Questions tagged [file-encryption]

The process of encrypting individual files on a storage medium and permitting access to the encrypted data only after proper authentication is provided.

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Technology that can survive a "Rubber-Hose attack"

In the documentary film Citizenfour, Edward Snowden says about documents: I'm comfortable in my technical ability to protect [documents]. I mean you could literally shoot me or torture me and I ...
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84 votes
6 answers
191k views

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

I guess the gist of my question is: Are there cases in which CBC is better than GCM? The reason I'm asking is that from reading this post by Matthew Green, and this question on cryptography stack ...
The Quantum Physicist's user avatar
73 votes
3 answers
39k views

What security scheme is used by PDF password encryption, and why is it so weak?

Many PDFs are distributed as encrypted PDFs to lock out some of their functionality (eg printing, writing, copying). However, PDF cracking software is available online, which usually cracks the PDF ...
March Ho's user avatar
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56 votes
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How to recover a lost zip file password?

I have some files I was given by my teacher at University, I could chase him up, but I may as well try getting blood from a stone, his response rate isn't great and I completed my degree a year ago! ...
bluekeys's user avatar
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46 votes
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Why would an encrypted file be ~35% larger than an unencrypted one?

According to the ownCloud documentation, if you enable encryption, file sizes can be ~35% larger than their unencrypted forms. From my understanding of encryption, the file sizes should be more-or-...
warren's user avatar
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42 votes
5 answers
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How secure is a Windows password protected zip file?

I need to send some sensitive information to a client. I thought I would email a password protected zip file I created using Windows XP and then call them with the password. Presuming I pick a good ...
Dave Aaron Smith's user avatar
40 votes
8 answers
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What is the attack scenario against which encrypted files provide protection?

There are a couple of files / tools which provide file-level encryption. I guess PDF and ZIP are probably the most commonly known ones. I wonder what scenario they actually help with or if it just is ...
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Does password protecting an archived file actually encrypt it?

For example if I use WinRAR to encrypt a file and put a password on the archive how secure is it? I keep a personal journal and am thinking of doing this, or is there a better way? It's just one huge ....
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How secure is NTFS encryption?

How secure is the data in a encrypted NTFS folder on Windows (XP, 7)? (The encryption option under file|folder -> properties -> advanced -> encrypt.) If the user uses a decent password, can this ...
Martin's user avatar
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31 votes
6 answers
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Do spaces in a passphrase really add any more security/entropy?

I often see passphrase suggestions written as a sentence, with spaces. In that format are they more susceptible to a dictionary attack because each word is on it's own as opposed to a large unbroken ...
v15's user avatar
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30 votes
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Is there any reason I shouldn't make a GPG-encrypted file publicly-accessible?

I'm working on a project where we need to keep a few specific files easily accessible, but encrypted. My idea for accomplishing this is to have the files available in the project's public website, ...
Chris's user avatar
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27 votes
3 answers
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Is EncFS secure for encrypting Dropbox?

I've encrypted my Dropbox folder with EncFS according to a few tutorials I found on the web, advocating this approach. But I've found the following critical statement concerning EncFS's security in ...
steffres's user avatar
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2 answers
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Does File-Based Encryption offer comparable security to Full-Disk Encryption on Android?

Between version 4.4 and 9, Android supported Full-Disk Encryption (FDE). On Android 7, a new system called File-Based Encryption (FBE) was introduced, and was subsequently made mandatory on Android 10....
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24 votes
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Brute Forcing Password to a Truecrypt-encrypted file with Partial Knowledge

A while back, I encrypted a few files with Truecrypt, and stored the password in my head. Now I need to access it again, the password isn't working. I'm sure most of it is right, but I'm off by one or ...
Robyn's user avatar
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6 answers
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Strongest file encryption available

I know nothing about cryptography. How does one encrypt a file in the strongest possible way, such that it can be accessed some years later? I prefer that it should be fairly resistant from brute ...
dave09963's user avatar
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Do Veracrypt encrypted volumes have any kind of brute force protection?

