Coinbase CEO Brian Armstrong told CNBC that quantum computing threats to blockchain are "very solvable."

Armstrong describes Coinbase as "front-footed" on the issue. The company is coordinating with major blockchains to upgrade to post-quantum cryptography.

Coinbase recently formed an advisory board to assess these long-term risks.

Coinbase shares showed little change in after-hours trading. Investors view quantum computing as a distant challenge rather than an imminent risk.