The invention relates to a
physical layer secure transmission method and
system based on dynamic change of a
channel encoding matrix, and belongs to the field of communication
information security. The
system comprises a joint
encoder arranged on a
physical layer of a transmitting end and a joint decoder arranged on a
physical layer of a receiving end, and the transmitting end and the receiving end are communicated through a
main channel. The method comprises steps as follows: a symmetric key obtained through key agreement is shared between the joint
encoder at the transmitting end and the joint decoder at the receiving end on the basis of an existing
key exchange protocol; a basic check matrix generated through optimized construction as well as a matrix extension factor is agreed publicly; joint
encryption and error-control coding is performed on each transmitted
plain text by the joint
encoder, and corresponding code words in bit are obtained; the joint decoder
decodes received code words into received plain texts at the receiving end. The method and the
system can be used for realizing physical layer
information transmission with high secrecy performance and high reliability.