Circle is advancing its Arc blockchain to resist quantum computing, potentially ushering in "Q-Day" before 2030.

Stablecoin issuer Circle stated that its upcoming Layer 1 network, Arc, will be designed with quantum resistance as its core goal, emphasizing that long-term cryptographic security has become a "baseline requirement" for financial infrastructure. "Q-Day" (the critical point where quantum computing can break public-key encryption) may arrive before 2030, or even earlier. Meanwhile, attackers have already begun collecting data in advance to decrypt it once quantum computing matures, revealing potential risks ahead of time. The Arc testnet went live in October 2025, with the mainnet expected to launch this year. Initially, it will support quantum-resistant signature schemes, allowing users to create quantum-resistant wallets (not mandatory). Future updates will expand to transaction privacy protection, including encryption of balances, recipients, and transaction data. In the long term, Arc also plans to introduce quantum-resistant mechanisms at the validator authentication and network infrastructure levels to build a complete protection system. Circle stated that Arc aims to provide developers and institutions with a smooth, practical path to the post-quantum era, rather than remaining at the theoretical level. (The Block)