Patent ID: 8843954
Filing Date: 2014-09-23
Classification: H04L,H04N

Abstract:
1. An information transmission method, comprising: a sender receiving a digital broadcasting signal and an Entitlement Management Message (EMM), demodulating the digital broadcasting signal to obtain a data frame, performing demultiplexing to the data frame to obtain a scrambled media data block and an Entitlement Control Message (ECM), using the ECM and the EMM to calculate a Control Word (CW), and using the CW to descramble the scrambled media data block to obtain a clear stream the sender scrambling the clear stream in a predetermined scrambling way to obtain a scrambled stream, and sending the scrambled stream to a receiver; and the receiver receiving the scrambled stream, and descrambling the scrambled stream in a predetermined descrambling way to obtain the clear stream; wherein the sender is a data card, the receiver is a terminal device, the predetermined scrambling way corresponds to the predetermined descrambling way, and the predetermined scrambling way and the predetermined descrambling way are, respectively, encryption and decryption using the same key, wherein the key is preset in the sender and the receiver, or is obtained by using a key agreement mechanism.