Circle’s Layer-1 blockchain Arc said it will introduce a post-quantum signature scheme at mainnet, giving users a way to create wallets built to withstand future quantum attacks. The update, published Thursday, did not include a launch date for the mainnet.
The move puts quantum resistance into Arc’s base design rather than leaving it for a later retrofit. In blockchain systems, digital signatures are what let a wallet prove ownership of tokens and authorize transactions. That process remains secure against today’s computers, but Arc is designing for a different horizon, one where quantum machines could eventually break cryptographic assumptions that current chains still rely on.
Wallet creation on mainnet will include a quantum-resistant option
According to Arc, users creating a wallet on mainnet will be able to choose a signing method that future quantum computers cannot easily defeat. That changes the starting point for wallet security. Many older blockchains still depend on legacy cryptographic schemes and may need to add quantum protections later through upgrades or patches.
Digital signatures sit at the center of on-chain asset control. When a user sends crypto, the wallet signs the transaction with a key-derived credential, and the network verifies that signature before moving funds. For now, that model holds. Arc’s position is that this may not be enough over the long term if quantum computing reaches the point where private keys can be derived or attacked more effectively.
Quantum risk debate grows as Arc targets institutional users
Arc’s announcement arrives as the industry revisits the long-term exposure of blockchains such as Bitcoin and Ethereum to quantum threats. The report cited Google’s recent work on the subject as a catalyst for renewed scrutiny of digital ledger security. Developers have already spent months discussing early countermeasures, while startups including Postquant Labs are exploring whether quantum hardware could also be used to strengthen blockchain infrastructure.
Building quantum resistance from the ground up may give Arc a clearer pitch to institutions. Its testnet went live in October, and it uses Circle’s dollar-backed stablecoin USDC as the native currency for gas fees. The report said USDC has a market capitalization of about $77.5 billion, second only to USDT, and remains one of the regulated stablecoins favored by institutional participants.
Roadmap extends beyond wallet keys to private financial data
Arc’s roadmap also goes past wallet protection. In the near term, the project plans to use quantum-resistant cryptography to shield private balances, confidential payments, and recipient information. That means the focus is not limited to transaction authorization or key security; it also covers sensitive financial data tied to institutional activity on-chain.
If those features are implemented as described, Arc’s quantum strategy would cover both asset control and payment privacy. Circle has not released a mainnet timeline, but the update shows Arc treating post-quantum protection as a built-in feature at launch rather than an add-on for later.