I have a 10mb encrypted volume which I made with Veracrypt and was planning to upload it to the internet. I have a pretty strong password but was worried about its protection against brute force ...
Eka's user avatar
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Would it be plausible to write your own anti-crypto-ransomware tool? [closed]

Question After reading about how basic ransomware targets and encrypts your files. I was wondering if it would be plausible to write your own script to try and detect such activities? Initial ...
Chris's user avatar
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9 answers
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Keep encrypted files in sync on a cloud service, without having to upload an entire encrypted volume each time

Situation: User has several folders worth of GBs which they want to keep in sync on a cloud service (for example Mega or Dropbox) in an encrypted form; User does not want to sync a single encrypted ...
nonhocapito's user avatar
20 votes
3 answers
7k views

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

My knowledge about these topics is very elementary, please "school me" if I said something completely wrong, it would surely help me understand these things better. Now, to my issue. Now ...
RenatoRenatoRenato's user avatar
20 votes
8 answers
13k views

Are there any "real world" implementations of secret-sharing encryption schemes?

Imagine something like TrueCrypt where user A can decrypt his files, or any 3 of the 10 directors in his organization can decrypt user A's files. As I understand it this is similar to the way the ...
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What are you doing when you move your mouse randomly during a truecrypt volume creation?

Is that called a 'round' every time you move your mouse when creating a new volume? I'm talking about the screen with the random numbers during the volume creation process. What is the purpose of ...
v15's user avatar
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18 votes
5 answers
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Encrypting files in a windows environment

We have certain client data which must be encrypted at all times. The part we have been struggling with is encrypting files on network shares. Currently we have network folders encrypted using PGP ...
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17 votes
3 answers
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Is it possible to use SSH agent for generic data encryption?

Is it possible to use running SSH agent to decrypt some data (supplied as a string or read from file)?
anatoly techtonik's user avatar
16 votes
5 answers
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VeraCrypt/TruCrypt - I can't understand why you'd want to create a "hidden" volume...?

I can't think of a reason as to why you'd want to create a hidden volume in VeraCrypt. It says because "you may be asked to hand the information," but why would I need to hand it over? Nobody has any ...
Jack's user avatar
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16 votes
4 answers
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What's the standard way to encrypt a file with a public key in Java?

I'm writing a client app in Java that sends encrypted data back to the server. All clients have my RSA public key. Is there a standard way to encrypt a given file with it to send it back to the server?...
Jean-Philippe Pellet's user avatar
16 votes
2 answers
15k views

Simple way to encrypt files on Linux and decrypt on Windows?

We are in need of an encryption process for backups of very valuable data. This data will be stored on a distributed filesystem, so even with permissions set right, it's not out of reach that this ...
josen's user avatar
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14 votes
5 answers
13k views

How can I decrypt data with Java, without hard-coding the key?

I hope this is not a chicken-egg problem or reinventing the wheel but here goes. I have a Java application that needs to access a password protected file (actually during the application startup). The ...
Jim's user avatar
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14 votes
4 answers
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Encrypting data by parts vs encrypting the whole data

Suppose I have a file with records, and I have two options to encrypt it: encrypt the file as a whole encrypt each record separately and store them together. Which way is generally preferable and ...
Andrew T's user avatar
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14 votes
2 answers
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Is ccrypt 'AES 256' file encryption fundamentally flawed

The unix/linux utility ccrypt claims to be a more secure replacement for the old unix crypt. However it seems to me that it has a fundamental flaw. When you encrypt a file using ccrypt it uses the ...
Chris Green's user avatar
14 votes
1 answer
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Forgot password to 7-Zip archive

I think I already know the answer to this question, but I thought I'd ask the experts anyway. A few months back, I created a password-protected 7-Zip archive which housed the source code of a simple ...
Matthew's user avatar
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14 votes
3 answers
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How long should zip encryption password be for it take 10 years to crack?

I am using zip 3.0.0 on macOS High Sierra and Ubuntu. Here is my zip version on macOS: $ zip --version | head Copyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license. This is ...
Lone Learner's user avatar
13 votes
5 answers
37k views

Whats the point in having software's like Veracrypt, which end of the day needs password to decrypt?

There are encryption softwares like Veracrypt which encrypt data and the only way to open encrypted file is via password, but a simple compressing softwares like RAR also provide password protection. ...
Red Aura's user avatar
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13 votes
5 answers
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Good file encryption tools [closed]

Could you please help me find a good file encryption tool? The target OS is Linux, but tools for Windows are welcome, too. FOSS tools are preferred. The tool must be reliable both for the recovery of ...
ML--'s user avatar
  • 239
13 votes
1 answer
2k views

Secure backup encryption with OpenSSL

I know, the general advice is "keep your hands off crypto stuff". And the standard way to encrypt backup data securely would be using GnuPG. However, for a rather academic exercise, I would like to ...
Daemotron's user avatar
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12 votes
1 answer
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Why is GPG file encryption so much slower than other AES implementations?

