I could probably look up some of these questions on Google, but I have found that a lot of times questions like these aren't directly answered, and with a little knowledge I can be very wrong. Besides that, discussion is always good because Google never says, "The question you really should be asking is..."
These are just questions that have nagged me off and on over the years. I am coming from a position of ignorance. I'm just a casual, occasional user who uses https and has a few times encrypted a few personal files when my computer had multiple people who could access it.
Oh, and I'm primarily talking about encrypting a file then decrypting it later, not the one-way stuff used in passwords.
Suppose I have a computer file without a file header identifying it. How can I tell if it is encrypted? Do encrypted files have headers saying, "this is XYZ encryption" or something similar? I guess the same goes for encrypted radio transmissions and paper files.
Once I know I have a file that is encrypted with XYZ, and I have the code to decrypt it, I just need a key of some sort, right? So I run the decryption with a key. How do I know if it worked? Does the decryption result in something in the decrypted version that says, "Success!" or do I have to look at the results and see if it now makes sense, like seeing an Excel header?
If it's the latter, how do you know when a file is encrypted twice by two different algorithms?
I hear about how long it takes to guess a key with brute force. If it's a file, can't I keep cutting down on this time by using multiple computers on multiple copies of the file? I guess I'm asking what "10 years" really means because it seems like 20 computers could make it six months.
With all the talk of bad actors, how feasible is it for the bad guys to hire some guru to write a really good sophisticated encryption algorithm and keep it quiet? When the good guys get a file, they can't find any known decryption algorithm to use for an attack.
Does this happen now? How do the good guys get around it? I'm guessing they would have to find the compiled code for encryption/decryption in addition to the files, then decrypt that (I figure anyone going to that much trouble would only use it on encrypted devices) and reverse-engineer the executable. Is that how it would work?
That sounds feasible if, for example, people are exchanging encrypted files via e-mail. You'd expect to find at the code nearby. But that wouldn't be the case with radio transmissions that get intercepted.
Without the actual algorithm, how in the heck would you go about reverse engineering it with no key and one file? Could you even do that these days?
Thanks for looking at all these newbie questions, and I apologize in advance if some are ridiculously ignorant.
These are just questions that have nagged me off and on over the years. I am coming from a position of ignorance. I'm just a casual, occasional user who uses https and has a few times encrypted a few personal files when my computer had multiple people who could access it.
Oh, and I'm primarily talking about encrypting a file then decrypting it later, not the one-way stuff used in passwords.
Suppose I have a computer file without a file header identifying it. How can I tell if it is encrypted? Do encrypted files have headers saying, "this is XYZ encryption" or something similar? I guess the same goes for encrypted radio transmissions and paper files.
Once I know I have a file that is encrypted with XYZ, and I have the code to decrypt it, I just need a key of some sort, right? So I run the decryption with a key. How do I know if it worked? Does the decryption result in something in the decrypted version that says, "Success!" or do I have to look at the results and see if it now makes sense, like seeing an Excel header?
If it's the latter, how do you know when a file is encrypted twice by two different algorithms?
I hear about how long it takes to guess a key with brute force. If it's a file, can't I keep cutting down on this time by using multiple computers on multiple copies of the file? I guess I'm asking what "10 years" really means because it seems like 20 computers could make it six months.
With all the talk of bad actors, how feasible is it for the bad guys to hire some guru to write a really good sophisticated encryption algorithm and keep it quiet? When the good guys get a file, they can't find any known decryption algorithm to use for an attack.
Does this happen now? How do the good guys get around it? I'm guessing they would have to find the compiled code for encryption/decryption in addition to the files, then decrypt that (I figure anyone going to that much trouble would only use it on encrypted devices) and reverse-engineer the executable. Is that how it would work?
That sounds feasible if, for example, people are exchanging encrypted files via e-mail. You'd expect to find at the code nearby. But that wouldn't be the case with radio transmissions that get intercepted.
Without the actual algorithm, how in the heck would you go about reverse engineering it with no key and one file? Could you even do that these days?
Thanks for looking at all these newbie questions, and I apologize in advance if some are ridiculously ignorant.
via International Skeptics Forum http://ift.tt/1RDpgIb
Aucun commentaire:
Enregistrer un commentaire