As global financial ecosystems become increasingly digitized, the need for secure, resilient, and interoperable frameworks to protect cross-border transactions and digital financial identities has grown exponentially. Traditional perimeter-based security models have proven insufficient in addressing the sophisticated cyber threats targeting financial networks, especially in decentralized and multi-jurisdictional environments. This has spurred the adoption of Zero Trust Architectures (ZTA)—a paradigm that assumes no implicit trust across networks, devices, or users—and mandates continuous verification at every interaction point. While ZTA enhances access control and minimizes attack surfaces, it faces implementation challenges in distributed financial infrastructures due to trust management, data integrity, and auditability concerns. Simultaneously, blockchain protocols—with their decentralized consensus, immutability, and cryptographic assurance—have emerged as powerful enablers of secure, transparent, and tamper-resistant financial systems. This article explores the convergence of ZTA and blockchain technologies as a transformative strategy for enhancing the confidentiality, integrity, and availability of cross-border payment systems and digital identity frameworks. It examines how smart contracts, decentralized identifiers (DIDs), and distributed ledgers can reinforce ZTA principles such as least-privilege access, continuous authentication, and micro-segmentation in a decentralized context. Drawing on real-world use cases and regulatory insights, the study proposes a layered security model integrating ZTA with permissioned blockchain infrastructures, highlighting architectural synergies, potential threats, and scalability considerations. It also addresses the interoperability challenges and governance frameworks necessary for adoption in multi-stakeholder financial environments. By bridging trustless identity verification with cryptographic consensus, this integrated approach offers a future-ready blueprint for securing global digital finance in the era of open banking, fintech innovation, and evolving cyber threats.