Title :
Secret key generation over correlated wireless fading channels using vector quantization
Author :
Hou-Tung Li ; Hong, Y.-W Peter
Author_Institution :
Inst. of Commun. Eng., Nat. Tsing Hua Univ., Hsinchu, Taiwan
Abstract :
Vector quantization schemes are proposed to extract secret keys from correlated wireless fading channels. By assuming that the channel between two terminals are reciprocal, its estimates can be used as the common randomness for generating secret keys at the two terminals. Most schemes in the literature assume that channels are independent over time and utilize scalar quantization on each element of the estimated channel vector to generate secret key bits. These schemes are simple to implement but yield high key disagreement probability (KDP) at low SNR and low key entropy when channels are highly correlated. In this work, two vector quantization schemes, namely, the minimum key disagreement probability (MKDP) and the minimum quadratic distortion (MQD) secret key generation schemes, are proposed to effectively extract secret keys from correlated channel estimates. The vector quantizers are derived using KDP and QD as the respective distortion measures. To further reduce KDP, each channel vector is first pre-multiplied by an appropriately chosen unitary matrix to rotate the vector away from quantization cell boundaries. The MKDP scheme achieves the lowest KDP but requires high complexity whereas the MQD scheme yields lower complexity but at the cost of slightly increased KDP. Computer simulations are provided to demonstrate the effectiveness of the proposed vector quantization schemes.
Keywords :
cryptography; entropy; fading channels; vector quantisation; SNR; channel vector; computer simulations; low key entropy; minimum key disagreement probability; minimum quadratic distortion secret key generation; scalar quantization; vector quantization schemes; wireless fading channels; Channel estimation; Complexity theory; Noise; Training; Vector quantization; Vectors;
Conference_Titel :
Signal & Information Processing Association Annual Summit and Conference (APSIPA ASC), 2012 Asia-Pacific
Conference_Location :
Hollywood, CA
Print_ISBN :
978-1-4673-4863-8