| 摘要 |
A satellite system comprises first and second devices, one of the first and second devices being a satellite and the other one of the first and second devices being a device arranged to send signals to the satellite and/or receive signals from the satellite. A session key can be distributed in the satellite system by obtaining the session key at the first device, protecting the session key at the first device, based on a private key of the first device and a public key of the second device, and transmitting the protected session key from the first device to the second device. The second device can receive the protected session key from the first device and obtain the session key from the protected session key based on a public key of the first device and a private key of the second device. Replay detection information can be transmitted with the protected session key, for determining whether the session key has been transmitted previously. The protected session key can be transmitted by inserting a predetermined number of bytes of the protected session key into each frame of a data stream, for example a telemetry (TM) data stream as defined in the Consultative Committee for Space Data Systems (CCSDS) TM protocol. Validity information can be transmitted with the protected session key, defining a period in which the session key is valid. The protected session key can be transmitted bonded to a command message, for example a telecommand (TC) as defined in the CCSDS TC protocol. |
