Physical Layer Security (PLS) in 6G networks refers to the use of physical characteristics of wireless channels, such as signal strength, noise, and interference, to enhance data confidentiality and security. Unlike traditional cryptographic methods that rely on algorithms, PLS leverages the inherent unpredictability and randomness of the wireless medium to prevent unauthorized eavesdropping and ensure secure communication.

In the context of 6G, PLS will play a crucial role due to the expected rise in data traffic, ultra-low latency, and ubiquitous connectivity. With the integration of advanced technologies such as massive MIMO (Multiple-Input Multiple-Output), intelligent surfaces (RIS - Reconfigurable Intelligent Surfaces), and non-orthogonal multiple access (NOMA), 6G can create more secure channels that are resistant to interception.

Key techniques for PLS in 6G include:

1. Beamforming: Directing signals in specific directions to avoid leakage to unintended receivers.
2. Artificial Noise Injection: Adding noise to the communication channel to confuse potential eavesdroppers.
3. Secure Transmission Schemes: Designing coding and modulation strategies that inherently provide confidentiality.

The goal of PLS in 6G is to provide security at the physical layer, complementing higher-layer encryption, to create a more robust and resilient communication system that adapts dynamically to the network environment and user demands.