GNU Privacy Guard (GnuPG or GPG) is an open source implementation of PGP, a file encryption and signature tool widely used for emails

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Extremely slow GnuPG 2.x Performance

I have an curious problem with my script. The script runs very fast ,when i use GnuPG 1.x. With GnuPG 2.x it runs very slow at encryption/decryption, and i have no idea why. Versions: GnuPG 1.4.20-6 ...
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Is storing passwords encrypted with GnuPGP on an anonymous FTP server safe?

I would like some advice on a method of storing passwords to a database on my anonymous FTP server. Basically I have login details for a few trusted users to a database server stored in a text file ...
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Does it matter what version of GnuPG I use to create revocation certificates?

Today I am about to create a bunch of revocation certificates for all of my emails. Why? Because it already happened to me in the past, that I lost my private key, or my computer was compromised. It ...
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Why does the revocation sent to the OpenPGP keyservers not show up?

I have created a new OpenPGP key pair. So I wish to revoke the former I used. Here's what I managed to do so far: This way I found that email's ID = 3C76732B gpg --search ...
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17 views

What is the Purpose of placeholders (e.g. %k, %f) in some GnuPG options?

In some GnuPG options (--cert-notation, --sig-notation, --photo-viewer and others) there can be used certain placeholders (for instance %k, %f etc.). What is the purpose of using that placeholders? ...
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What is the purpose and meaning of the --sig-notation and --cert-notation options in GnuPG?

What is the purpose of the --sig-notation and --cert-notation options in GnuPG? What are the intended use cases? In the first part the a @ character is used, so I guess the options are for providing ...
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Why won't gnupg be fooled by my pseudoterminal trick? [migrated]

Gnupg requires many of its inputs to come literally from a terminal instead of just stdin. I sometimes can get around that with: pty-run: #!/bin/bash printf -v cmd '%q ' "$@" exec script --quiet ...
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Uids in GnuPG — 3 fields or 1

gpg2.1 allows me to do gpg2 --quick-adduid old_id new_id. There's no options to specify realname, email, and comment separately like in the interactive adduid. Also, in listings, the three fields ...
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19 views

How to import primary secret key from backup into GnuPG?

I've seen "Re-import secret primary key in GnuPG" which is pretty much the issue I'm seeing, but I haven't had any luck with GnuPG 1.4.20 (from GPGTools) or GnuPG 2.1. Even if I delete my entire ...
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Restore GPG key after exported to a smartcard

After exporting my private key, I moved my private key on a smart card using keytocard. This worked fine, and I could sign and use GnuPG as expected. Now I would like to go back to have the private ...
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127 views

Is the RSA private key useless without the password?

I notice whenever I generate a new gpg key (using pgp) I always have to assign a password to it, which makes perfect sense. But if I'm not mistaken, gpg is based on prime numbers. How is this ...
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Spam protection for public GPG keys?

Public keys published to a server almost always contain emails. Is there any sort of protection against bot harvesters that will use that email for spam?
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Revoking signing keys: do they still work afterwards?

Scenario: I have multiple signing subkeys, each for every portable device (i.e laptop). None of them have private master key (it is deleted following the tips in Alex Cabal's post. One of the devices ...
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31 views

PGP/GPG: Do I need more encrypton subkeys?

As far as I know after reading several tutorials, it's reasonable to create one subkey for signing per each device I use, especially one that can be stolen, like laptop. However, having multiple ...
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How does GnuPG encrypt secret keys?

When creating a secret key with GnuPG, you are asked for a password to protect it. Which encryption algorithm is used to achieve this? The handbook only says that a symmetric encryption algorithm is ...
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34 views

Would saving GPG and SSH keys as another user improve security?

Since e.g. SSH keys under Linux are owned by the user who created them, any applications running as the user, e.g. a web browser, should be able to read them from the ~/.ssh folder. Say that there is ...
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Is there any benefit to encrypting messages with PGP that will be trasmitted over SSL to a REST server?

