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The US Military Quietly Turned GPS Into a Global 'Numbers Station,' Evidence Suggests

1 month 3 weeks ago
A security researcher says evidence suggests the U.S. military has been using an obscure GPS message field for nearly 20 years to broadcast encrypted key-distribution data, effectively turning GPS satellites into a global "numbers station." The hidden-looking 176-bit messages appear tied to the Pentagon's Over-the-Air Distribution system for remotely updating cryptographic keys, meaning ordinary GPS receivers may have been receiving the traffic all along without anyone outside the military noticing. The findings have been detailed by Steven Murdoch, an information security expert, in a new article in Inside GNSS. 404 Media reports: [...] From the beginning, he suspected that the subframe field contained encrypted transmissions because the data was so random. "Random data is actually very unusual to get in nature," Murdoch said. "If you see it, either it's been carefully designed to be random -- but then, why is someone sending out random data? -- or it's encrypted data. I thought encrypted data is by far the most likely explanation." He returned to the subframe on and off over the years, and solicited guesses about its content on Stack Exchange in 2023. Ahmed Kamruddin, a master's student at UCL, developed the project further in 2025. Then, this year, Murdoch put the last pieces of the puzzle together over several weeks by analyzing open archive Global Navigation Satellite System (GNSS) recordings collected since 2007 and kept by GFZ Helmholtz Centre for Geosciences. This dataset included more than 12 million observations of Subframe 4, Page 17, yielding 3,994 unique 176-bit messages. Within this corpus, Murdoch pinpointed key-repeating "sentinels" including a pattern that appeared in February 2010 and was broadcast on and off across dozens of satellites for more than a decade. Murdoch discovered that this particular sentinel was transmitted by all 31 operational satellites within a window of a few hours on May 26, 2011, potentially heralding the activation of a new operational system. He confirmed that this timeline coincided with the rollout of the military's Over-the-Air Distribution (OTAD) and the Over-the-Air Rekeying (OTAR) by cross-referencing declassified documents, including a 2015 presentation about the dates of the operation. "There was a perfect match between the timeline and that presentation and the change points that were automatically identified from the data," Murdoch said. "That was the smoking gun that made me think: This is what it's for." These automated systems replaced the cumbersome manual distribution of cryptographic keying material, allowing military GPS receivers around the world to be rekeyed remotely through satellite broadcasts rather than through onsite procedures. For the next 11 years, this expansive rekeying operation was overlooked in public GPS data. In 2022, the system entered a new phase, according to Murdoch's analysis. The shift was characterized by a slowing in the message rotation rate. Later, in December 2023, broadcasts carrying a distinctive "TEXT" prefix emerged then gradually spread across the constellation. Murdoch isn't sure what explains the recent transition, though it could be a possible modernization of the infrastructure or the introduction of a new protocol. But to him, the bigger takeaway is that the signals were always available for anyone willing to take a closer look, a discovery that suggests that there could be more revelations hidden for the cryptographically curious among us. "Every receiver in the world decodes Subframe 4, Page 17," Murdoch said in his new article. "Almost none of them have ever looked at it. The lesson generalizes: There is more to learn from the bytes already arriving at our antennas than from the bytes we wish were specified differently. The data are publicly available. The signal is overhead, twice a day, every day."

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Google Will Pay SpaceX $920 Million Per Month For Compute

1 month 3 weeks ago
Ahead of its upcoming IPO, SpaceX announced that Google will pay the company $920 million per month for access to roughly 110,000 Nvidia GPUs and related compute infrastructure. Google says the agreement is short-term "bridge capacity" to meet stronger-than-expected demand for Gemini Enterprise, while SpaceX is using deals like this and its Anthropic contract to bolster its pitch for a historic public offering. TechCrunch reports: The deal is similar in length and scope to the one SpaceX announced with Anthropic in late May. As part of that deal, Anthropic agreed to pay SpaceX $1.25 billion per month through 2029 to rent all the available compute from its Colossus 1 data center near Memphis, Tennessee that xAI -- now part of SpaceX -- originally built for its own artificial intelligence efforts. Google's deal appears to be paying for roughly half the amount of compute that Anthropic has access to at Colossus 1. SpaceX didn't say which specific data center Google would be using. CEO Elon Musk has previously suggested his company would reserve the Colossus 2 data center for xAI. Anthropic was significantly limited in its compute capacity prior to its deal with SpaceX, raising usage limits on the same day the deal was announced. Google is in a very different position, with some estimates naming it as the world's largest single owner of AI compute. [...] Also like the Anthropic deal, the agreement with Google includes a cancellation clause. Both SpaceX and Google have the option to terminate the agreement with 90 days notice after December 31, 2026. Google's access to the data center will ramp up "through September at a reduced fee," according to the filing. "If we fail to deliver access to the committed amount of GPUs by September 30, 2026, then following a one-month grace period, Google may immediately terminate the agreement or accept the number of GPUs provided" with a reduction in the monthly fees, it reads.

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