# Vladimir Smelov - Blockchain Developer and Security Auditor

<img src="https://i.imgur.com/VYVYxjm.jpg" alt="Sample image" width="200" height="200">

## Contacts

**Telegram (preferred way):** https://t.me/vsmelov
**Email:** [e-mail]
**GitHub:** https://github.com/vsmelov
**LinkedIn:** https://www.linkedin.com/in/vladimir-smelov-25021669/

## Skills

**Blockchain & Smart Contracts**: Solidity, Web3, EVM, Hardhat, Brownie, OpenZeppelin, ERC20, ERC721 (NFT), ERC1155, DEX, ZK-proofs, Layer-2, Diamonds (ERC-2535)

**Security Audits & DeFi**: Security Audit, Architecture, Vulnerability Analysis, Hacking Prevention, Risk Mitigation, Static Analyzers

**Programming Languages**: Python, JavaScript, TypeScript, SQL, Solidity

## About

- 10 years of experience in IT, with 5 years specializing in Blockchain and DeFi.
- Passionate about security audits and ensuring the highest level of protection for blockchain systems.
- Proficient in designing, developing, and auditing DeFi systems.
- Strong analytical and problem-solving skills with a focus on identifying and mitigating risks.
- **Fluent English 🇬🇧.**

## Portfolio

### [Audits examples](https://drive.google.com/drive/folders/19Ae571ay2wdkW1qmFOwqFvCvtPUVdZ_U?usp=sharing)

### GitHub is [vsmelov](https://github.com.vsmelov)
Buuuut, the most interesting recent projects are closed by NDA, so I can’t show them off 🙂

Let me show you how I write code in a test task.

#### Examples of my deployed verified contracts

- MasterChef reward distributor - https://etherscan.io/address/0x877Ec50E446B74058CFA38935CCe83408B71D746#code

- ERC721Marketplace based on eip712 signatires for - https://polygonscan.com/address/0xfbf9ab6ce181488776d81875dcca71c626251b3c#code

- NFT Legislative Initiative for https://theworldstate.io/ - https://polygonscan.com/address/0xac1b70f0a1a976ad9dd5fdf0a83217e49f9e9923#code

Let me know if you need more.

## Work

### Independent Blockchain Security Auditor (part-time)
**Period**: 2020 – Present
**Position**: Independent Blockchain Security Auditor

#### Security Audits

- Conducted security audits for hundreds of smart contracts from ~50 of companies
- Actively participate in the crypto community, contribute to open-source projects, and stay up-to-date with the latest hacking techniques and published security breaches.

#### Common vulnerabilities found
- Reentrancy attacks
- Integer overflow and underflow
- Time manipulation attacks
- etc

#### Sniper bot for DEX
- front-running and sandwich attacks.
- mitigation of the risk.

#### FlashBots - block manipulations
- FlashBots on the Ethereum network and usage for NFT-related hacks.

#### Deep gas optimizations
- Optimized smart contracts for efficient gas usage using Merkle Trees, Inline Assembly, Diamonds EIP-2535, etc.

#### Additional accomplishments
- Implemented various testing methodologies, such as parameterized tests, equivalence class partitioning, boundary value analysis, and random test scenarios to ensure smart contracts function as intended.
- Transaction verification server that uses Tenderly simulation and anomaly detection to verify transaction results before execution, improving overall security.

### Narfex P2P Exchange
**Period**: 2022 – 2023
**Company**: [Narfex](https://narfex.com/)
**Role**: Senior Solidity Developer
**Project**: P2P crypto/fiat exchange
**Responsibilities**:
- fiat P2P and Oracle contracts.
- MasterChef farming contract.

### DAO NFT State - [The World State](https://theworldstate.io/)
**Period**: 2022
**Role**: Blockchain Architect
**Project**: Citizenship Governance System for a Decentralized State
**Responsibilities**:
- Designed a decentralized state, which included citizenship, parties, presidential elections, and voting for various legislative documents.
- Implemented the system using Solidity, with 7,000 lines of code and 25 smart contracts extendable with Diamond patter.

### [Via.Exchange](https://via.exchange/) Cross-chain Router
**Period**: 2022
**Company**: [Via.Exchange](https://via.exchange/)
**Role**: Senior Blockchain Developer & Security Engineer
**Project**: Cross-chain Router for Easy DeFi Operations
**Problem**: Users have to do many steps when doing cross-chain operations manually (swap -> bridge -> buy -> wrap, etc.), and atomic execution is not guaranteed.

**Solution**:
- Designed a secure cross-chain data transfer protocol
- Developed and tested smart contracts and backend systems, making sure the safe execution of cross-chain operations in one transaction
- Created a cross-chain limit order protocol with an off-chain orderbook based on cryptographic signatures, ensuring atomic finality
- Developed Contract Adapters for dozens of DeFi projects.

