Alexander Papageorgiou, Developer in Athens, Central Athens, Greece

Alexander Papageorgiou

Cryptography Developer

Athens, Central Athens, Greece
Toptal Member Since
February 3, 2020

Alex is a software developer primarily specializing in blockchain technology, having developed for both commercial applications as well as innovative initiatives. He has spearheaded the development of blockchain applications in European Horizon 2020 projects and worked on building commercial applications, such as a multi-currency account management service that boasted support for over 70 currencies and 13 blockchains.

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WebRTC, MongoDB, Docker, Fastify, Node.js, Angular
Angular, Docker, Node.js, Tendermint, Hyperledger Fabric, Ethereum
Eriden, LLC.
NEO, Litecoin, Dash, Zcash, Nano, IOTA, EOS, ERC-20, Solidity, Bitcoin, Ethereum


Athens, Central Athens, Greece



Preferred Environment

Docker, Visual Studio Code (VS Code), Windows, Linux

The most amazing...

...project I've developed was a decentralized online method through which one can retain a cryptocurrency account with zero-access encryption.

Work Experience

2018 - PRESENT

Software Engineer

  • Developed software for clients who wanted to digitally transform their internal operations primarily consisting of PoCs and full solutions in the form of web, mobile, and desktop applications.
  • Focused on clients in the fintech and healthcare space, while internal tools were developed when necessary for the company. Peer-to-peer protocols were also utilized for streaming data security in a local network between its peers.
  • Achieved the adoption of a zero-access peer-to-peer encrypted messaging protocol as well as local recording techniques for web conferences.
Technologies: WebRTC, MongoDB, Docker, Fastify, Node.js, Angular
2018 - PRESENT

Blockchain Specialist

  • Led the blockchain integration and development on the CHARIOT Horizon 2020 project, where I developed a decentralized PKI cryptographic system.
  • Led the blockchain research and innovation aspect on the ICONET Horizon 2020 project, where I developed a purpose-built blockchain for PI logistics using contract arbitration via Ricardian contracts.
  • Worked on several European projects on the proposal stage to meaningfully introduce blockchain technology.
  • Contributed to several publications for the aforementioned projects and have presented in major conferences such as IEEE CAMAD 2019.
Technologies: Angular, Docker, Node.js, Tendermint, Hyperledger Fabric, Ethereum
2018 - 2019

DLT Technician

Eriden, LLC.
  • Integrated various distributed ledger technologies (DLT) into the payment infrastructure of a banking institution, supporting the provision and complete management of cryptocurrency accounts.
  • Forked library implementations of blockchain clients to properly adjust and interface them with new blockchains not yet added to a library.
  • Coded methods with arbitrary ERC20 and other token-standard tokens that were able to be interacted with via the payment infrastructure. It included the cryptographic generation of blockchain key pairs as well as unique encryption methodologies to secure any operations that involved the private key.
Technologies: NEO, Litecoin, Dash, Zcash, Nano, IOTA, EOS, ERC-20, Solidity, Bitcoin, Ethereum


Arctus Decentralized Zero-access Wallet

Arctus was a project that was developed under a startup accelerator that later developed into a free and open-source project. The application is a web interface that allows you to create a cryptocurrency account for over 80 currencies and 12 blockchains, all while retaining your private key on the client-side throughout the whole process. The key pair is generated via a simple login form of a username and password, thus ensuring that it is easy to remember and can be logged into from any computer.



Go, JavaScript, Solidity


React Native, Tendermint, Fastify, Nano, Angular, Truffle


CockroachDB, MongoDB


Hyperledger Fabric, Docker, Windows, Ethereum, Blockchain, Linux, Visual Studio Code (VS Code)

Industry Expertise



WebRTC, Node.js


Bitcoin, ERC-20, EOS, IOTA, Zcash, Dash, Litecoin, NEO, Cryptography


2016 - 2019

Bachelor's Degree in Computer Science

Athens University of Economics and Business - Athens, Greece