Questions tagged [gnupg]

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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2answers
255 views

Is it permissible to use GPG without an encryption key?

Will I be disapproved of or get frowned upon a lot if I choose to deploy and use GnuPG without an encryption key? E.g. I generate keys manually and skip the encryption key entirely. The reason is ...
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2answers
1k views

Multiple encryption subkeys on hardware smart cards

I've created a PGP key set which consists of the following: A master RSA key with only signing capabilities, stored offline. Multiple OpenPGP cards, each with three RSA keys: An encryption key A ...
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1answer
133 views

Is GPG symmetric (decryption) vulnerable?

Suppose a file (say, a text file source.txt) was encrypted into danger.gpg using GPG symmetric encryption on a compromised device. Since the device is compromised, danger.gpg could have been created ...
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1answer
403 views

How do I interpret output that produces gpg listing keys?

Correct me where I'm wrong. There are public and private (or secret) keys. A public and a private key make up a keypair. Some keypairs are bound to the other ones. The former are called subkeys, the ...
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0answers
109 views

Import ssh keys into gpg (openpgp) as mutliple authentication subkeys?

I have successfully converted ssh keys to gpg primary keys and then converted them to authentication subkeys using pem2openpgp. Unfortunately there is only one primary key and only one authentication ...
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1answer
216 views

How do I create a detached plain text signature?

If I use gpg --detach-sig file, then I get a small file.sig, but it is not plain text, so this is not useful if you wish to send the signature in a plain text format. If I use gpg --clearsign file, ...
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1answer
148 views

Can I decrypt a .gpg file by using Windows CNG store/ProtectedData?

I'm creating this tool in C# that would take a .gpg file and decrypt it using Windows CNG. I get a .gpg file as my input parameter and it is encrypted with my key using WinPT. Decrypting it works with ...
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2answers
3k views

How to change (sub)key usage of a PGP key?

gpg2 generates keys with one or several of the (S)igning, (E)ncryption, (C)ertification usages set. However, e.g. Enigmail creates a primary key also set for (A)uthentication, which GnuPG then shows. ...
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0answers
123 views

Is gnupg2 --refresh-keys susceptible to any attacks based on fingerprint collisions?

Alice updates her OpenPGP key yearly. Bob updates his copy using: gpg2 --refresh-keys Mallory ensures that Bob uses her keyserver, which offers her own key, which is sharing the 32-bit "short" Key ...
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2answers
148 views

Is GPG a kind of digital signature?

So I've been using GPG since I've touched Linux&LibreOffice, but I only knew that's its a signature, for identifying the work is created by me. But soon I've been touching some law questions and ...
2
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1answer
104 views

Length of a stretched gnupg passphrase that is comparable in strength to an unstretched string of 256 random bits

Assume that we want to encrypt a file with gnupg using AES-256 as the encryption algorithm. (Hence, symmetric encryption.) In this mode, gnupg requires a passphrase from the user. I understand that ...
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2answers
165 views

Is that a good idea? - Firefox/Chrome in-content encryption

I'm currently thinking about writing a Firefox/Chrome and Python/PHP/JS plugin to accomplish the following: Assuming you are on a non-SSL secured site or you simply don't trust any CA like Let's ...
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0answers
86 views

How can I trust a GPG key when I download it based on the fingerprint contained in the file I want to verify?

The instructions at https://tutorials.ubuntu.com/tutorial/tutorial-how-to-verify-ubuntu#3 suggest that you can download an ISO for installing an OS, along with the checksums and a signature. You then ...
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1answer
747 views

RSA 4096 vs. ECC Curve 25519

I want to use GPG to encrypt files before storing them as backup in the cloud. I don't care about interoperability or performance/resource consumption during encryption/decription. I only care about ...
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0answers
58 views

Which encryption algorithm for cloud backup?

I want to backup my data to the cloud. Before that, I want to encrypt it using GPG (gpg (GnuPG) 2.2.11 and libgcrypt 1.8.4). The backup is just for me, so I don't care about interoperability I only ...
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1answer
171 views

Is there a security difference between GPG signing a file directly or its SHA512SUM file?

