223

As mentioned in the answers to a very similar question, scribbling over part of an image will destroy the original pixels, assuming that your editor doesn't store any layers or undo history in the saved image. (Paint doesn't.) There are some things to watch out for, though: The width of the blanked region places an upper bound on the length of the secret ...


190

Yes, it can be recovered. As long as shutter does not use layer (it almost certainly does not) and as long as the black is really all black (it must not be transparent), it is enough. The picture that you provided uses some amount of transparency, see here: All I had to do is use the Fill tool in MS Paint. If I used some algorithm that would take the jpg ...


79

You don't even need to use an image editor in this case to recover the "redacted" text. Simply zooming in on the image is enough to read it. So I would say that yes, it most certainly is possible to recover the original text.


72

Yes. If you do a normal format, the old data can be recovered. A normal format only deletes/overwrites a tiny bit of filesystem metadata, but does not overwrite all of the data itself. The data is still there. This is especially true on SSDs, due to wear levelling and other features of SSDs. The following research paper studies erasure of data on SSDs: ...


70

In this case the image can be recovered very well As others already pointed out the dark patch is not completely black. It has a transparent effect and only darkens the original image. The original image can be recovered almost completely: In this case the recovery was pretty straightforward. I needed to check the range of grey levels of the patch and re-...


63

Ditto Ben N, but let me add a couple of points that are too long to fit as comments. I'd emphasize the distinction between layered and un-layered data formats. Drawing a black box over a section of a GIF, JPG, or PNG image destroys the previous contents. Drawing a black box over a section of a Photoshop, Corel Draw, or Paint Shop Pro native image does not ...


45

Normally, I'd just parrot the "nuke it from orbit and start from the beginning" line. However, information security is also about understanding your adversary, the practical risk, and the assets you're trying to protect. In this case, I think situation is a bit different; your spouse clearly just Googled for "free key logger" and downloaded the first one or ...


45

Change all your passwords! (no one had mentioned this) This is assuming that you're going to take an open approach to this problem rather than engage in counter-spying or image manipulation of your own. It's fairly basic advice, but do this on a computer you trust (this one cleaned or at work), and don't re-use any of your old passwords. Personally, I like ...


45

Usually the PNG format does not support multiple layers. So when you draw over something, whatever was there before is lost. However, the PNG format supports storage of an unlimited amount of metadata which is usually not displayed by image viewers. This feature is often used by image editors to add additional metadata to the image. One possible use-case is ...


38

If you are in a crowd and you wear a mask, but nobody else in the crowd does, then you tend to attract attention... If you want to remain anonymous, then you must use only tools which do not single you out as a potential miscreant, i.e. tools that everybody uses. A good example is when you pay in cash: this is a mostly traceless payment system, and yet ...


38

Because normal read operation on a disk presenting error (physical or logical) may cause data corruption, destruction and even writing to recover bad blocks. You have to keep in mind that even the read operation may lead to physical damage or data modification.


29

Yes, the text can be unmasked, either by simply zooming in or using any of the techniques - but not restricted to - pointed by pabouk and Peter answers. I have clearly asked for the correct/most secure way of producing photographic evidence. Completely remove any sensitive data from print-screens. Steps Press the PRT SCR button on your keyboard (...


24

It depends on how smart the thief is. We work with police to catch criminals based on their IP address on a regular basis. We've got a high success rate, but we can't catch them all. Usually, the IP address is enough to trace the connection back to the ISP (Internet Service Provider). Generally, ISPs will work with law enforcement in cased of known fraud ...


21

When blacking out sensitive information in Paint the original pixels are destroyed. But using Inkscape to black out part of a vector image does not destroy the pixels, but instead covers them. If someone removes the black cover they can see the pixels. The same applies to things like Foxit Reader (I almost sent a document with sensitive information which had ...


20

I believe the term you're looking for is "honeypot".


