Questions tagged [encryption]

Encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge.

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132 votes
7 answers
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SSH: The authenticity of host <host> can't be established

What does this message mean? Is this a potential problem? Is the channel not secure? Or is this simply a default message that is always displayed when connecting to a new server? I am used to ...
Steven Lu's user avatar
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129 votes
25 answers
26k views

How to find and remove "spicy" media files from my PC [closed]

I have an embarrassing problem: during my younger and wilder days, I used to download a certain type of movie clips and pictures. The combination of youthful foolishness and a couple of beers ...
Scott's user avatar
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116 votes
6 answers
88k views

How can I use encryption with Gmail?

I'm currently reading Cory Doctorow's novel Little Brother which includes a part about encrypted messaging, and even wrapping messages first in my private key and then your public key. I'd like to ...
Torben Gundtofte-Bruun's user avatar
109 votes
10 answers
400k views

How to access a BitLocker-encrypted drive in Linux?

I have a laptop running Windows 7 Ultimate. I have encrypted my drives using BitLocker. Now I have also installed Lubuntu along with Windows. But my encrypted drives are not visible in Linux. How ...
Suyash Mohan's user avatar
  • 1,295
90 votes
7 answers
42k views

Compress and then encrypt, or vice-versa?

I am writing a VPN system which encrypts (AES256) its traffic across the net (Why write my own when there are 1,000,001 others already out there? Well, mine is a special one for a specific task that ...
Majenko's user avatar
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87 votes
14 answers
175k views

Which TrueCrypt Algorithm is the safest?

If performance is of no concern, which TrueCrypt algorithm is the safest to use? AES Serpent Triple DES Twofish AES-Twofish AES-Twofish-Serpent Serpent-AES Serpent-Twofish-AES Twofish-Serpent
Amir Rezaei's user avatar
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82 votes
5 answers
71k views

How to use ssh-rsa public key to encrypt a text?

So, the scenario is: Given I'm Bob, I want to encrypt some message for Alice. The only public key I have is her ssh-rsa id_rsa.pub like this: ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAyb+...
sikachu's user avatar
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72 votes
4 answers
45k views

What are the correct permissions for the .gnupg enclosing folder? gpg: WARNING: unsafe enclosing directory permissions on configuration file

I don't want to just chmod and run until I get the right answer, nor do I want to run GnuPG as root. The easy fix would be to just set it so that only my user can read it, but I don't think that's the ...
Nathan Basanese's user avatar
70 votes
1 answer
53k views

How do I symmetrically encrypt a file using gpg?

I'm trying to symmetrically encrypt a file using gpg. $ gpg --encrypt --symmetric $MYFILE I enter and re-enter a passphrase, then gpg tells me You did not specify a user ID. (you may use "-r") ...
dave4420's user avatar
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70 votes
8 answers
32k views

Is TrueCrypt truly safe?

I have been using TrueCrypt for a long time now. However, someone pointed me to a link that described the problems with the license. IANAL and so it really didn't make much sense to me; however, I ...
user avatar
67 votes
3 answers
89k views

Simple built-in way to encrypt and decrypt a file on a Mac via command-line?

Are there any built in command-line tools that I can encrypt and decrypt a text file (and provide it some sort of password).
codecompleting's user avatar
63 votes
6 answers
48k views

What is better for GPG keys - RSA or DSA?

ssh-keygen defaults to creating RSA keys, but gpg --gen-key prefers DSA/ElGamal. Which one - RSA or DSA - is better for GPG?
u1686_grawity's user avatar
61 votes
4 answers
45k views

Does full-disk encryption on SSD drive reduce its lifetime?

I would assume that a full-disk encryption deployment would introduce additional writes each time the computer is booted up and shut down. Given that solid state disks are considered to have a lower ...
Bill's user avatar
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59 votes
5 answers
33k views

Setting up an encrypted git-repository

Situation Hi, I would like to save data with git, encrypted (on some platform like bitbucket or github). Therefore the question: Question I am looking for different hassle-free ways on: How to set ...
BadAtLaTeX's user avatar
57 votes
8 answers
63k views

How to do Rsync-like encrypted backup?

I want to save a backup of my data on a remote server, but never want the backup server to see the data unencrypted. Editing a single file and backing up should not result in everything being ...
user avatar
57 votes
1 answer
7k views

Short, easy to understand explanation of GPG/PGP for nontechnical people?

Does anyone have a link to a good, but short (1-2 paragraphs) explanation of the benefits of using GPG/PGP signing and encryption for Email focused at non-technical readers? That is, why would someone ...
jtimberman's user avatar
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53 votes
3 answers
38k views

How secure are password-protected zip files?

