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When you browse Instagram and find Tony Abbott's passport number

mango.pdf.zone

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Re: When you browse Instagram and find Tony Abbott's passport number

#241

Post by eru »

jacquesm wrote: post #227
thrwyoilarticle wrote: post #212

Earlier quoted context omitted.

>a Gaussian blur is easy to reverse That's the most surprising thing I've read today. I assumed it was destructive.

It's lossy, but not destructive, and a 'sharpen' operation is technically the same as blur but in reverse. So you won't end up pixel-perfect after doing an 'unblur' but you will be able to make out more than you could before.

If you know anything about the probability distribution of likely inputs, it's even easier to reverse with minimal loss.

Eg knowing that the input was black text on white background or a natural image (instead of eg white noise) helps a lot.

Re: When you browse Instagram and find Tony Abbott's passport number

#242

Post by Jugurtha »

jacquesm wrote: post #230
dheera wrote: post #79

Earlier quoted context omitted.

Yup. I wrote a blog post about this a long time ago in 2007, and it was republished in Gizmodo in 2014: https://gizmodo.com/why-you-should-never-use-pixelation-to-h... You can dictionary attack pixelated photos. With Gaussian kernels, besides deconvolution you can sometimes also dictionary attack them if you have the original font and if the kernel is properly normalized kernel (i.e. most gaussian blurs). Although I…

Interesting, thank you for the link. I had a hunch this should be possible but I wasn't aware that it was already proven. I used a similar trick on image recognition: turn images into a single 32 bit word by heavy pixelation and then look up a matching description. It's interesting how often that will work once you feed it with enough data. After all, that gives you 4 billion inputs mapped onto 4 billion descriptions…

I wonder if you could use adaptive optimal kernels, AOK[0]? I had used this for work on multiphase flow recognition from an electrical capacitance tomography, ECT, as a proxy for void fraction. We wanted to tinker with time-frequency representations.

[0]: https://pdfs.semanticscholar.org/20c2/b82eef0809df80a402f125...

Re: When you browse Instagram and find Tony Abbott's passport number

#243

Post by coldpie »

maest wrote: post #196
POiNTx wrote: post #20

Apart from the really interesting content, this is an extremely good read, strikes me as the right kind of balance of information and keeping you entertained. I really enjoyed this writing style!

Since we're sharing views on the writing style - I found it off-putting enough that I had to quit halfway through. It's very tiresome to read, with _way_ too many digressions and jokes.

Yeah, same. "Ok, this paragraph is nonsense, skip it.. so is this one... and this one... why am I still reading this?"

Re: When you browse Instagram and find Tony Abbott's passport number

#244

Post by gus_massa »

function_seven wrote: post #37
kccqzy wrote: post #26

Nice. Here's a similar personal story with a PSA that sometimes blurring is NOT sufficient. A friend of mine posted on Instagram a picture of a U.S. visa (or something similar; it was probably five years ago) to announce her trip to the U.S., and she took care to blur out sensitive information such as her passport number. But a Gaussian blur is easy to reverse and I successfully unblurred it and told her my discovery…

Your advice is good, and I agree that you didn't use specialized software to reverse the blur, but this > I didn't use any specialized software; it was just Mathematica with its built-in ImageDeconvolve function with guessed parameters for the Gaussian kernel. is one of the most HN comments I've come across recently :)

If it is in the installable version now, it will be in Wolfram Alpha in 5 years if you can guess the right command, and in 10 year Wolfram Alpha will just automatically select the blurred part and make a fake unblurred versions of the jpg.

Re: When you browse Instagram and find Tony Abbott's passport number

#248

Post by mannykannot »

rntksi wrote: post #218
hdi8534 wrote: post #171

Earlier quoted context omitted.

The same when you apply to give up vietnamese citizenship, all your info are public on the goverment website (pdf files with name, birthday, current addresss...)

with the way how the government over there works, even if you have those information... there's really nothing much to do with it.

If you are applying to give up Vietnamese citizenship, I would guess that you are no longer living in Viet Nam, so this information might serve as a starter kit for someone to steal your identity?

Re: When you browse Instagram and find Tony Abbott's passport number

#249

Post by dwd »

CPLX wrote: post #187
anon9001 wrote: post #29

Earlier quoted context omitted.

This was really a delight to read. I wonder if the author was raised on 2600. Fantastic stuff. Also visited his page. Does not disappoint: https://mango.pdf.zone/

I was pretty sure after a few paragraphs he was getting his style inspiration from Douglas Adams, but when I got to his line saying “this is widely regarded as a bad move” I became certain. It is an excellent stylistic choice for documenting interactions with commonwealth bureaucracy, of course.

Something Adams incorporated a lot into his stories:

"But look, you found the notice, didn’t you?" "Yes," said Arthur, "yes I did. It was on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the Leopard'."

I did chuckle out loud when I read "For security reasons, we try to change our Prime Minister every six months".

Re: When you browse Instagram and find Tony Abbott's passport number

#250

Post by XCSme »

Amazingly written post, really enjoyable to read!

It's amazing that we have all those security protocols (HTTPS, e2e encryption, secure log-in, etc.) but in the end most of the "hacks" are just people being stupid or manipulated through social engineering.

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