Security against individual attacks for realistic quantum key distribution

Key Points

• The aim is to establish security in quantum key distribution against individual attacks under realistic signal sources.
• Developed a proof for security using weak coherent pulses and down-conversion sources.
• Applied it to the Bennett-Brassard 1984 protocol with a standard detection scheme.
• Derived a formula for secure bit rate per time slot to optimize performance.
• The proof ensures the security of quantum key distribution protocols against individual attacks.
• A formula for secure bit rate was obtained, fostering optimization of existing schemes.
• Demonstrated that realistic sources can maintain effective security in quantum communications.