The 6-second key delivery time is based on the assumption that the key would be delivered over the air from, for example, a geostationary augmentation satellite. So that was our assessment of how long it would take us to reasonably deliver the signature and not use the entire data channel to do it.” “We need to have enough time to deliver the entire digital signature and still get the rest of the necessary ephemeris data down to the user. The 3-minute channel latency for signal-based delivery is driven by the data rate available on the GPS signal, explained Joanna Hinks, the principal investigator for the AFRL signals research team. The keys can be delivered via the GPS signal itself, which involves a 3-minute delay, or through other faster channels like an augmentation system (6 seconds) or an internet connection (1.5 seconds). “As soon as the keys are published they are no longer suitable for real time watermark generation,” he said. The approach is specifically designed for civil users and does not require them to hold onto keys securely. You can’t see it in real time but you can go back and look at it and establish that that really did come from a satellite,” Scott told Inside GNSS. “Basically what we’re doing is we are coding this into the signal. Either they won’t have the watermarks or the watermarks and key won’t match up. This makes spoofed signals easily detectable. Since the signal is already in the user’s receiver before the key is sent, a spoofer will not have the correct key ahead of the real signal going out. Once a key is sent the system changes the key. The signal is recorded by a receiver and then decoded with a key that is sent after a slight delay. In April AFRL released Interface Specification IS-AGT-100, a new Space Segment/User Segment Interface for the experimental signal and is seeking feedback from the satellite navigation community (see box).Ĭhimera involves encrypted, steganographic watermarks that are encoded into the signal by the satellite. The work is being led by AFRL’s Advanced GPS Technologies program, which is part of the Space Vehicles Directorate. AFRL is adding the experimental signal to the NTS-3 satellite (Navigation Technology Satellite 3), which is set to launch in 2022. The technology Scott proposed is Chimera or Chips Message Robust Authentication, which is now being tested on L1C by the Air Force Research Laboratory. Authenticatable signal architectures are needed.” Chimera “Some of the spoofing detection measures in wide use offer a false sense of security. “The current state of affairs in anti-spoofing receiver design reveals numerous vulnerabilities,” Logan Scott wrote in a 2003 paper introducing the technology. This later capability could enable firms to more easily thwart would-be hackers by blocking those unable to prove they are sending from expected and/or appropriate locations. Version Length Status Hot Creator Updated 4K Hard Lv.23 134 Alpha 1217 basabasa1212 12:24 EXT Lv.29 134 Alpha 14 Niconi 19:47 Dance Cube Hard Lv.29 136 Alpha 198 Khdkah 00:01 Extreme Lv.30 134 Alpha 35 alm0nd 18:09 EXTREME Lv.26 136 Alpha 39 penmawasip 11:34 1174 137 Alpha 30 USUTAKU 21:06 4K VIOLENCE Lv.34 136 Alpha 62 WATAGASHI1 01:35 This is F** king dump 241 Alpha 6 Black-rose 16:26 4K Phantasm (Tiebreaker) Lv.33 299 Alpha 1478 MWCofficial 04:04 Soundmix 134 Alpha 73 Yukina-S 18:56 Hard 134 Alpha 62 YUKUHIRO 14:12 Slide Lv.26 136 Alpha 132 SASAKI3dayooon 07:02 hard 134 Alpha 66 hty_ 18:57 expert Lv23 137 Alpha 62 bebiGreenTea 11:08 Extend Lv.24 116 Alpha 2361 HIROHIRO1224 13:37 4K Search Lv.31 134 Alpha 397 tkdkendo 09:34 Oni☆10 134 Alpha 58 KajikingX 15:08 4K Hard Lv.28 134 Alpha 460 walkingwalkway 14:20 Hard Lv.20 137 Alpha 5-08-04 08:06 Special Lv22 (Two fingers) 137 Alpha 17-08-03 22:29 Normal Lv.19 134 Alpha 1718 Rask 01:40 Easy Lv.10 135 Alpha 164 Rask 01:39 Hard Lv.23 139 Alpha 2837 Rask 01:39 5K 134 Alpha 157 asuniki 20:06 4K Lv.31 136 Alpha 87 20:05 Extreme Lv.23 136 Alpha 57 Anniverse06 06:29 4K Lv15 134 Alpha 264 just_logres 12:40 Hard 134 Alpha 40 akibox 23:25 Extreme Lv.27 134 Alpha 318 kamekooo 22:42 4K Lv.29 134 Alpha 396 Klemme 17:15 Theory Lv.The new technique adds encrypted watermarks to the L1C signal that not only let users know when a signal is being spoofed but also makes it possible to authenticate the location of a GPS receiver to another party.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |