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Bert Hubert Profile picture
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24 May, 10 tweets, 5 min read
If you are into reverse engineering, the EU Galileo navigation satellites are currently transmitting a new signal that enables centimeter level accurate positioning. But! They haven't yet released a description of this format, but the data is there & unencrypted. 1/2
Let me know if you want a dump of many hours of data. The data likely includes a distance vector that describes a correction to a satellite's position, plus a velocity vector, plus a time offset correcting the atomic clock, plus administrative details ('issue of data number') 2/2
Ok, the data is here: berthub.eu/galileo/galile…
C/NAV for 2,25,8 means this is a signal from Galileo (2) satellite E25 over E6 (8). Slide 16 and onwards of geopp.com/pdf/gpp_ppprtk… may be helpful.
Feel free to drop by the #galileo IRC channel on irc.oftc.net -> webchat.oftc.net/?channels=gali…, where there is lots of expertise to guide your reverse engineering.
Ok! It turns out an earlier version of a spec is available on the EU eTendering site! I suspect this will be pretty close: etendering.ted.europa.eu/document/docum… from etendering.ted.europa.eu/cft/cft-docume…
If you are trying to make sense of my data, know there is byte order pain in there & also missing data. Best wait it out a bit until I verify it is at least making some kind of sense.
The checksums match the spec! Something is working! Sadly, the satellites are currently broadcasting dummy data.. but at least the checksums are making sense now!
Found the dummy marker AF3BC3 in there! This is a real bitstream protocol that does not respect your byte boundaries. Space protocols tend to be like that.
Actual payload that looks valid! Status 1 = valid data, Message Type (MT) 1 = "Contains satellite
corrections", Message Size (MS) 1 = actually 2 pages per message. Next up, Reed-Solomon!
Some light reading ahead..

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More from @PowerDNS_Bert

Bert Hubert Profile picture
10 May
I love the EU (honestly!), but I also love the Internet. Through the NIS 2 Directive, the EU is attempting to regulate each and every root server operator (RSO), even those outside of the EU. Doing so will have bad consequences. 1/6
berthub.eu/articles/posts…
There are 12 RSOs. There are over 1300 active root servers. None of these RSOs are 'providers of essential services' individually. Up to 11 of them could fail, and nobody would notice. In 40 years, "the root" has never gone down. 2/6
By attempting to regulate the core of the Internet, the EU risks opening up a Pandora's box: many other governments would like to follow suit. The EU itself has advocated for the current multi-stakeholder "governance" model, in lieu of government action. 3/6
Read 7 tweets
Bert Hubert Profile picture
24 Mar
BREAKING! Stanford scientists have analysed the Moderna and BioNTech vaccines to determine the mRNA code in there. This is the first time we are seeing the Moderna sequence. Get it here while it is still online: github.com/NAalytics/Asse…
To see what this means, do head over to this page: berthub.eu/articles/posts…
So how different is the mRNA in the Moderna, BioNTech/Pfizer & CureVac vaccines? There are 1274 codon positions. 808 are identical across all 3 vaccines. 103 are unique to Moderna, 249 unique to BioNTech, 230 to CureVac:
Read 4 tweets
Bert Hubert Profile picture
30 Jan
Recently I learned something about DNA that blew my mind, and in this thread, I'll attempt to blow your mind as well. Behold: Chargaff's 2nd Parity Rule for DNA N-Grams.
If you are into cryptography or reverse engineering, you should love this.
Thread: Image
DNA consists of four different 'bases', A, C, G and T. These bases have specific meaning within our biology. Specifically, within the 'coding part' of a gene, a triplet of bases encodes for an amino acid Image
Most DNA is stored redundantly, in two connected strands. Wherever there is an A on one strand, you'll find a T on the other one. And similarly for C and G:

T G T C A G T
A C A G T C A

(note how the other strand is upside down - this matters!) Image
Read 12 tweets
Bert Hubert Profile picture
31 Dec 20
New leader in the BioNTech vaccine RNA optimization challenge: @pkuhar! With some pretty Python code that can server as a great starting point for other entries: github.com/unrelatedlabs/…. Context: berthub.eu/articles/posts…
New leader @naomicodes, 76% , using DNA Chisel from edinburgh-genome-foundry.github.io/DnaChisel/ - well done!
New leader @sanxiyn! 78.3% using codon frequency optimization.
Read 6 tweets
Bert Hubert Profile picture
31 Dec 20
Reverse engineers! Cryptographers! I have a fun challenge & contest for you. The BioNTech SARS-CoV-2 vaccine contains copy-pasted RNA from the actual virus. The vaccine RNA encodes for (almost) the unmodified virus S protein. But, the RNA has been optimized somehow. But how? 1/
You can change RNA quite a lot without changing the protein that comes out. It is known that replacing RNA letters to G and C to the RNA enhances vaccine efficiency. And lo, the designers of the vaccine have done just that - GC content went from ~36% to ~57%: 2/
In the graph above, the red dots are vaccine changes that _lower_ the number of G and C though. And we don't know why they did that. In other places, it appears simpler rules have been used to optimize the RNA. The goal is now: can we reverse engineer the algorithm they used? 3/
Read 6 tweets
Bert Hubert Profile picture
24 Dec 20
Preparing a blog post on the BioNTech/Pfizer vaccine & compared the live SARS-CoV-2 spike protein to the one in the mRNA vaccine. And indeed as described, it only differs by two amino-acids. The two Proline substitutions that make the vaccine work (KV -> PP, with the !!): 1/3
If the vaccine would have contained the unmodified Spike protein, this would have "looked" different from the real one. The real one is mounted in the virus body, which gives it a certain shape. With these two changes, the vaccine protein "looks normal" to our immune system. 2/3
This proline substitution trick was discovered in *2017* based on studies on SARS-CoV-1 and MERS, two related viruses. These studies noted that this tiny change made the protein *50 times* more recognizable. Iow we'd be toast without this invention ncbi.nlm.nih.gov/pmc/articles/P… 3/3
Read 4 tweets

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