Would there be any benefit at all to encrypting a message using PGP before sending it to a REST server over SSL, or is this completely redundant and a waste of processing time? For example, could a ...
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gpg 2.0 command line option to create UTF-8 data

With echo text | gpg2 --sign --textmode -a I can create messages with a one pass signature containing a Literal Data packet in TEXT ('t') format. If I skip the --textmode option it will generate ...
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Why does my private OpenPGP key look different between devices?

Something I noticed, when I use gpg --export-secret-keys -a on different computers: My private key looks different, even though they are the same key pair. Is that normal or does this indicate ...
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Does Thunderbird Enigmail plugin decrypt attached files?

From my research I have found out that you can easily send encrypted messages to one another using Enigmail. If first I encrypted a file,then attached it to an email, sending it through Enigmail to a ...
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How to decrypt a file encrypted under multiple public keys GPG

According to https://www.gnupg.org/gph/en/manual/x110.html To decrypt a message the option --decrypt is used. You need the private key to which the message was encrypted. Similar to the ...
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GnuPG does not verify signature while decrypting

I have signed file 1.txt, result file is 1.txt.asc. I changed content in file 1.txt.asc (signed content, not signature). Then I verify signature in 1.txt.asc and I get information that signature is ...
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How to get GnuPG fingerpints only for specified key name, not for substring matches?

I have few GnuPG keys: test, test2, some test. When I invoke gpg --fingerprint test, fingerprints of all keys are listed. When I run gpg --fingerprint test2, only test2 key fingerprint is printed. How ...
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Am I weakening symmetric OpenPGP encryption by deploying a custom pre-derivation?

I often use GnuPG to encrypt files with a passphrase. I'm very paranoid, and afraid that the key derivation used by GnuPG isn't slow enough. For this reason, I've decided to do my own key derivation ...
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Specifying my key name while encrypting file to some receiver using GnuPG

I would like to make sure of one thing. When I am encrypting file, the only needed key to specify is --recipient, because I only need to specify key to encrypt (receiver key)? I don't need to specify ...
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51 views

What is the recommended procedure to migrate to a new OpenPGP master key?

I am thinking about starting again with a new master key. My current master key was not compromised, but I had stored it on my private server temporarily, which is against good practices (but I am the ...
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GPG Public Key changes after removing master key [closed]

Why does my gpg public key change after removing my master key (leaving just my subkeys) from the gpg key ring? I'm doing this so i can move my daily use keys (subkeys) to my online machine while ...
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47 views

How to decrypt a message using only session key?

I can view a session key to the encrypted data using option gpg --show-session-key <file>. Knowing the session key, how can i decrypt the data without using my private key?
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56 views

Why do I see “Secret key is available.” in gpg when it is not?

My master key is offline and I have subkeys on a Yubikey. As expected, I see sec# when listing keys when using the online system: gpg -K sec# 4096R/2FFA7695 2016-02-01 [expires: 2020-01-31] uid ...
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34 views

Can an OpenPGP master key decrypt something encrypted for a subkey?

When creating OpenPGP subkeys, the master key signs and certifies that a subkey belongs to that master key. Can be used master key to decrypt something encrypted using an encryption subkey? I guess ...
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31 views

OpenPGP master key with certificate and authentication capabilities (on a smartcard)

After researching about OpenPGP and smartcards, I came to a dilemma. The usual setup I've seen more widely is a master key (with SC capabilities) and 3 subkeys (with S, E, A each): pub ...
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What are the advantages to OpenPGP “subkeys”?

I'm trying to get started with OpenPGP encryption. I understand the concept of keeping your master key safe, and using other keys signed by that key (which can be revoked if stolen) for encryption and ...
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Is a 43 character GPG (symmetric) passphrase as secure as a 256-bit key?

A 43 character securely randomly generated mixed case alphanumeric password (with 2 extra chars to give 64 possibilities per character) would constitute 258 bits of entropy (6 * 43 = 258). Since the ...
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42 views

Is a 43 character GPG (symmetric) passphrase as secure as a 256-bit key?

