The invention relates to an unsupervised multi-user
physical layer authentication method based on a twin converter neural network, and belongs to the technical field of
wireless communication security. The method specifically comprises the following steps:
system modeling: constructing a dynamic multi-user
wireless communication
system consisting of a plurality of legal sending ends in a mobile state, at least one attacker and a single legal receiving end, and collecting
channel state information (CSI) of each device under a multipath and time-varying channel through
wireless links such as WiFi; carrying out expansion, amplitude calculation and normalization on the collected complex CSI to obtain CSI amplitude samples arranged according to a
time sequence; the method comprises the following steps: constructing CSI of the same legal equipment at adjacent moments into a
positive sample pair based on short-time invariance characteristics of a
dynamic channel, and constructing CSI with a relatively large time interval and / or CSI from other equipment into a
negative sample pair, so as to form an unsupervised contrast learning sample set; the method comprises the following steps: constructing a lightweight twin Transform model CSI-UST, carrying out
linear embedding, position coding and self-attention
feature extraction on a CSI amplitude sequence, and training by comparing a
loss function, so that the CSI feature distance of the same equipment within a short time is converged, and the CSI feature distance of different equipment or moments is greater than a preset boundary; in an
authentication stage, CSI to be authenticated and historical CSI of each legal device are sequentially input into CSI-UST to calculate a feature distance, a source device is determined based on a
distance threshold, a CSI sample of a corresponding device is updated when
authentication succeeds, and a
new device is incorporated into a legal device set when threshold determination fails and upper layer confirmation passes, thereby realizing dynamic expansion without updating
model parameters. The method does not need to depend on the CSI of an attacker or large-scale
annotation data, is low in
model parameter quantity and small in memory occupation, can still keep high authentication accuracy and low misjudgment rate in various dynamic scenes, and is suitable for being deployed in resource-limited
Internet of Things equipment.