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pointertovoid last won the day on December 26 2016

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  1. You can see some images where the magnetic polarisation is read at a small scale, for instance here http://aip.scitation.org/doi/full/10.1063/1.4944951 especially the Fig. 5 http://aip.scitation.org/na101/home/literatum/publisher/aip/journals/content/adv/2016/adv.2016.6.issue-3/1.4944951/production/images/large/1.4944951.figures.f5.jpeg at a perfect scale for hard disk drives.
  2. OK. The argument with the second law doesn't apply and was pseudo-science. The second law has nothing to do with puzzles, and everything to do with entropy, internal energy, temperature, enthalpy and the likes. You know, the integral of dQ/T. Now, the time needed. The attacker doesn't need to read every atom. Once he has found where the information was imperfectly erased on the whole track, that is, a bit outwards or a bit inwards, he needs to read a bunch of atoms per bit only at that imperfectly erased circle. The speed of a tunnel effect microscope can be over 10,000 atoms per second; it would seem logical that spin-sensitive STEM is about as fast, but I don't have the figures. The scale at a Hdd isn't what you describe. If the contiguous read is 150MB/s at 3.5" and 7200rpm, bits are some 20nm long including sync and redundancy, which still makes 100 atoms long, and tracks for 500GB platters are 180nm apart or 1000 atoms. Even if not every atom was oriented (this happens at a bigger scale with several Weiss domains) and some uncertainty remains, reading 100 atoms at one proper radius suffice to get the information free of noise. Nothing of a puzzle here. A badly (=single-pass zeros) erased HDD still contains the sector sync, the redundancy, the information bits recoverable by the spin-sensitive STEM. Once the attacker has read the sectors, he can reconstitute also the folders and files, still well-ordered. Reading a complete 500GB platters is still slow, but we don't have to image individual atoms here, rather groups of 100, and this must be faster. The reading machine being anyway specialized to rotate the platter instead of translating, it can also have many read tips. And since the partition table, partition header and file system is readable, the attacker can read only the files he wants. The spin-sensitive STEM is just the answer to smaller bits and perpendicular recording. All the rest is identical to information recovery on a damaged HDD or a damaged partition and is banal.
  3. Thanks! I'll make a test with Tor at https://panopticlick.eff.org/ . Further observation meanwhile: Paypal refuses to open a session from Tor, so there is some means to distinguish it from other browsers.
  4. I take good note of Nist's statement, paragraph 2.3 on page 6: "Basically the change in track density and the related changes in the storage medium have created a situation where the acts of clearing and purging the media have converged. That is, for ATA disk drives manufactured after 2001 (over 15 GB) clearing by overwriting the media once is adequate to protect the media from both keyboard and laboratory attack." Though, this document is from 2006. Did they have spin-sensitive tunnel effect microscopes back then? https://en.wikipedia.org/wiki/Spin_polarized_scanning_tunneling_microscopy the first referenced article dates from 2009. Such a microscope lets observe the magnetic polarization of single atoms, for instance at locations where the write head put the sensitive data, and that the erase pass didn't overfly accurately enough.
  5. What lets you suppose and even write that? I'm an expert for electromagnetism and hold two MsC for electrical engineering, including microelectronics.
  6. Now that sounds like a pseudo-science argument: "The 2nd law of Thermodynamics describes such a fact." Beware I'm a physicist and I'm easy with thermodynamics, as more people here may be. And citing that law didn't impress me Quite the opposite. Jaclaz has provided articles that did not tell what he claims. In fact, the author of the original paper still recommends presently two multi-pass erase software. Sorry but, after two pages of arguments and references, your one-line strong statement isn't convincing.
  7. And no, I can't find a link, because my memories were wrong. The Tor team recommends Tor as it always did. Complete and sincere apologies. What stays is that the newspaper's blog can presently censor me despite Tor.
  8. Thank you for your well-argumented and documented opinion!
  9. Thank you!
  10. Hello you all! I couldn't find the option to move the "Program files" folder in TeakUI v2.10 (also known as TweakXP) running on Xp as I used to do in W2k, so I moved the folder using TweakUI v1.33 (the one for W2k). Meanwhile the XP works imperfectly, and I don't have the computer at hand to experiment further. Hence the question: Can the "Program files" folder be moved in XP? Is it safe to do this?