In modern zip utilities like 7zip, you can specify a password when creating a .ZIP file. But, how secure is this? What encryption algorithm(s) are used to secure password-protected zip files?
Justin Ethier's user avatar
49 votes
8 answers
12k views

How to mitigate any privacy-related risks associated with taking your laptop for repair? [duplicate]

Either my fan or my battery on my refurbished laptop is malfunctioning and it frequently overheats and shuts itself down. I wasn't able to determine the culprit and thought it best to show my laptop ...
user51309's user avatar
  • 583
49 votes
2 answers
7k views

Does changing the encryption password imply rewriting all the data?

Let's say I have 1 TB of data on a partition encrypted with BitLocker, TrueCrypt or VeraCrypt. Does changing the encryption password imply rewriting all the data (i.e., will it take hours/days)?
Basj's user avatar
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49 votes
2 answers
36k views

Best encryption and signing algorithm for GnuPG: RSA/RSA or DSA/Elgamal? [closed]

I have found this relatively old question about whether RSA or DSA is the preferred algorithm for signing and encrypting with GnuPG. When using gpg --gen-key, the two relevant choices are either "RSA ...
The-Q's user avatar
  • 675
49 votes
11 answers
51k views

Speed of TrueCrypt whole disk encryption

I'm getting a new development laptop soon, and I'm thinking of using TrueCrypt to encrypt the whole disk. What kind of performance drop can I expect? 10%? 30%? More? Also, assuming the workload has ...
Gareth's user avatar
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45 votes
1 answer
52k views

How do I fix "WARNING: message was not integrity protected" when using GPG symmetrical encryption?

I've encrypted a file using symmetric encryption like this: gpg --symmetric myfile which results in a file myfile.gpg. Alright. Now let's decrypt the file again: gpg -o myfile --decrypt myfile.gpg ...
gertvdijk's user avatar
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44 votes
3 answers
150k views

How to set password on already existing winrar archive and encrypt it also?

Not when creating new archive, but on existing archive. I would also like to know how to do that in other archiver.
Boris_yo's user avatar
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43 votes
8 answers
72k views

How to list encrypted files in Windows 7?

I somehow encrypted some files without meaning to, and because of it I can't backup my user folder to Mozy. Is there a way to remove the encryption from all the files or at least find out which one ...
holiveira's user avatar
  • 1,341
43 votes
2 answers
155k views

is there a way to stop mac osx disk encryption in progress?

I chose a 1T external drive for time machine and checked the "encrypt backups" option. I thought it will only encrypt the backups, but as it seems it is now encrypting the whole drive which has quite ...
Vitaly Kushner's user avatar
43 votes
3 answers
122k views

How to specify private key when decrypting a file using GnuPG?

I am trying to decrypt a file with GnuPG, but when using the command below: gpg --decrypt filename.gpg I get the following message: gpg: encrypted with RSA key, ID 3662FD5E gpg: decryption failed: ...
Crista23's user avatar
  • 533
41 votes
18 answers
14k views

Can I encrypt data in a way that it can be read normally but can't be copied or edited? [closed]

I want to share my 500 GB hard drive with a friend but I want to encrypt it in a way that all data can be read normally but cannot be copied or edited in any way. Is that possible?
41 votes
17 answers
50k views

How can clients easily and securely send me passwords? [closed]

I often need to get passwords from clients for FTP, SSH, MySQL, Authorize.net, etc. What's an easy way for them to send me passwords securely? Maybe even without them needing a login/password? ...
41 votes
1 answer
9k views

What does BitLocker actually encrypt and when?

I need full disk encryption for business laptop computers running a current version of Windows 10 Pro. The computers have an NVMe SSD drive from Samsung and an Intel Core i5-8000 CPU. From some web ...
ygoe's user avatar
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39 votes
2 answers
47k views

Mount encrypted HFS in ubuntu

I try to mount an encrypted HFS+ partition in Ubuntu. An older post described quite good how to do it, but lacks the information how to use encrypted partitions. What I found so far is: # install ...
pagid's user avatar
  • 493
38 votes
9 answers
60k views

How to encrypt a file or directory in Linux?

What's the most popular command to do such things as encrypting a file or directory in terminal in Linux?
user avatar
37 votes
5 answers
34k views

How does SSH encryption work?

I've read about generating 2 keys (private and public) on client host and copying the public key to the server host. As I understand it, (correct me if i'm wrong): The server encrypts data with the ...
DrStrangeLove's user avatar
36 votes
3 answers
8k views

Can Google Employees See My Passwords Saved in Google Chrome?

I understand that we are really tempted to save our passwords in Google Chrome. The likely benefit is two fold, You don't need to (memorize and) input those long and cryptic passwords. These are ...
Masroor's user avatar
  • 1,267
36 votes
9 answers
2k views

Password Cracking Windows Accounts

At work we have laptops with encrypted harddrives. Most developers here (on occasion I have been guilty of it too) leave their laptops in hibernate mode when they take them home at night. Obviously, ...
kemiller2002's user avatar
34 votes
6 answers
9k views

What can I do if someone tampers with my SSH public key?

