How are law enforcement agencies able to retrieve data off of a device or sim etc. that has been erased/deleted, yet we cannot retrieve our own lost data? Isn’t the point of erasing something to completely erase it…
In: Technology
When you tell a computer to delete something, it usually isn’t actually removing the data from the device, it’s just taking it out of the index (a big list of data you have on the device that lets the computer find the data), and opening up the space it was stored in to be overwritten by new data. So until something else overwrites it, it’s still there if you have the equipment and/or software to find it. And if it’s partially overwritten, sometimes you can recover enough pieces to see what it was and rebuild it.
It’s done this way since it takes less time and energy to just open up an area of storage than it is to actually remove the data. And 99% of the time, that’s all you need. But if you want to completely delete data, you can use special software that overwrites the deleted data with random 1s and 0s to make sure there’s nothing left there to recover.
But even then, sometimes small amounts of data can still be recovered, depending on the device and how the random junk data was written. For example, a magnetic hard drive stores data with a thin disc of metal encased in glass, divided into tons of tiny sections. Each section will be magnetically aligned one way or another, and this is used to represent 1s and 0s and store data. If some data is in the same place on the drive for a long time, the metal can kinda become set with that specific pattern of magnetic alignment, for lack of a better phrase. Then, when you overwrite it, some tiny bits of the metal will still have that old pattern. Not enough for it to mess up the data you wanted to store, but enough that somebody with specialized equipment can find some of the deleted data if they know what they’re doing.
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