The global shift toward cashless payments is accelerating, with credit cards remaining popular due to their convenience. However, current credit card payment systems face challenges, including security risks from transmitting card data in plain text during authorization, system interruptions from relay center failures, and payment delays due to network latency, particularly in cross-border transactions. While security measures like PCI DSS compliance and tokenization help protect cardholder data, they do not fully prevent unauthorized access by malicious employees at relay centers. Efforts to enhance availability, such as offline payment systems and blockchain-based solutions, struggle with compatibility with existing financial infrastructures. To address these challenges, the authors propose a credit card payment scheme using Trusted Execution Environments (TEEs). In this system, payment terminals, relay centers, and issuer servers process transactions within TEEs, ensuring that sensitive card information is not exposed. Additionally, the scheme offloads some authorization tasks from the issuer to the relay center using a conflict-free replicated data type (CRDT) approach, improving system availability even without a direct connection to the issuer. Implemented on Azure’s Confidential Computing, this system demonstrated a 72% reduction in processing time during network delays, enhancing both security and performance while maintaining compatibility with existing infrastructure.