Achieving wireless communication security exploiting the inherent properties of the physical layer is a promising field. Received signal strength (RSS) based key generation is one of the physical layer security technique in which the inherent channel randomness is exploited in the form of RSS. In this paper, we reviewed the RSS based physical layer secure key generation and analyzed the bit disagreement (BDR) performance of the system. We also compared the BDR performance of the system employing different quantization schemes. Based on the simulation results, we conclude that the Lloyd Max based quantization outperforms among them. Further, the system performance can be improved by using common quantization parameters at both the legitimate nodes. NIST test verifies sufficient randomness in the generated secure keys. The paper concludes with some open issues in this domain for future research.