Sam Blackshear, co-founder and chief technology officer of Mysten Labs, the team behind the Sui blockchain, has announced his departure from the company to take on a new role at Anthropic focused on defensive security research.
In a series of posts on social media platform X, Blackshear shared that reflecting on his professional journey, he has found the greatest fulfillment in engaging directly with technical challenges while venturing into unfamiliar problem areas.
He described the opportunity at Anthropic as allowing him to pursue both, particularly at a moment when artificial intelligence is altering the dynamics between those launching cyberattacks and those working to stop them.
I am leaving Mysten Labs and joining Anthropic to work on defensive security research.
— Sam Blackshear (@b1ackd0g) August 5, 2026
He expressed strong motivation to contribute to security efforts amid this shifting landscape.
Blackshear is recognized as the creator of the Move programming language, which he originally developed during his time at Meta for the Libra/Diem project and has refined over more than eight years.
After leaving Meta, he co-founded Mysten Labs in 2021 alongside several former colleagues from the Diem effort, including Evan Cheng.
As CTO, Blackshear played a central role in designing the Sui layer-1 blockchain and contributed to related projects such as the Walrus protocol.
He emphasized that Mysten Labs represents one of the strongest groups of colleagues he has worked with.
Although stepping away from day-to-day operations, Blackshear plans to remain a close advisor to the company and to Sui ecosystem developers who reach out for guidance.
He also affirmed his ongoing passion for Move and his eagerness to stay involved with the Move Foundation, which is currently in development to further advance the language.
Leadership of Mysten’s technical direction will pass to co-founder and CEO Evan Cheng.
Blackshear noted that Cheng had personally recruited many of the company’s top technical talent and previously led engineering teams at both Apple and Meta.
He expressed enthusiasm about the path Cheng will chart for the organization.
Blackshear reflected positively on his tenure, describing it as filled with the adventure he had hoped for and imagined.
He offered deep gratitude to the people at Mysten Labs and across the Sui community for their collaboration and support.
The timing of the move aligns with growing attention to how AI tools can both uncover software weaknesses and enable more sophisticated attacks, including those targeting blockchain systems.
Anthropic has been expanding its work on AI-related cybersecurity risks, making Blackshear’s expertise in secure system design and formal methods a notable addition to its defensive research efforts.
While the Sui ecosystem will continue under new technical leadership, Blackshear’s continued advisory role and commitment to Move suggest continuity in key areas of influence. His transition highlights broader industry trends at the intersection of blockchain infrastructure and AI-driven security challenges.