19

1: The ISP only knows the MAC addresses for the address of the hotel's router. It may store that, but who cares. The hotel could store mac addresses for connected devices, and many do for captive portal use, but that history is typically forgotten after only a couple of days. The only way to know is to ask the hotel. (they probably won't know how to access ...


19

The only reliable evidence of an internal person attacking your systems is if you catch them with their fingers on the keyboard. People often suspect insiders because they have spent an extraordinary amount of money building extremely sophisticated defenses, and they simply cannot imagine a hacker being able to navigate them. They have grandiose releasing ...


18

The SIM card must be plugged into a device for it to be functional in any way. It does not contain a power supply or an antenna. As such, it'd be impossible to track a SIM card on its own. However, once you plug it into a phone and power it on, the IMEI number of the phone and the SIM's serial number will be transmitted to the nearest cell tower(s).


18

Have you seen the Tor document on how a Tor Hidden Service works? Essentially, in the same way that it's hard to find the source of traffic from a Tor exit node, it's hard to find the server operating a Tor Hidden Service. Authorities can't shut down the server, because they can't find out where it is. The .onion TLD is not really a TLD (so there is no ...


16

See SSD (Flash Memory) security when data is encrypted in place and watch the discussion links on hard drives. On older drives, it was likely possible to recover overwritten data. The density of modern drives for the past 5+ (and the plus may be 10, 15, or more) years has been so high that a single pass of random data means whatever was there before is just ...


16

Like many others mentioned, there are trust issues here. thats needs sorting. the best way is a face to face discussion. an even better way to invite her is by typing out the invitation on your computer so that she sees your invitation and also comes to know of the keylogger in there. Now that you know your laptop is insecure, you should setup some admin ...


16

As a raster image program that does not use layers nor contain an undo history after saving, overwriting sensitive pixels in Paint irrevocably changes them in the saved image. More reasoning: Microsoft Paint is a proven simple piece of software with a long history and great popularity that works natively in simple raster image file formats. Serious flaws ...


15

DVD-R discs include the serial number of the drive used to burn them. There is a program called DVD Info Pro that is able to read that part of the disc and extract the drive's model and serial number. To do so, select "Read burn info from DVD-R/RW media". Commercially pressed discs don't seem to contain any such information. I was unable to find any ...


14

Disclaimer The approach I am about to describe might be unethical and perhaps even illegal. I am posting this for two main reasons: one I have no emotional attachment to your relationship; and two, because I like solving problems, the answer below is from a technical point of view: I am not really suggesting you do as I say below - the other answers that ...


14

I essentially agree - using Tor from within Harvard's own WiFi network was a big mistake. Note that in this case, the perpetrator did not have the nerve to stay silent in the face of police questioning. His confession is what made the case against him airtight. Had he "lawyered" up, the police would have: Evidence that he used Tor around the time the ...


14

Experts are experts. What an expert says stands in court as long as: He is an expert. The other party cannot provide another expert, who says that the first expert is wrong, and says it in a more convincingly expertish way. In practice, a email will be reputed to have been sent from a given PC if the context makes it a lot more plausible than any ...


13

This will depend entirely on what logging you have enabled. It it's easy after the event to tell you to log all file copies etc, but if you weren't logging it, you won't be able to retrieve that info.


13

The right way to "wipe out" data is to use encryption: never let unencrypted data ever hit the disk. If you do that, then destroying the decryption key is sufficient to destroy the data. The decryption key is small and in many case you can keep it in RAM only (e.g. you type it upon boot, as a "password", which really means "a key that a human remembers"); if ...


13

I would go for Kali Linux . This Linux distribution is made for pentesting and security analysis. It contains a great many analysis tools, right in your main menu. In general, I would use an Open Source OS for security-related work, because with Open Source there is public scrutiny that your tools themselves are not compromised.


13

Already a few good answers here, saying Paint is safe. (I have no reason to believe otherwise.) Just want to add that while blacking out a rectangle that fully covers the area and any surrounding areas (lists that information is part of etc) using a basic well studied image editing program should be fairly safe, just using any image editor might not be ...


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