I am about to decide what SHA-512 hash sum and / or GPG verification scheme I will choose. Let me present you with two options: Signing the 25 GB ~ 23 GiB (one file fit to a Blu-Ray) directly with: ...
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1answer
55 views

Decrypting gpg2-symmetrically-encrypted files using non-gpg2 tools

If I encrypt a file using gpg2 and specifying AES256 as my encryption algorithm, can I decrypt it with tools other than gpg2? More generally, does the fact that one tool used AES256 for encrypting a ...
2
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1answer
253 views

One GPG key with multiple user identities for my career?

I am trying to work out what is the best approach for managing GPG keys over my career when I change jobs. My understanding is that there are two ways this could be done: Have one main/master GPG ...
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1answer
351 views

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 have used. Here's what I managed to do so far. This way I found that my email's ID is 3C76732B: gpg --search [email address ...
17
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4answers
22k views

Can I specify a public key file instead of recipient when encrypting with GPG

Can I do something like: gpg --public-key my.pub -e file.txt If I can, any reason that I should not do that? P/s: I think I don't need to know about the recipient because my machine only has one ...
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2answers
129 views

GPG: Change expected card number

I have switched from a YubiKey 4 to a YubiKey 5. Both have the same GPG keys stored. After storing the key on the first YubiKey, I fetched my public key so GPG knows where to look for the private key. ...
191
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14answers
72k views

Where do you store your personal private GPG key?

So, I want to start using pass, but I need a GPG key for this. This application will store all of my passwords, which means it's very important that I don't lose my private key, once generated. Hard ...
4
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1answer
121 views

I use full-disk encryption. Should I passphrase-encrypt my private key(s) anyway?

Suppose I want to use GnuPG on a GNU/Linux laptop where I've encrypted all filesystems (except /boot) with LUKS/dm-crypt. Backups are encrypted client-side and stored on a physically secure server. ...
7
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1answer
414 views

Preparing to change over to new GPG-key - what to do with my old ones?

I've just created a new off-line GPG-key with a sign/certify master-key and two sub-keys - one for signing and one for encrypting. 5 yr expiration for the master, 2 yr for the subs. My master-key got ...
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7answers
11k views

Is layered encryption more secure than long passwords?

The comments in this question debate about the added security of multi-layered encryption. There seems to be some disagreement, and I thought a proper question would be helpful here. So, to provide ...
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4answers
3k views

How to use multiple smart cards with gnupg?

I have two smart cards: SCard1 and SCard2. The same keys are stored on both of them. One of the feature I use the most is SSH authentication to access multiple servers. But I cannot use the second ...
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3answers
2k views

Where can I find the detailed manual page for gpg --list-secret-keys output

I get confused about the terms used in the output of gpg --list-secret-keys For example what is the meaning of following: sec sec# ssb ssb> there are many codes being used in the output. Can ...
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0answers
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Know the setting used in creating key pair in GNUPG4Win version 3.15

I am using GNUpg4Win version 3.15. For the last few hours I am trying to figure out what default settings are used for Cipher and Hash during key generation. Basically I want to use AES-128, 3DES ...
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4answers
6k views

Is there a limit on the layers of encryption a file can have?

Consider symmetric GPG encryption of a given file my_file.txt. Something like (in command line) gpg --symmetric --cipher-algo AES256 my_file.txt After suppying the prompt with the new password, the ...
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0answers
124 views

gpg2 --full-generate-key generated 2 keys with different expiry dates

I was trying to generate a new gpg keypair earlier, so ran: gpg2 --full-gen-key. I selected the default key type (RSA & RSA), keysize (2048) and specified that the key should expire in 2 years (2y)...
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1answer
131 views

gpg ignores passphrase on my key stored on yubikey 5 nfc

I just set-up my yubikey 5 nfc with 3 seperate subkeys (S, E, A). While encrypting and decrypting works fine (self-tested), I'm questioning the fact that gpg only ever asks me for the yubikey's pgp ...
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0answers
72 views

Is GPG's AES encryption that much stronger than its RSA headers? [duplicate]

Correct me if I'm wrong at any point of this questino. I understand that AES is a lot cheaper to compute than RSA (or any form of asymmetric encryption) and that that is why GPG and similar programs (...
4
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1answer
111 views

How do GnuPG smartcard generate reliable random data?