A 43 character securely randomly generated mixed case alphanumeric password (with 2 extra chars to give 64 possibilities per character) would constitute 258 bits of entropy (6 * 43 = 258). Since the ...
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27 views

taking input from webform and piping into bash password prompt

I've been wanting to create a simple web application that would allow me to view certain text files that I've encryped with GnuPG residing on my webserver through any browser remotely. I've figured ...
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How can an MD5-encrypted OpenPGP key be exported without entering the passphrase?

I'm studying cryptography and I have a question about the GnuPG tool for Windows. From what I understand a passphrase is used to hash with MD5 the private RSA key. But when I use the Kleopatra tool ...
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95 views

Decrypt chunks of pgp encrypted

Suppose I have a very large encrypted .csv file (too large to fit in memory). Is there a way to decrypt N bytes of the cyphertext? My goal is to process each row of the .csv in memory without ever ...
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How to export secret keys from GnuPG including photo IDs?

I'm trying to create an OpenPGP key with a photo ID using GnuPG and then export it, so it can be imported on a different computer. Whatever tests I've done the photo ID never appears after the import ...
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27 views

Purpose of secret-subkeys?

Through output of gpg -k und gpg -K it seems that I always have (as well as create) (sub)keypairs. But, if the purpose of the pub and sub is as it is shown below and the purpose of the secretkey is ...
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58 views

What does an OpenPGP signature consist of?

I don't understand how OpenPGP signatures work. I have a picture which I want to sign, and a digital certificate which consists of my name and email address and my public key. Additionally, a digital ...
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65 views

How is this OpenPGP key displaying in a non hexedecimal format?

Looking at a GnuPG manual on openskills, I notice that the main key id GEBV933F is in a different format than the usual hexadecimal (G is no hexadecimal digit). How is this done?
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Comparing allegedly identical OpenPGP keys published through different channels

tldr version: When I try to compare public keys that are supposed to be for the same entity the versions I get through different channels are NOT the same and the ones that I download as a file like ...
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What can I do with the removed Masterkey?

I intend to start using GnuPG respective mail encryption with GnuPG. So I created a key pair with a short expiry date to gain some understanding. I read some stuff about removing the secret masterkey ...
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42 views

Is it possible to have an RSA authentication subkey with a DSA master key?

My key setup is as follows: sec dsa3072/CA72E53A created: 2013-05-12 expires: never usage: SCA trust: ultimate validity: ultimate The following key was revoked on 2016-01-13 ...
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Use GnuPG to verify if specified user signed file

To verify if file is signed correctly we use command: gpg --verify <file_name> and the output shows if file is signed correctly. And if it is, then signer name is shown. But is there ...
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GnuPG asks for a key ID when sharing my public key, what is that?

I generated a public key using GnuPG. I can see it using --list-keys $ gpg --list-keys /Users/mertnuhoglu/.gnupg/pubring.gpg ------------------------------------- pub 4096R/CB3AF6E6 2015-12-24 ...
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64 views

Is there something like a portable GnuPG keychain?

When encrypting or decrypting documents on a computer that isn't my daily driver I need to import my key to the keychain, do the encrypt/decrypt then remove the keychain and from the computer. As a ...
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234 views

GnuPG + Yubikey 4: How to manually check that all keys are where they belong (on the Yubikey only)?

I created a GnuPG RSA master-key and 3x RSA subkeys (sign,encrypt,authenticate). Of course I want all key material to be stored solely on the Yubikey 4 - as they are only my 3 subkeys. Since I use ...
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146 views

Yubikey: How is the OpenPGP key secured by PIN and passphrase?

Using the Yubikey 4 as an OpenPGP smartcard with GnuPG: How is the user PIN and user passphrase secured? In case a sophisticated attacker with physical access to the Yubikey 4 manages to physicaly ...
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GnuPG + Yubikey: Can a trojan extract any secret key or sensitive information?

When using GnuPG with a Yubikey 4 on a Laptop for e-mail communication: Can a trojan extract any secret key or sensitive information? If so, what information would that be?