Arc, an upcoming layer-1 blockchain backed by USDC stablecoin issuer Circle, has announced that its mainnet launch will include post-quantum signature support. The move is part of a broader roadmap designed to address mounting concerns about quantum computing’s potential to undermine existing cryptographic systems. The Ethereum Virtual Machine-compatible network is specifically aimed at protecting institutional digital assets from future quantum-enabled attacks.
Arc’s quantum-resistance roadmap covers several areas, including wallets, private smart contract state, validator authentication, and supporting infrastructure. The company says its approach is opt-in, requiring no mandatory network-wide migration or disruptive resets. Post-quantum signature support will be available at mainnet launch, while quantum-resistant private state protection is described as a near-term enhancement, and validator signature hardening is identified as a longer-term goal.
The technical demands of implementing post-quantum cryptography are considerable. Classical cryptographic signatures typically measure 64 to 65 bytes, whereas post-quantum signatures can be an order of magnitude larger. Arc notes that its sub-second block finalization limits any attacker to a 500-millisecond window to forge validator signatures, adding a layer of practical protection. The company’s documentation stresses that quantum-resistant protections must be applied across every layer of a blockchain’s stack, not solely at the wallet level.
Arc’s materials also highlight the difficulties facing established networks attempting similar transitions. Migrating Bitcoin‘s existing wallets to post-quantum alternatives alone could require months of continuous processing even under the best conditions, according to Arc’s documentation. The company argues that organizations leading this transition will be those that began building solutions before the threat became urgent, rather than waiting for a crisis to force action.
The broader concept of “Q-Day”—the point at which quantum computers could break public-key cryptography—has been gaining attention across the technology and finance sectors. The National Institute of Standards and Technology has warned of “harvest now, decrypt later” attacks, in which adversaries collect encrypted data today with the intention of decrypting it once sufficiently powerful quantum computers become available. Google has projected that the quantum threat to Bitcoin could materialize as early as 2032, sooner than some earlier estimates suggested.
Other major blockchain ecosystems are also working toward quantum resistance. Bitcoin developers have been discussing mitigation strategies for years, and a Bitcoin Improvement Proposal known as BIP 360 has recently gained traction within that community. Ethereum developers have rallied around a roadmap championed by co-founder Vitalik Buterin and the Ethereum Foundation, with plans to implement quantum resistance before it becomes an active threat. Meanwhile, the price of ALGO rose sharply after the Algorand blockchain was referenced in a Google research paper on post-quantum cryptography.
Most major blockchain networks are currently considered inadequately prepared for quantum threats that could render their existing security measures obsolete. Proactive measures are seen as increasingly critical, particularly for protecting digital assets intended to be held over long periods. Arc’s early integration of post-quantum features positions it as one of the first networks to address these concerns at the infrastructure level from launch.
Originally reported by Decrypt.
