Kostas Chalkias On Why Sui Is Betting On Quantum Safety, AI Agents, And Robots, Not Just Faster Transactions

In this episode of When Shift Happens, I sit down with Kostas Chalkias to discuss why the next decade of blockchain won’t be defined by faster transactions, but by quantum-safe cryptography, AI-native infrastructure, and systems designed for machines and humans. Chalkias is the co-founder and chief cryptographer at Mysten Labs, best known for building the Sui Network after leaving Facebook’s Libra project. With over 15 years in cryptographic research and security, he brings a rare mix of deep theory and real-world systems experience to the conversation.

What emerges is not just a technical discussion, but a clear philosophy: most blockchains are optimising for today’s users, while Sui is preparing for a future shaped by governments, AI agents, and even robots.

From Facebook to Founding Sui

Chalkias started his career in cryptography long before it became mainstream, publishing research on post-quantum security more than a decade ago. His time at Facebook, working on Libra and later WhatsApp payments, gave him a front-row seat to what it means to design systems for billions of users.

But that experience also revealed a hard limitation of big tech.

“If I stayed at Facebook,” he explains, “the only way to shine and use my technology in real life was to acquire someone and do the same thing again.” Innovation moved slowly, gated by layers of approval and regulatory paralysis. Libra, despite being technologically ready, never launched.

For Chalkias, building something new became the only real option. “A startup like Mysten is probably my only option to apply the things that I do for humanity,” he says. “There is no other way.”

What Cryptography Actually Does (and Why It Matters)

One of the most grounded parts of the conversation comes when Chalkias explains cryptography in the simplest possible terms.

“Crypto is a Greek word,” he says. “It means something being secret. Graph means I write. So I’m writing something in secrecy.”

That secrecy underpins everything from WhatsApp encryption to digital signatures and zero-knowledge proofs. Cryptography is what allows messages, payments, identities, and data to move without being exposed to intermediaries.

And crucially, it is not static. “Cryptography is evolving,” Chalkias notes. “Something new is always coming, and then we’re working on more complex algorithms.”

That constant evolution becomes critical when you consider what comes next.

Quantum Computing: Panic Later, Prepare Now

Few topics generate as much fear in crypto as quantum computing. Could a sufficiently powerful quantum machine break Bitcoin or Ethereum?

Chalkias offers a calm but nuanced answer. “If you ask me now, in 2025, I don’t see this happening in the next five years,” he says. Early predictions that quantum would break cryptography by 2030–2035 have softened.

But that doesn’t mean the threat should be ignored.

Governments and institutions are already preparing for a post-quantum world, regardless of whether the attack arrives on schedule. As Chalkias explains, if blockchains want to support stock markets, banking rails, or government systems, they will be required to support quantum-safe algorithms.

There’s also a wildcard no one fully accounted for: AI. “We created almost a different species,” he says, referring to how AI accelerates research. AI-assisted breakthroughs could compress timelines dramatically.

His conclusion is that chains should migrate before the crisis, not after. Sui has already begun that work, including mechanisms that allow even existing addresses to upgrade their security using post-quantum zero-knowledge proofs.

Why Sui Looks Different from Other Blockchains

Sui’s design choices stem directly from Chalkias’ experience with real-world systems. Instead of chasing marginal speed improvements, the team focused on structural problems others ignored.

One example is onboarding. Sui allows users to log in with Google or Facebook as a protocol-level capability. “The average Instagram user cannot remember a password,” Chalkias says bluntly. If crypto wants mainstream adoption, UX has to meet users where they already are.

Another is cryptography itself. Chalkias argues that many chains lack strong internal cryptography teams, relying instead on academic research or community initiatives that move slowly. Sui, by contrast, was built by engineers who had already shipped at scale inside Facebook, Apple, and Google.

That background matters when institutions are choosing infrastructure. “If you are a government or a minister and you want to build something,” he asks, “can you go to a team that hasn’t delivered anything in the past?”

AI, Robots, and Non-Human Users

Perhaps the most forward-looking part of the conversation is Sui’s focus on non-human users.

AI agents and robots don’t behave like people. They generate large amounts of data, require low latency, and often need to coordinate multiple actions in a single state update. Sui’s architecture supports larger blocks, faster finality, and programmable off-chain tunnels that allow robots or agents to operate cheaply and safely.

Chalkias paints a vivid picture: real-world robots competing in controlled environments, with users trading prediction markets on the results, or autonomous machines renting themselves out through smart contracts. As fictional as it sounds, these systems are already being tested.

“Sui is better suited for complex technologies,” he explains, because it combines large data handling, encryption, identity, and storage in one unified system. Other chains, he argues, were not designed for this level of complexity.

A Strength That’s Also a Weakness

Ironically, Sui’s biggest weakness may be how much it does well.

“We have so many features,” Chalkias admits, “that it’s impossible to explain all of them in 15 minutes.” Unlike Bitcoin’s “digital gold” or Ethereum’s early DeFi narrative, Sui doesn’t fit neatly into a single category.

But that general-purpose nature is precisely why institutions are paying attention. Stock exchanges, governments, and developers are choosing Sui not because it dominates one niche, but because it sits near the top across many.

Building for the World That’s Coming

Chalkias’ motivation is deeply personal. Growing up in Greece during capital controls, he saw firsthand what happens when trust in financial systems collapses. Crypto, for him, represents resilience.

“We felt it in our blood,” he says. “We needed a change.”

That ethos runs through Sui’s design: privacy with accountability, innovation without silos, and infrastructure ready for a future shaped by AI, institutions, and machines.

While other blockchains fight today’s battles, Sui is preparing for tomorrow’s users, many of whom won’t be human at all.

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