I understand private keys being compromised is a huge risk; however, what about public keys. What if they are tampered with? If someone were to access my public key associated with the private key I ...
Kev's user avatar
  • 341
34 votes
5 answers
71k views

How does Google Chrome store passwords?

Are they encrypted in disk? How? Are they safe, for example, in the event of someone booting from a Live CD and mounting the hard disk? How is the encryption key generated? Is it different in ...
Óscar's user avatar
  • 341
33 votes
5 answers
108k views

How can I access volumes encrypted with LUKS/dm-crypt from Windows?

The answer to this question used to be FreeOTFE (https://en.wikipedia.org/wiki/FreeOTFE); sadly, the project has not been updated for three years and its website (http://www.freeotfe.org) is no longer ...
Mark Raymond's user avatar
31 votes
10 answers
47k views

BitLocker asking for protection code after Ubuntu installation

I have just installed Ubuntu side-by-side to a Windows 10 partition shipped on a new laptop. Meaning, the laptop shipped with Windows 10, and I installed Ubuntu alongside the Windows partition using ...
matanox's user avatar
  • 438
31 votes
4 answers
29k views

Encrypted WiFi with no password?

Is there any standard that allows a WiFi connection to be encrypted, but not require a password? i know that (old, weak) WEP, and newer WPA/WPA2 require a password (i.e. shared secret). Meanwhile my ...
Ian Boyd's user avatar
  • 22k
30 votes
10 answers
20k views

Determining if a hard disk has been removed and data copied from it?

Is there a method or a tool that can detect if someone has separated my hard disk from my computer, copied data from it, and returned it back? I want to be sure that no one has done this without my ...
Anyname Donotcare's user avatar
30 votes
4 answers
67k views

How can I encrypt a string in the shell?

Can I encrypt a message (string) using a public key at the command prompt? Also, how can I decrypt the result afterwards?
user avatar
30 votes
4 answers
15k views

Is it safe to store (encrypted) passwords on GitHub?

I am using pass to handle all my passwords. They are encrypted using GPG with a 4096 bits key, using the SHA256 algorithm. I am using a different password for every login in my password store. One of ...
Nicolas Mattia's user avatar
29 votes
1 answer
15k views

How does S/MIME differ from PGP/GPG, for the purpose of signing and/or encrypting email?

In addition to the titular question, are the two technologies compatible? If so, under what circumstances? What are the relative benefits of the two technologies?
user avatar
29 votes
4 answers
21k views

How resilient are VeraCrypt and LUKS encrypted volumes against data corruption?

The question has been partly answered, but that's still not what I'm exactly looking for. See for Update 1 down bere I'm planning to encrypt some filesystems with VeraCrypt and LUKS, but my fears are ...
X.LINK's user avatar
  • 2,370
28 votes
10 answers
3k views

Encrypted HDD 100% safe?

I guess am a bit of a paranoid ha... anyway i encrypted my HDD with truecrypt using all printable ASCII characters and the password is 64 characters long. It is quite random, certainly no dictionary ...
paranoiaISgood's user avatar
26 votes
4 answers
80k views

What does the encryption setting of uTorrent do?

I'm having trouble finding precise information about the encryption setting of uTorrent. From what I understand, it's used to hide the torrent traffic from ISPs so that they cannot make the difference ...
laurent's user avatar
  • 6,079
26 votes
1 answer
15k views

How to delete a subkey on Linux in GnuPG?

I would like to delete an OpenPGP subkey of mine on Linux (L)Ubuntu 16.04 in GnuPG. It's a kind of "blank" useless key (see below key 33333333). I have not uploaded it to key servers, so I think it's ...
aldaron's user avatar
  • 503
26 votes
4 answers
26k views

How to mount an encrypted ext3 filesystem under OS X?

I know how to mount an ext3 filesystem in OS X with MacFUSE and fuse-ext2. But how can I mount an encrypted ext3 volume? I have Mac OS X 10.6 "Snow Leopard" running.
viam0Zah's user avatar
  • 2,038
25 votes
5 answers
113k views

Windows 10 Password Error with Samba Share

I am trying to connect to a samba share with Windows 10 Pro (Version 1511, Build 10586.589) using the command net use L: \\myserver\myshare /u:myuser mypassword. I get the error: System error 86 - ...
roms's user avatar
  • 560
25 votes
2 answers
21k views

Is zip's encryption really bad?

The standard advice for many years regarding compression and encryption has been that the encryption strength of zip is bad. Is this really the case in this day and age? I read this article about ...
Nifle's user avatar
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