这一讲讨论DAB的数据加密和解密技术以及能量扩散和解扩散。由于DAB是透明的数据传输系统,这里所说的“数据”包括音频广播节目的数据、数据业务的数据、图像信息的数据等等,它们使用相同的加密、解密技术。所谓数据加密,是一种比特方式的变化,这种方式的变化仍使总的数据率保持不变。接收机如果授予了使用权,就知道“密码”,可以使加密的数据流复原,称为解密。加密、解密有时也称为加扰和解扰。加密通常在两种情况下使用,一是节目或数据的提供者要向用户收取费用,通过加密有意限 This talk discusses DAB’s data encryption and decryption techniques as well as energy diffusion and de-diffusion. Since DAB is a transparent data transmission system, “data” as used herein includes audio broadcast program data, data service data, image information data and the like, which use the same encryption and decryption technology. The so-called data encryption, is a bit-by-bit changes, this approach is still the overall change in the data rate remains unchanged. The receiver, if granted the right to use, knows the “password,” which allows the encrypted data stream to be restored, called decryption. Encryption, decryption, sometimes called scrambling and descrambling. Encryption is usually used in two situations, one is that the program or data provider charges the user, and the limit of encryption