Method for generating consistent cryptographic key based on wireless channel features

A method for generating a consistent cryptographic key based on wireless channel features, characterized by comprising:

• (1) according to a preset channel estimate method CE, both communication ends A and B respectively performing channel estimate to a current channel, obtaining channel estimated values ĥa, ĥb and channel estimate mean square error MSE, and defining MSE=f1(CE,γ) according to current channel Signal-to-Noise ratio (SNR) γ, where f1 represents a relational expression between the current channel Signal-to-Noise ratio γ and the channel estimate mean square error MSE when using the channel estimate method CE;
• (2) according to a preset quantization mode and quantization step, performing quantization encoding to the obtained channel estimated values ĥa, and ĥb respectively, thereby obtaining quantized channel eigenvectors {tilde over (h)}a and {tilde over (h)}b;
• (3) letting inconsistency between the channel eigenvector {tilde over (h)}b of end B and the channel eigenvector {tilde over (h)}a of end A, i.e. {tilde over (h)}b={tilde over (h)}a+e be equivalent to obtaining {tilde over (h)}b at end B through virtual channel noise adding the channel eigenvector {tilde over (h)}a sent by end A, where SNR of the virtual channel is
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• wherein e represents total quantization error of channel estimate results of ends A and B, and MSEQ represents quantization mean square error that is decided by the quantization step;
• (4) according to the virtual channel SNR Γ, determining a proper encoding mode ENC such that its error correction performance matches expected bit error rate BER, i.e. ENC=f2−1(BER,Γ), wherein f2 represents a relational expression between the virtual channel SNR Γ and the bit error rate BER in a coding mode ENC, and f2−1 represents the inverse operation of f2;
• (5) end A coding the channel eigenvector {tilde over (h)}a using the determined coding mode ENC and thereby obtaining a check sequence Pa;
• after receiving Pa, end B inputting Pa together with the channel eigenvector {tilde over (h)}b in the end into a decoder corresponding to ENC for decoding, and thereby obtaining an estimated value {tilde over (ĥ)}a of {tilde over (h)}a;
• and
• (6) end A and end B applying a cryptographic key generating function on {tilde over (h)}a, and {tilde over (ĥ)}a respectively to obtain a cryptographic key Kc, wherein Kc=f3 ({tilde over (ĥ)}a,N) wherein N is the length of the cryptographic key and f3 is the cryptographic key generating function.