Circle just published a whitepaper detailing how its upcoming Arc blockchain will defend against quantum computing threats. The roadmap spans four phases, starting with opt-in post-quantum cryptographic signatures at mainnet launch and culminating in full validator and consensus upgrades by 2030.
Most blockchains today rely on cryptographic algorithms that a sufficiently powerful quantum computer could shatter. BlackRock, Visa, and Mastercard are among the institutional backers of the Arc network.
What Arc actually is, and why quantum matters
Arc is Circle’s Layer-1 blockchain, designed to be EVM-compatible, meaning it plays nicely with existing Ethereum tools and smart contracts. The public testnet went live in October 2025, and mainnet is planned for later in 2026. USDC, Circle’s dollar-pegged stablecoin, will serve as the native gas token on the network.
Based on testnet performance, Arc delivers sub-second finality. For context, Ethereum’s finality currently takes around 12 minutes under normal conditions.
