| 摘要 |
An encoder for encoding data broadcast in an MPEG transport stream, of MPEG sections, comprises means for processing the MPEG sections using a hash function (e.g., excluding CRC elements) to provide multiple hash outputs, each associated with one or more MPEG sections by section identifying information. The hash outputs and corresponding section identifying information are signed using a private key corresponding to a public key available at receivers, producing signatures. The hash outputs, section identifying information and signatures are then coded into one or more MPEG sections which are designated signature MPEG sections, which are broadcast in an MPEG transport stream (TS). A receiver verifies using the signature MPEG sections that the MPEG transport stream has been provided by a known (not tampered with) source. Also described is a decoding method, establishing a trusted public key, comprising: periodically receiving one or more broadcast public keys; storing public keys that have been seen on a broadcast channel, and a (e.g., time threshold-based) count relating to the number of times each public key has been received; determining the public key with the highest count; and asserting the highest count (most frequently received) public key as being trusted. |
