Circle pushes blockchain Arc to be quantum-resistant, Q-Day may arrive before 2030

According to ChainCatcher, stablecoin issuer Circle stated that its upcoming Layer 1 network, Arc, will be designed with quantum resistance as a core objective, emphasizing that long-term cryptographic security has become a “baseline requirement” for financial infrastructure. “Q-Day” (the critical point when quantum computing can break public key cryptography) could arrive before 2030, or even sooner. At the same time, attackers have already begun collecting data in advance, intending to decrypt it once quantum computing matures, with potential risks already emerging.

The Arc testnet went live in October 2025, and the mainnet is expected to launch within the year. In its initial phase, it will support quantum-resistant signature schemes, allowing users to create quantum-resistant wallets (not mandatory). In the future, it will also expand to cover transaction privacy protections, including the encryption of balances, recipients, and transaction data. In the long term, Arc also plans to introduce quantum resistance mechanisms at the validator authentication and network infrastructure levels, aiming to build a comprehensive protection system. Circle stated that Arc is intended to offer developers and institutions a practical path for a smooth transition to the post-quantum era, not just a theoretical concept.