The main objective of this chapter is to study explicit key extraction techniques and algorithms for the security of radio communication. After some recalls on the main processing steps (Figure 19.1(a)) and on theoretical results relevant to the radio wiretap model (Figure 19.1(b)), we detail recent experimental results on randomness properties of real field radio channels. Furthermore, we detail a practical implantation of secret key generation (SKG) schemes, based on the Channel Quantization Alternate (CQA) algorithm helped with channel decorrelation techniques, into modern public networks such as WiFi and radio-cells of fourth generation (LTE, long-term evolution). Finally, through realistic simulations and real field experiments of radio links, we analyze the security performance of the implemented SKG schemes, and highlight their significant practical results and perspectives for future implantations into existing and next-generation radio standards.