The invention discloses a
mobile phone USIM (
Universal Subscriber Identity Module) side
channel analysis method based on an
outlier. The method comprises the following steps: S1, collecting a
power consumption signal generated in the process of executing an AES (
Advanced Encryption Standard)
algorithm by a USIM card; s2, filtering and aligning the acquired
power consumption signal to generate standardized side channel curve data; s3, for each key
byte position participating in
S box operation in the first round of AES, constructing a
candidate key byte value, and calculating an
S box output value; s4, recognizing recovered and uncertain key bytes by adopting a correlation
energy analysis method; s5, deriving
S box output
byte positions influenced by the uncertain bytes in the second round; s6, calculating the correlation of the candidate value at the position, and generating a correlation
feature vector; s7, inputting a
local outlier factor algorithm, and calculating an
outlier value; and S8, selecting the key byte with the maximum
outlier as a final key byte to form a key byte set. According to the invention, the accuracy and robustness of USIM
key recovery are improved in a low
signal-to-
noise ratio scene.