A functional quantum computer would render all public-key cryptographic protocols (e.g., RSA, Diffie-Hellman), used for secure communication over the Internet, insecure; conversely, QKD could save the Internet and enable secure public communication. Similarly, super-dense coding can potentially double the classical capacity of a channel, if the parties could share EPR pairs in advance.
This project is aimed at a theoretical study of issues in quantum informatin processing, including (1) algorithms for entanglement purification and distillation, (2) Capacity results for various quantum channels, (3) efficient entanglement manipulation and pure state management via local quantum operations and classical communication (LOCC), (4) quantum key distribution using practical systems, and (5) novel informationally-secure quantum cryptographic protocols that only quantum systems might enable, but are not known to exist using classical cryptographic protocols.
