Quantum cryptography and cybersecurity
Vijayakumar Polepally, Ch. Srivardhan Kumar, C. Madhusudhana Rao, T Siva Rama Krishna, Dileep Pulugu · 2025
Cryptography has evolved alongside the development of communication and computing technologies, transitioning from simple manual techniques to complex quantum-resistant algorithms. This journey reflects humanity’s need to secure information in an increasingly interconnected world. The evolution of cryptographic methods highlights humanity’s continuous effort to protect privacy and secure communication. As the world transitions into the quantum era, cryptography must advance to meet the challenges posed by emerging technologies. During the early age, techniques such as Substitution and Transposition ciphers were used. In Substitution Cipher, letters in a message were replaced with other letters according to a fixed rule, and in Transposition Ciphers, the letters of a message were reordered to obscure its meaning. The limitations were that it was easily broken once the substitution or transposition rule was discovered. Subsequently, devices like Enigma machine used rotors for implementing complex substitution ciphers, and the breaking of the Enigma code by allied cryptanalysts marked a turning point in cryptography and cryptanalysis.