**Results**:
- Improved security and efficiency for thousands of users, making their experience better
- Allowed smooth cross-chain DeFi operations, handling millions of USD in volume

### GameFi 3D Shooter - MASD.GAMES
**Period**: 2021 – 2022
**Role**: Middle Blockchain Developer
**Project**: First 3D Shooter with Blockchain ERC20/ERC1155 Economy

**Problem**: 2D GameFi lacks excitement and high-quality graphics for shooter players.

**Solution**:
- Designed the project architecture with a focus on security and scalability
- Developed tokenomics and presented to investors
- Integration with the Unity 3D engine
- Successfully passed Launchpad ICO

### Profiterole Group
**Period**: 2020 – 2021
**Website**: https://profiterole.group/
**Position**: Middle Solidity Developer

- **NFT Marketplace Development**: Developed a successful NFT marketplace with a market cap of approximately $100 million. Key responsibilities included designing tokenomics, developing smart contracts, integrating with OpenSea, caching events, setting up CDN and backend, and ensuring seamless frontend Web3 integration. The project successfully passed the CERTIK audit.

- **NFT Collection Launch**: Managed the launch of various NFT collections by developing tokenomics, smart contracts, and integrating with OpenSea and Web3. I was also responsible for handling the reveal and generation process for the collections.

- **Chain Bridge**: Contributed to the development of a secure and efficient cross-chain bridge to facilitate the transfer of assets between multiple blockchain networks. Implemented token locking, minting, and burning mechanisms and ensured compatibility with various EVM-compatible chains such as Ethereum, Binance Smart Chain, and Polygon.

- **Decentralized Exchange (DEX) Development**: Worked on creating a DEX that allowed users to trade tokens directly from their wallets, utilizing an automated market maker (AMM) model for liquidity provision. Developed smart contracts for token swaps, liquidity pools, and staking rewards.

### MixBytes
**Period**: 2019 – 2020
**Company**: [MixBytes](https://mixbytes.io/)
**Role**: Middle Smart-Contracts Security Auditor

**Responsibilities**:
- Top DeFi Project Audits: Curve.fi (tvl $20b), NuCypher ($1b cap), 1inch, Sushiswap, and dozens of others (examples).
- Critical Bug Discovery: Identified and reported critical vulnerabilities in well-known smart contracts, written in Solidity and Vyper.
- Secure DeFi Development Practices: Utilized industry best practices for secure DeFi development, ensuring the safety and reliability of audited projects.
- Risk Mitigation: Actively mitigated risks by staying updated on the latest hacks and security breaches, applying this knowledge to improve the security of audited projects.

### [BlockTech B.V.](https://block-tech.io/), Amsterdam
**Period**: 2018 – 2019
**Project**: crypto options trading
**Position**: Senior Python Developer

- Created a cryptocurrency trading-bot (Python, asyncio, Elasticsearch, Solidity).
- Created a front-end for the trading-bot (Angular, Node.js).
- Developed a smart contract for derivatives DEX for options trading (Solidity), which keeps track of delta and vega, and liquidates if necessary.
- [VIDEO of statistical arbitrage](https://drive.google.com/file/d/1FyDlcaqoLqIsWAr-GiPtLEXhCR5HHpQE/view).

### OSA Hybrid Platform [(osahp.com)](https://osahp.com/)
**Period**: 2017 – 2018
**Position**: Middle Big-Data Engineer

The system manages supermarkets based on BigData (billions of receipts) - increased sales up to 5%.

- Processed receipts and warehouse data (Spark, ClickHouse, PostgreSQL).
- Designed flexible stores sales reports.

### [Beorg (beorg.ru)](https://beorg.ru/)
**Period**: 2016 – 2017
**Position**: Middle Python Developer

Processing ~50 million handwritten documents annually via computer vision.

- Made the web application (MySQL, RabbitMQ, MongoDB).
- Made a computer scans processing vision system (OpenCV + Feature Detection).

### [GOST-Group (gost-group.ru)](https://gost-group.ru/)
**Period**: 2015 – 2016
**Position**: Middle Python Developer

Marketing integrations for Moscow Metro.
- Backend for the bonus system of Moscow Metro with 20,000,000 users (Python, PostgreSQL, RabbitMQ, Docker).

The application to control the work of ~10,000 cars of Moscow Housing Department:
- Saved billions for the city budget.
- Developed the application (Python + Tornado + Redis + MongoDB + PostgreSQL).

### [Infoskan (infoskan.ru)](http://infoskan.ru/)
**Period**: 2014
**Position**: Junior Analyst

- Marketing research reports.
- Fake questionnaires auto-detection (Matplotlib, graph analysis).

### [Yandex](https://yandex.com/) / AT-Consulting
**Period**: 2013 – 2014
**Position**: Junior ERP Developer

- Integrated Oracle ERP-system to Yandex.
- HUGE database management and optimizations.

## Education

### Moscow State University, Moscow
#### Bachelor of Math - 2013

### TUSUR University, Tomsk
#### Bachelor of Computer Science

## Other
- Winner of international hackathons (ETHOnline, NFTHack, SOLANA)
- Conference lecturer.
- Fire-show performer 🕺🔥
- Visited 40 countries.