Circle's Arc public chain releases a quantum cryptography roadmap, covering full-stack upgrades from wallets to validators.

Deep Tide TechFlow message. On April 6, according to the official blog, Arc, Circle’s institutional-grade blockchain, released a phased upgrade roadmap for post-quantum cryptography (PQ). It plans to introduce post-quantum signature schemes at the time of mainnet rollout and gradually cover the full-stack layers, including private state protection, infrastructure hardening, and validator authentication.

Arc mainnet will support post-quantum signatures from the beginning of the rollout, using an opt-in mechanism, with no forced migration or full network reset. Users can create wallets with long-term security on their own. The near-term goal is to extend quantum resistance to the private virtual machine (VM) layer, protecting private balances, private transactions, and private recipients. Public keys will be additionally encapsulated with a symmetric-encryption layer under privacy mode. The mid-term plan is to advance infrastructure-layer upgrades to align with industry standards such as TLS 1.3, covering access control, cloud environments, and hardware security modules (HSM). The long-term goal is to complete validator signature hardening. Given that Arc’s block-finality confirmation time is less than 1 second, current assessments suggest that the quantum attack risk for this stage is relatively limited. The roadmap will proceed steadily once the post-quantum consensus tooling pipeline matures.

Circle also warns that attackers may adopt a “collect now, decrypt later” strategy. Institutions should plan their cryptography migration paths as early as possible.