• Photon Number Splitting attack
• Qiskit
• Quantum Computing
• Quantum Key Distribution
• SARG04

In this thesis we conduct an analysis on the SARG04 Quantum Key Distribution Protocol. In the beginning, quantum computing bases are given so that the reader will better understand the topic. Then, SARG04 protocol basics are explained, providing also practical examples. A software implementation code of a self made SARG04 protocol simulator is also provided and explained.
In the second phase, a security evaluation when an active or passive attacker is present is given. We evaluate two attacks: the Photon Number Splitting attack and the Intercept Resend attack.
For both attacks, we provide how much information the attacker gains on the key exchanged between two legitimate parties and the entropy introduced by such an attacker. This is studied with graphs and formulas after a certain number of simulations on the implemented code.
Finally, some real world QKD applications are provided, focusing on QKD used for securing Mobile Networks.