  11. Sad, but... From my observations, Tor is defeated in Europe. I'm covertly censored on one newspaper's blog. First noticed as some keywords combined with my name triggered an automatic censorship that raised a false "error 503" (further experiments showed that my messages passed through without my name, or by reformulating the contents, while my name and the keywords repeatably trigger the so-called error 503, even by retrying seconds apart). For some time I could continue posting by using other names. Then my IP address was censored, but I could go on by hiding my IP address using Tor. Just like in any other dictatorship, you know. Since Bernard Cazeneuve's visit to De Maizière and the subsequent European agreement (to combat terrorism of course), even Tor doesn't get through. From my observations, it could be that the European governmental agencies have identified nearly all the nodes of the Tor network. Keep also in mind that the Tor team now advises not to use it.
  12. It wasn't my job and I was questioned over several fully unofficial channels, so I can and do speak about it. The query was about destroying hard disk drives because the owners feared the data could be recovered after erasure. Why they didn't want a multi-pass erasure, I don't know. The query was around 2010, definitely after 2004 and before 2012, but the scrapped disks can perfectly have been older than perpendicular recording - weapons for instance use old hardware often. And given the general degree of paranoia of the people who indirectly asked me how to destroy the Hdd (I strongly suppose the French secret services), it doesn't need a workable method of data recovery: they would destroy the disks just on the remote suspicion of a possibility. This latest linked document supports your claim that perpendicular recording makes one-pass erasure safe. Though, not all technology is known. For instance, tunnel effect microscopes can detect the spin of individual atoms. The latest Pdf's argument was about magnetization force, but tunnel microscopes would read locations where the write head didn't pass exactly over the data to overwrite it.
  13. A single overwrite with zeroes is obviously enough against most attacks. On the other hand, "someone" (which means a secret service or a defence agency) questioned me few years ago over several channels, one of them linked with the French secret services, exactly about how to make disposed magnetic hard disk impossible to read, so at least the interrogation is very real if not the possibility. Also, people should tackle this potential risk depending on who the attacker can be, rather than depending on their own identity or activity. In 2017 you can't reasonably claim that secret services work against terrorists. This is not paranoia, it's thinking honestly within real life. Since overwriting a disk several times is no significant stress - only a big time consumption - I do recommend a safe erase to all people supposing a read attempt by a secret service, just like Peter Gutmann still does in the misquoted paper. ---------- Mind reading machines have been around for at least 30 years, about as long as the imaging radars they probably use to map the brain's activity in real time from a very limited distance. But since one can protect himself against these machines with a tinfoil hat, it's still useful to make disks unreadable, indeed. The study by MIT student is a bunch of nonsense produced by people too little skilled on electromagnetism. They even took argument of the propagation of a magnetic field at 200kHz to infer what should happen to an electromagnetic field at few GHz, the probable band of mind-reading devices. Nor is an attenuation a good argument when the goal is to prevent the acquisition of an image. Interestingly, you can observe how some people tell "tinfoil hat" as a synonym for "whacko". This is a method to suggest that tinfoil hats don't work or address a wrong concern. Better take a few plies of space blanket for you hat: it's more comfortable than aluminium foil and it resists corrosion.
  14. You mean, over 4GB on 32-bit Xp? The Sp3 is a hint to the 32-bit version. So, using the Pae, each task (or application?) can access its own 4GB, like in Server Windows, up to the 64GB Dram, is that it?
  15. Your quote is about using MFM, not about using any method. It stands that the author still recommends multi-pass erasure software. "No attack published" isn't the perfect argument. In 1975 the chief of an embassy's encrypted transmissions invited me in his department and told me about knowing what someone types on the keyboard or reads on the screen through the unwanted radiations. The public heard about "Tempest" in 1995 more or less, and it had been operational meanwhile, since some people used it during their military service. So, yes, things exist that the public isn't aware of, even over decades.