Kostas Chalkias

Kostas Chalkias is the Chief Cryptographer and Co-Founder at Mysten Labs, spearheading cryptographic innovation and building scalable, secure, and privacy-enhancing technologies for the Sui blockchain. Chalkias was previously Lead Cryptographer at Meta, where he oversaw all cryptography work on the Libra project, collaborated with the WhatsApp team on payment encryption and contributed to the development of the Novi wallet.

Prior to joining Meta, Chalkias spent two years as Lead Cryptographer and Blockchain Engineer at R3, where he collaborated with early Bitcoin developer Mike Hearn to implement the world’s first real-world deployment of a quantum-safe signature scheme. 

A leading expert in applied cryptography, Chalkias has authored more than 50 scientific papers and 8 U.S. patents. Notable innovations include Hashwire range proofs, Winterfell ZKP, Sparse Merkle Trees and EdDSA aggregation.

He is also a noted white hat hacker, having publicly exposed vulnerabilities in signature schemes and solvency proofs at some of the world’s largest crypto exchanges. Most recently, he invented the only known system capable of making historical blockchain addresses quantum-safe without requiring asset transfers.

Chalkias holds a PhD in Cryptography, specializing in blockchain-relevant cryptographic primitives. He is committed to educating the next generation of blockchain engineers, teaching Web3 and blockchain security as a professor at the American University of Sharjah.