Implementing the decoy state protocol in a practically oriented Quantum Key Distribution system-level model

Abstract

Quantum Key Distribution (QKD) is an emerging cybersecurity technology that exploits the laws of quantum mechanics to generate unconditionally secure symmetric cryptographic keying material. The unique nature of QKD shows promise for high-security environments such as those found in banking, government, and the military. However, QKD systems often have implementation non-idealities that can negatively impact their performance and security. This article describes the development of a system-level model designed to study implementation non-idealities in commercially available decoy state enabled QKD systems. Specifically, this paper provides a detailed discussion of the decoy state protocol, its implementation, and its usage to detect sophisticated attacks, such as the photon number splitting attack. In addition, this work suggests an efficient and repeatable systems engineering methodology for understanding and studying communications protocols, architectures, operational configurations, and implementation tradeoffs in complex cyber systems.

Modeling, Simulation, and Performance Analysis of Decoy State Enabled Quantum Key Distribution Systems

“…The first increment provided a hardware-focused QKD notional architecture built in a modular fashion from a library of optical and electro-optical components with probabilistic weak coherent optical pulses [6]. The second increment added the processes and logic required to execute the decoy state protocol [7,60]. In the third increment, the behaviors of several modeled components were extended to properly handle the propagation of photon number specific representations of optical pulses (i.e., Fock states) and the PNS attack was fully implemented [9].…”

Modeling quantum optics for quantum key distribution system simulation

“…Splitting (PNS) attack against the QKD system. 23 The PNS attack is conducted by an adversarial eavesdropper, Eve, whose purpose is to gain knowledge of the generated secret key. Eve performs the PNS attack by stealing photons from each multiphoton pulse Alice generates while suppressing all single photon pulses.…”

“…Additionally, Alice and Bob's individual processors had to be extended to perform analysis of signal and decoy qubit detection statistics to detect the presence of a PNS attack. 23…”

“…22 In Figure 8, we present a decoy state enabled QKD system model which extended the reference architecture to include the necessary components and behaviors required to perpetrate a Photon Number Splitting (PNS) attack against the QKD system. 23 The PNS attack is conducted by an adversarial eavesdropper, Eve, whose purpose is to gain knowledge of the generated secret key. Eve performs the PNS attack by stealing photons from each multiphoton pulse Alice generates while suppressing all single photon pulses.…”

A module-based simulation framework to facilitate the modeling of Quantum Key Distribution system post-processing functionalities

“…In addition, it demonstrates the diversity and variety of executable simulations (i.e., QKD system configurations), and tests that have been created using the framework. For example, a notional polarization-based prepare and measure BB84 QKD system, 6 a decoy state QKD system, 19 a decoy state QKD system performance in the presence of eavesdropping, 20 and a photon number splitting attack 21 have been modeled.…”