set.
  • Contributed to Rust-based DEX platform backend components. Modified existing Rust codebases to implement required functionality, features, and bug fixes.
  • Contributed to frontend development of DEX platform written in Flutter. Modified existing Flutter codebases, delivering necessary updates, bug fixes, and feature modifications.
  • Architected cross-platform GUI using Qt framework, delivering consistent user experience across Windows, Linux, and macOS.
  • Developed comprehensive automation infrastructure, taking on various automation tasks and implementing solutions through Bash and Python scripts. Built CI/CD pipelines using Jenkins and GitHub Workflows, automated testing processes, build workflows, deployment automation, and various development support utilities.
  • Contributed to production DEX platform development based on Atomic Swaps:
    • Role: System Core Engineer, Tester, Code Reviewer, Release Master.
    • Technologies: Bitcoin scripts, HTLC, cross-chain UTXO blockchain interactions.
    • Contributions: Backend (core) components and frontend (GUI) development.
    • Key Contributions:
      • Conducted security reviews and code analysis of atomic swap protocol implementations and cross-chain transaction mechanisms.
      • Performed analysis and testing of multi-blockchain support architecture, covering implementations for major networks including BTC, LTC, DASH, and ZEC.
      • Collaborated with QA team on bug identification and resolution across backend and frontend components, providing technical insights on system architecture, protocol optimization, and implementation details.
2006 – 2017

System Administrator and Technical Support Specialist

  • Architected and maintained Windows and Linux server infrastructure, achieving 99.9% uptime across production environments.
  • Designed and managed network infrastructure including routers (Dlink, Zyxel, Mikrotik), switches, and firewall systems (ufw, iptables).
  • Built multi-branch network architecture using VPN technologies and implemented VLAN segmentation for enhanced security and traffic isolation.
  • Led technical support operations, resolving complex software and hardware issues, and delivered training programs improving team productivity.
  • Created comprehensive documentation and operational procedures, significantly improving support efficiency and reducing resolution times.
  • Architected containerization infrastructure using Docker and LXC, and managed virtualization platforms including VMware, ESXi, Proxmox, and Hyper-V.
  • Built automation systems using Bash and Python, substantially reducing manual operational tasks and improving workflow efficiency.
  • Established comprehensive IT security framework through firewall architecture, security auditing processes, and policy development.
  • Implemented enterprise user management systems, configured GPOs, and deployed roaming profiles enabling seamless resource access.
  • Directed PC service center operations, managing technical teams and delivering exceptional customer service standards.
03

Technical Skills

Comprehensive expertise across multiple technology domains

Code Analysis & Review

Experience with reading, analyzing, and understanding code bases

Bitcoin Core

Code analysis, Bug fixing

Bitcoin Scripting

Understanding principles, Troubleshooting

Proof of Work

Concept understanding

Atomic Swaps

Participation in production-ready project

HTLC

Implementation support

C/C++

Application developmentCode analysis

Rust

Code reading, Targeted fixes

ASM (x86)

Code analysis, Debugging

Reverse Engineering

Code analysis

Targeted Implementation

Experience with implementing specific features and components

Python

Script development

Bash/SH

Automation scripts

Go

Modification of existing code

JavaScript

Targeted fixes

Flutter / Dart

Mobile development

PHP

Backend support, Scripting

MySQL

Basic understanding of query language

LevelDB

Integration support

BerkeleyDB

Configuration, Maintenance

SQLite3

Implementation support

System Support & Maintenance

Experience with system configuration, deployment, and maintenance

Git

Daily usage

Docker

Container management

LXC

Configuration, Deployment

Jenkins

Pipeline(s) setup, Automation

GitLab CI/CD

Basic configuration

Ansible

Script modification

VPN

Configuration, Troubleshooting

VLAN

Setup, Management

Firewalls

Rule(s) configuration

TCP/IP

Basic understanding of network protocols

P2P Protocols

Implementation support

Professional Skills

Experience with team collaboration and professional development

Self-Learning

Continuous learning

Team Collaboration

Process improvement

Mentoring

Knowledge sharing

AI Systems

Productive use

04

Projects

Notable projects and achievements in blockchain and system administration

Decentralized Exchange Based on Atomic Swaps

Contributed to development of production-ready decentralized exchange platform enabling trustless atomic swaps across compatible UTXO blockchains, including major networks such as BTC, LTC, DASH, and ZEC. Worked on HTLC protocol implementation and cross-chain transaction mechanisms, collaborating with development team and QA throughout the process.

Bitcoin scripts HTLC P2P C++
Role: System Core Engineer, Tester, Code Reviewer, Release Master

Full-Featured Blockchain Wallet

Developed cross-platform Qt-based graphical wallet for blockchain ecosystem. Worked on wallet and daemon components for Windows, Linux, and macOS platforms, implementing secure key management, blockchain synchronization, transaction handling, and cross-platform build infrastructure.

C++ Qt Cryptography P2P
Role: Developer

Bitcoin Fork Optimization

Contributed to Bitcoin fork optimization and development, working on performance improvements and security enhancements. Collaborated with development team and QA, implementing required features, fixing bugs, and optimizing existing components.

C++ Bitcoin Core P2P Consensus
Role: Developer

Network Infrastructure Setup

Designed and implemented enterprise network infrastructure connecting multiple branch offices. Built secure VPN architecture, configured VLAN segmentation, and established comprehensive network security policies.

VPN VLAN Firewalls Routing
Role: Network Administrator

Process Automation with Scripts

Built comprehensive automation infrastructure using Bash, Python, and Jenkins-Groovy, streamlining CI/CD pipelines, automating test suites, and developing tooling that reduced development cycle time.

Bash Python Automation Cryptography
Role: Developer

Server Virtualization Infrastructure

Led enterprise server virtualization migration from physical to virtualized infrastructure across VMware, ESXi, Proxmox, and Hyper-V platforms. Optimized VM configurations achieving improved resource utilization and cost reduction.

VMware ESXi Proxmox Hyper-V
Role: System Administrator
05

Additional Information

Languages, interests, and contact information

Languages

English
B1
Dutch
A1
Russian
Native

Open Source & Community

Participation in open-source projects, active Stack Overflow reader.

Additional Interests

AI Blockchain Crypto Reverse Engineering Technical Blogging

PGP Key

72AAEDCBF40CDF58