Challenges and Advancements in Quantum Cryptography : Standardization, Security Risks, and Practical Implementations

The advancement of quantum computing poses a direct threat to classical cryptographic systems, necessitating the adoption of quantum-resistant encryption techniques to maintain data integrity, confidentiality, and trust in digital communications. This study presents a comprehensive evaluation of Quantum Key Distribution (QKD) protocols - specifically BB84, E91, and B92 - alongside post-quantum cryptographic algorithms, including lattice-based, hash-based, and multivariate-quadratic systems. These techniques represent two complementary approaches: QKD leverages quantum mechanical principles for secure key exchange, while PQC reinforces classical cryptography against quantum threats using novel mathematical constructs. A comparative analysis is conducted focusing on security robustness, computational efficiency, and deployment scalability. Real-world constraints such as infrastructure limitations, key management complexity, and algorithmic overhead are also critically examined. The paper also investigates the standardization efforts led by NIST, ISO, and ETSI, highlighting current challenges to global adoption, including the lack of interoperability frameworks and varying readiness levels across industries. The findings underscore the need for hybrid cryptographic models that integrate classical and quantum-resistant mechanisms, offering a pragmatic path forward as quantum capabilities mature. Future directions include integrating quantum cryptography with cloud security, advancing homomorphic encryption, and developing quantum-safe blockchain technologies. These innovations are crucial for building resilient cybersecurity infrastructures capable of supporting next-generation applications such as secure edge computing, confidential AI model sharing, and tamper-proof digital ledgers. This research provides timely insights into the evolving cryptographic landscape and emphasizes the urgency of preparing for the quantum future through interdisciplinary collaboration and proactive technological adaptation.