Just Shake Them Together: Imitation-Resistant Secure Pairing of Smart Devices via Shaking

Algorithm 3

Quantization.

Require: 1) The calibrated sensor data sequence with multiple dimension and : ; 2) The length of sensor data sequence: .

Ensure: The bit series: ;

1: for each dimension do

2: Conduct Fast Fourier Transformation over for dimension . Compute the top- principal components in the frequency domain, obtain the highest frequency of these components as .

3: Sample the sensor data for every points, use a sliding window to get the maximum value and the minimum value, normalize the sampled data into the interval [-1,+1].

4: Use the level crossing method to quantize the data sequence , obtain the generated bit series as .

5: For each dimension, break the generated bit series into blocks with variable size according to the specified time line. Merge these blocks from multiple dimensions to bit series in time order.