Kostas Chalkias is a Co-Founder and Chief Cryptographer of Mysten Labs, the company building the Sui blockchain and Walrus decentralized storage. He is the principal cryptography voice across Sui and Mysten Labs infrastructure.
Chalkias previously led or contributed to cryptography work at Meta and other technology organizations, where he collaborated with the engineers who would become the Mysten Labs founding team. His background spans applied cryptography, key management, authentication, privacy and security research.
In 2021, he co-founded Mysten Labs with Evan Cheng, Sam Blackshear, Adeniyi Abiodun and George Danezis. At Mysten Labs he has been responsible for the cryptographic design underpinning Sui's transaction signing, key management, zero-knowledge proofs and privacy primitives, as well as cryptographic architecture in the Walrus storage protocol. He is known by the nickname "Kryptos" in the cryptography community, though this is not his legal name.
Information last checked: August 2026
