Physical Layer Key Generation (PKG)
Multi-Path Radio Channel Reciprocity Cryptographic Key Derivation
Technique extracting provably secure encryption keys directly from the unique, shared random fluctuations of the physical wireless radio channel.
Technical Explanation
Wireless radio channels exhibit spatial reciprocity: signals propagating between Alice and Bob experience the exact same multi-path fading and phase shifts simultaneously. Because multi-path decorrelates over half a wavelength, an eavesdropper (Eve) located even a few centimeters away sees a completely different channel. Physical Layer Key Generation (PKG) samples these reciprocal channel fluctuations, using quantization, information reconciliation, and privacy amplification to generate identical, unhackable symmetric encryption keys with zero key distribution overhead.
Key Functions
- Generates symmetric cryptographic keys directly from physical radio wave physics
- Operates without complex mathematical public-key infrastructure (PKI)
- Immune to quantum computing decryption because keys are never transmitted over the air
- Decorrelates over half a wavelength, preventing nearby eavesdroppers from deducing keys