Sam Blackshear, co-founder and chief technology officer of Mysten Labs, is leaving the company. He will join Anthropic to focus on defensive security research. The move was announced by Blackshear himself, and it has already started conversations about how AI and blockchain security intersect.
Blackshear helped create Mysten Labs in September 2021 alongside four former Meta executives. The team later built the Sui blockchain. His departure is a notable shift for the project, but not an unexpected one if you follow his public comments over the years. Blackshear has often said he is most comfortable doing hands-on technical work, and this new role appears to fit that preference.
A change in technical leadership
Mysten co-founder and CEO Evan Cheng will take over the technical vision at Mysten. That is a significant role, but Cheng already has a deep background in infrastructure and systems. The company says its roadmap will stay on track. Blackshear will remain close to the project as an advisor. He also plans to stay involved with the Move Foundation, which supports the Move programming language used by Sui.
It is hard to know what this means for Sui in the long run. Leadership changes at the top of a protocol always carry some uncertainty. Still, Mysten has a large team and a clear set of priorities. The transition looks orderly, and Blackshear is not walking away completely.
Why AI security matters right now
Blackshear’s move to Anthropic comes at a time when AI is playing a bigger role in both defending and attacking software. Security researchers are using AI to spot vulnerabilities faster. At the same time, attackers are using AI to automate phishing campaigns and speed up attacks on blockchain infrastructure. The balance between those two sides is shifting, and Blackshear has pointed to that balance as a reason for joining Anthropic.
His focus on defensive security research suggests he wants to work on the side of protecting systems rather than finding new ways to break them. That is not a small distinction in the current environment. Blockchain networks have become a regular target, and there is no shortage of tools being built to exploit them.
What happens next
For now, Blackshear will stay close to Mysten and the Sui project. That should help with continuity. But his day-to-day work will be at Anthropic, where he will be part of a team trying to make AI systems safer and more resistant to misuse.
It is worth watching how his departure affects Mysten’s technical direction. Evan Cheng has the experience to lead, but the company is still young. Sui has gained traction, yet the broader crypto market remains unpredictable. This is one of those moments where a single hire or departure can feel bigger than it is. Or maybe it really is that big. Time will tell.
