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81 votes
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What is the attack scenario against which encrypted files provide protection?

File-level encryption can be useful in several cases, here's a few examples: Sending data over insecure channels. You mentioned TLS, and that's enough when you have it. But what if you aren't sure ...
reed's user avatar
  • 15.8k
69 votes
Accepted

Why would I ever use AES-256-CBC if AES-256-GCM is more secure?

CBC and GCM are quite different. Both are secure when used correctly, but CBC isn't as parallelizable and lacks built-in authentication. Due to this, CBC is only really practical for encrypting local ...
Therac's user avatar
  • 2,680
63 votes

Do Veracrypt encrypted volumes have any kind of brute force protection?

Any encryption is vulnerable to brute force attack, for example AES-256 has 2^256 keys, and given enough hardware we can “easily” brute force it. The problem is that there’s not enough silicon on ...
Andrew Morozko's user avatar
52 votes

Strongest file encryption available

The strongest possible way to encrypt data is to start with a threat model. What sort of adversary are you trying to protect your data from? What are they willing to do to get it? All reasonable ...
Cort Ammon's user avatar
  • 9,416
47 votes
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Not understanding why I should use public/private key encryption over password?

The two options are intended for different use cases. Option 1 is intended for your use case. It encrypts the file with a key derived from a password, so that only the person who knows the password (i....
nobody's user avatar
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37 votes
Accepted

Is there any reason I shouldn't make a GPG-encrypted file publicly-accessible?

There is always a risk that any given cipher will be broken at some point and data like this will become truly public. So yes there are some risks but it doesn't mean you aren't making a reasonable ...
Trey Blalock's user avatar
  • 14.2k
32 votes

Strongest file encryption available

If you want the strongest, I’d suggest a one-time pad to encrypt the file. If you want realistic, I suggest you rather expand on what your threat model is and take advice as to the actual level of ...
Gwyn Evans's user avatar
31 votes

Why would I ever use AES-256-CBC if AES-256-GCM is more secure?

Big nitpick: GCM = CBC + Authentication. Nope, GCM = CTR + Authentication. But in general you are right; CBC is an older mode that was invented back in the dark ages cryptographically speaking (...
Luis Casillas's user avatar
29 votes
Accepted

Downloading a file from a server with a secret: in text or binary?

There isn't really a difference. If you use proper TLS encryption, neither can be read by a man in the middle, and if the server properly authenticates requests, nobody who is not allowed to will be ...
tim's user avatar
  • 29.7k
24 votes
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Is it possible to read a text file inside a password-protected zip file without the password?

No. There are two ways of zip encryption, a classic one, which is weaker, and a newer one based on AES. In both cases the password is needed in order to decrypt the contents (i.e. it's not just UI, ...
Ángel's user avatar
  • 19k
22 votes

Do Veracrypt encrypted volumes have any kind of brute force protection?

Didn't veracrypt creators know about this issue? (Not having brute-force protection) As Andrew Morozko notes in his answer, they have addressed this – as far as it is possible – by using a ...
TripeHound's user avatar
  • 1,330
22 votes

Not understanding why I should use public/private key encryption over password?

There's one advantage of using public key cryptography over private key cryptography when you're encrypting file for yourself. When you use symmetric cryptography, you need to expose the password ...
Lie Ryan's user avatar
  • 31.5k
16 votes

Strongest file encryption available

I know nothing about cryptography. How do we encrypt a file in strongest (emphasis added) possible way such that we can access them some years later. I prefer that it should be fairly resistant from ...
hft's user avatar
  • 5,036
15 votes

Is it possible to use SSH agent for generic data encryption?

It is not possible to use the SSH Agent to asymmetrically decrypt data that was encrypted with the public key because the SSH Agent only exposes the ability to sign using the private key, not decrypt. ...
leighmcc's user avatar
  • 291
15 votes

How to prevent illegal file transfer or copying of video files from a PC?

As you state in the question, doing this in a foolproof way is technically impossible. For the video to be displayed on the screen it must somehow reside somewhere in the RAM on the computer, be ...
Anders's user avatar
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14 votes
Accepted

Are MySQL's database files encrypted?

