QUANTUM CRYPTOGRAPHY: SECURING DATA IN THE POST-QUANTUM COMPUTING ERA – A COMPREHENSIVE EXPLORATION OF THE FUTURE OF CYBERSECURITY

Classical cryptographic systems face a hazardous situation because quantum computing operates as a threat vector against classical systems through Shor's and Grover's algorithms. Through Shor's algorithm factoring large integers results in a breach of RSA encryption methods whereas Grover's algorithm enables substantially quicker searches of unsorted databases to diminish symmetric key encryption strength. The advanced features of quantum systems eliminate the foundation of security that classical cryptographic techniques depend on computation complexity for protection. Quantum Key Distribution (QKD) under the principles of quantum mechanics presents an effective solution through quantum cryptography for achieving secure communication. QKD stands apart from classical systems through its complete security because attempts at quantum channel interception automatically disable transmitted information and notifies sender and receiver. The successful deployment of quantum cryptography needs solutions for its high implementation expenses coupled with noise sensitivity along with scalability limitations. The research shows it is vital to actively implement quantum-resistant cryptography now because it will protect sensitive data as the post-quantum computing period begins thus securing global cyberspace infrastructure protection systems. The study demonstrates both promising speed benefits of Hash-Based cryptography but Code-Based cryptography encounters deployment barriers because of its performance restrictions. Future studies must focus on performance development of PQC mechanisms to boost operational speed and sustain security standards.