On-chain analyst ZachXBT revealed that stablecoin issuer Circle has blacklisted the cUSDC (Confidential USDC) contract of Ethereum-based privacy protocol ZAMA. According to ZachXBT, the measure was taken about 7 hours ago, resulting in the freezing of approximately $12.6 million worth of USDC within the contract. He explained that the cUSDC contract address is the one publicly listed on ZAMA's official documentation and block explorers. Meanwhile, the specific reason for Circle freezing the related USDC has not yet been confirmed.