Embodiments of the present disclosure provide a method and a device for data transmission. In the method, a network layer communication entity of a receiving device receives an IP packet from a sending device, where a header of the IP packet carries a random value corresponding to the sending device. The receiving device decapsulates the IP packet and obtains the random value carried in the header of the IP packet. The receiving device sends the random value to a transport layer communication entity of the receiving device so that the transport layer communication entity of the receiving device verifies the random value. The receiving device in embodiments of the present disclosure includes a receiving module, an obtaining module, and a verifying module.