Are MySQL database files that are stored on disk encrypted? No, they are not. You can (relatively) easily test this by moving .ibd or .myd files to a different system, where you can still read them....
tim's user avatar
  • 29.7k
14 votes

Keep encrypted files in sync on a cloud service, without having to upload an entire encrypted volume each time

this would mean, obviously, re-uploading the single volume every time even the smallest file in it changes; It is clear that this rules out, for different reasons, VeraCrypt or EFS. That's not true. ...
techraf's user avatar
  • 9,149
14 votes

Why would I ever use AES-256-CBC if AES-256-GCM is more secure?

CBC is older, which means more compatibility and just overall historical reasons. There are performance advantages, if you don't need GCM for authenticity. You often may want your own system for ...
Peter Harmann's user avatar
14 votes
Accepted

Does File-Based Encryption offer comparable security to Full-Disk Encryption on Android?

Full Disk Encryption (FDE) systems (like Truecrypt, BitLocker and FileVault) encrypt disks at the level of disk sectors. This is an all-or-nothing approach, since the encryption drivers won’t ...
Overmind's user avatar
  • 8,899
14 votes

What is the attack scenario against which encrypted files provide protection?

Full disk encryption provides no protection whatsoever against attacker with remote access while your machine is powered (as by definition FDE requires data to be decrypted on every access). So in ...
Matija Nalis's user avatar
  • 2,305
12 votes

How to prevent illegal file transfer or copying of video files from a PC?

Do not roll your own DRM scheme. The industry have tried and failed so many times that a homebrew solution will stand little chance. It would be better to "stand on the shoulders of giants" and use ...
billc.cn's user avatar
  • 3,946
12 votes

Downloading a file from a server with a secret: in text or binary?

No, If the type of file is specified then there is no added security at all. For example, unzipping a file is so trivial that it doesn't add any security. If you ask whether it's more secure to ...
Gudradain's user avatar
  • 7,021
12 votes

What is the attack scenario against which encrypted files provide protection?

The only point I can see is a low-skill attacker which has access to the machine with the encrypted file. Essentially if a friend / family member has access and does not accidentally see something....
yeah_well's user avatar
  • 3,804
11 votes

Is there any reason I shouldn't make a GPG-encrypted file publicly-accessible?

I think one of the biggest risks is that somebody is accidentally going to replace an encrypted file with its unencrypted version. Keeping the files in a private place protects against that. It's part ...
David Z's user avatar
  • 797
11 votes

Is it possible to read a text file inside a password-protected zip file without the password?

No, nowadays zip files are protected by AES. This will hide all of the plaintext in a way that you can only recover it when you have the key. The only other thing you can see is the size of the ...
Maarten Bodewes's user avatar
11 votes
Accepted

How long should zip encryption password be for it take 10 years to crack?

If you are using ZipCrypto for encryption, then any password length is insecure. You are using the ZipCrypto cipher, rather than the more secure AES. ZipCrypto is extremely weak, as it is based ...
forest's user avatar
  • 67k
10 votes
Accepted

Will prepending random data (of random length) result in more secure communication?

No, this won't provide any improvement for encryption with any decent cipher. If a cipher is so bad that a known-plaintext attack is capable of fatally breaking it, then the cipher is worthless. A ...
forest's user avatar
  • 67k
10 votes

How to quickly find out what the threat nature of a password protected archive is without getting infected?

I am wondering about how to find out the exact nature of the threat in a secure way Doing malware analysis yourself is pretty hard - malware is often designed so that it can't easily be reverse ...
ManfP's user avatar
  • 531
10 votes

Strongest file encryption available

This isn't a problem with an obvious solution. You need to plan in advance how you are going to handle and safely store your key material as well as your encrypted material. The strength and type of ...
Pedro's user avatar
  • 3,931
9 votes

How to recover a lost zip file password?

Just wanted to add another method using fcrackzip CLI tool. It's in most Linux distro repos such as Ubuntu & Fedora/CentOS. Using it is pretty straightforward: $ fcrackzip -b -c a1:$% -l 1-6 -u ...
slm's user avatar
  • 255

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