Method and system for safely decoding transponder message

The safe decoding method for the transponder message comprises the following steps: S1, receiving a message code stream sent by a transponder antenna and printing a timestamp on the message code stream; s2, searching a complete first scrambling code message from the received message code stream; s3, recording data of a specific code bit in the first scrambling code message; s4, decoding the first scrambling code message to obtain a user message; s5, generating a corresponding first code for the data of each code bit in the user message; s6, performing inverse solution on the user message based on the data of the specific code bit to generate a second scrambling message; and S7, based on the first check code in the first scrambling code message and the second check code in the second scrambling code message, generating a corresponding second code for the data of each code bit in the user message, and providing the second code for the vehicle-mounted train control system to use. The invention also provides a sa