Correct me if I'm wrong: When encrypting a file, GPG creates a one-off AES encryption key and encrypts that key using RSA. This is supposedly to take advantage of AES's superior performance when ...
Jon Staryuk's user avatar
12 votes
5 answers
1k views

Security of using passwords or even passphrases to encrypt files

Is it ever appropriate to use real-world passwords to encrypt files to be sent via unsecure means. By real world, I mean a password that is memorable and memorisable by a mere person? I am implying ...
Andrew Russell's user avatar
12 votes
2 answers
9k views

How to encrypt data on the server?

I have some data on the server (running Linux) which needs to be encrypted (company policy). This data is being served by an application running on this machine. Now I consider a few possibilities: 1)...
Janek's user avatar
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12 votes
5 answers
26k views

What does Windows's built-in encryption do, if I can seemingly always read my encrypted files?

I'm playing around with certificates and encryption on a Windows system, but either it isn't working or I don't know how it should works. When I encrypt a file its name changes to green. But then, I ...
user avatar
12 votes
2 answers
9k views

After How Much Data Encryption (AES-256) we should change key?

Considering AES-256 encryption, what is the maximum amount of data should be encrypted with one key? Does Block cipher modes/IV/counters also governs the limit? If say the maximum amount is 50GB, ...
Deepesh M's user avatar
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12 votes
6 answers
849 views

How to protect against adversaries snatching booted laptops to defeat full disk encryption?

I read an article describing how FBI agents snatched Ross Ulbricht's laptop while it was running to defeat full-disk encryption: Two plainclothes FBI agents, one male and one female, walked up ...
James Mishra's user avatar
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11 votes
4 answers
16k views

Are MySQL's database files encrypted?

I'm trying to securely store user credentials in a MySQL database which is hosted on a different server than the application (the communication between the two is secure). I have initially assumed ...
leopik's user avatar
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11 votes
12 answers
14k views

How can I share files with other individuals using the cloud in a secure way?

I would like to use a dropbox because it is easy and convenient. But I want to encrypt the files with the public key of the intended recipient, so he will be the only one who can access the data in ...
Hotze de Jong's user avatar
11 votes
5 answers
17k views

How secure are the password files used by Password Safe and Password Gorilla?

Password Safe and Password Gorilla are both programs to manage passwords. Both store a list of user passwords in a file, which is encrypted using a master password. They use the same file format, so ...
Nathan Long's user avatar
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11 votes
3 answers
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Linux Plausibly Deniable File System

Is there any way to encrypt a Linux filesystem in such a way to maintain plausible deniability? E.g. "Hidden OS support," the way TrueCrypt and Veracrypt work, they only support Windows OS due to low ...
grepNstepN's user avatar
11 votes
2 answers
10k views

What trust level should I give keys I need for encryption?

As I'm encrypting server backups, I typically install my public GPG key from a keyserver into me server's keyring: gpg --search-keys 6569758F I import the key into my keyring. I then attempt to ...
Naftuli Kay's user avatar
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11 votes
1 answer
784 views

Is it possible to decrypt half of a TrueCrypt file container if the other half of the data is missing?

Let's say we have half of a TrueCrypt file container (e.g. download was interrupted). If we know the password, is it possible to open it and get half of the data? The original container has 10 files, ...
Alex's user avatar
  • 113
10 votes
4 answers
7k views

Is Changing a File Type and Name an Effective Security Solution?

Is renaming folders & files and changing file types an effective solution for file security of a PC? I am an application programmer and have an extensive background in it. I have written a ...
Cody Brown's user avatar
10 votes
4 answers
3k views

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

I have recently received an e-mail from an existing support group e-mail box with the following characteristics: written in the language used in company's HQ (different from English which is the ...
Alexei's user avatar
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10 votes
3 answers
516 views

How can I allow access to encrypted data if only 2 out of 3 users provide a secret?

I want to encrypt data, but make sure that no single user can decrypt the data. Further, it is important not to require ALL users to be present to decrypt. This will allow for some flexibility and ...
Karl Ivar Dahl's user avatar
10 votes
2 answers
4k views

Microsoft Office 2013 File Encryption

To what extent can the native file encryption provided by Microsoft Office 2013 (Word, Powerpoint, Excel, etc.) be relied upon to maintain the confidentiality of documents, especially within the ...
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