I'm generating a private key on my new GPG smartcard at this very moment. On linux, the random would be fed by the keystrokes on my keyboard, the network packets, the mouse movements etc. How does ...
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0answers
67 views

How to display the SHA256 hash while signing or in signature

I realize (using --clearsign) that GnuPG is using SHA256 as the hashing algorithm for signing, but I would like to be able to see the actual SHA256 hash in the signature somewhere. Is there a way ...
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2answers
22k views

gpg: decryption failed: No secret key

I cannot seem to get gnupg to decrypt files encrypted with my keys. I've tried migrating my secret key from an old laptop to a new one, and I keep getting the same error: gpg: decryption failed: No ...
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1answer
90 views

What are a keypair and a public key ring?

The GNU Privacy Handbook says: The command-line option -gen-key is used to create a new primary keypair. gpg --gen-key Does a keypair mean a pair of private key and public key? The book also ...
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1answer
225 views

Why is GPG-agent still caching my passphrase?

I can not get gpg to prompt me for my passphrase when I want to decrypt a file. I tried including: default-cache-ttl 0 max-cache-ttl 0 (also flipped the bit to 1) within ~/.gnupg/gpg-agent.conf ...
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1answer
105 views

OpenPGP SmartCard: generate revocation certificate on-card?

As far as I can tell: It is possible to generate a private keyring (i.e. signing private key, plus associated encryption private key and authentication private key) entirely on an OpenPGP Smartcard (...
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1answer
26 views

Leaking `.gnupg` directory when private keys are stored on a smart card

What security risks can be caused by leaking .gnupg directory (for example, accidentally committing it to GitHub) when private keys are stored on a smart card?
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7answers
13k views

Putting my PGP ID/link on printed business cards

I'm going to print some business cards, and along with my email address I was thinking of putting my PGP ID on it as well. After doing some research I found that using the short ID is not a good idea....
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1answer
1k views

OTP vs. U2F for online banking and email (vs. store key on USB)

Which one among OATH HOTP, OATH TOTP on one side (say in the form of a credit card-sized token) and U2F (say in the form of a USB key) on the other side you think is more secure for purposes like ...
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0answers
63 views

Import GnuPG Subkey to other Primary Key

Let's say we have two gpg primary keys "Ident-A" and "Ident-B". There is also a subkey "Sub1" used for encryption by "Ident-A". It is possible to add a subkey "Sub2" to "Ident-B" using the private key ...
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2answers
250 views

On gpg2's symmetric decryption

According to an answer and comments in a earlier question of mine, when one uses gpg2 to symmetrically encrypt a message, gpg2 randomly generates a one-time encryption key for that message, as well as ...
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2answers
26k views

What is the default cipher algorithm for GnuPG?

I know, that one can force GnuPG to use AES256 for encryption with gpg --cipher-algo AES256 or with a special setting in ~/.gnu/gpg.conf. But, what is the default cypher algorithm for GnuPG, if I ...
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1answer
119 views

On the use of gpg2 for long-term encryption

I am looking for tools/libraries for symmetrically encrypting millions of files (many terabytes' worth of content). In particular, I am exploring the possibility of using gpg2 for this1. One concern ...
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1answer
371 views

The passphrase in gnupg's symmetric vs asymmetric encryption schemes

This question is admittedly artificial. Its purpose is only to help me understand aspects of gnupg that I can't figure out from reading the documentation. One thing that puzzles me about gnupg is ...
3
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1answer
517 views

How can I generate a .gpg file for verifying Putty?

I downloaded the Putty installer from ssh.com, which said To import the signature key into GPG, use: gpg --import putty-release-2015.asc To check the signature of a file, use: gpg -...
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1answer
230 views

I can't get gpg-zip to work. What am I doing wrong?

I haven't used gpg-zip before. I am trying to compress and encrypt a directory with more than 200 files. I did a test run with a smaller directory containing just a dozen PDFs in it, a folder I'll ...
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0answers
86 views

What are the possible ways to manage gpg keys over period of 10 years?

What key curation can be applied to a personal gpg keypair over a period of time (e.g. 10 years) if I also want to use the keypair for professional use? What are the measures that I need to take to ...
4
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1answer
809 views

Correct way to replace a GPG key

I want to create a new GPG key with a longer key size. What are the best ways to replace the key ? My current key is associated with a lot of stuff like GitHub etc. Should I revoke my old key and sign ...