Questions tagged [openpgp]

An open source version of the PGP (Pretty Good Privacy) encryption / decryption software. Primarily used for securing email communications.

Filter by
Sorted by
Tagged with
0 votes
0 answers
23 views

Do I have to check the fingerprint of new received OpenPGP public key, if it has been sent in a signed and encrypted email from a verified source?

I asked this question before at https://askubuntu.com/questions/1404973/do-i-have-to-check-the-fingerprint-of-new-received-openpgp-public-key-if-it-has and the answer to my question was "This ...
user avatar
0 votes
1 answer
47 views

Extract OpenPGP secret key material to use as X.509 root CA's key

At the moment, there are 2 cryptographic setups in place on the devices I use daily: First, I have an OpenPGP key that I use to sign email, authenticate over SSH, and various other little things. Put ...
user avatar
0 votes
0 answers
293 views

Changing the encryption algorithm used for PGP/GPG private key

I've read a number of posts regarding changing the algorithm used to encrypt my private PGP keys. However, nothing I have tried seems to work. I am using gpg4win: gpg (GnuPG) 2.3.4 libgcrypt 1.9.4 ...
user avatar
0 votes
1 answer
202 views

How best to cryptographically sign scientific papers?

Academia has had some high profile cases of forged identity; for instance, in the last decade the publisher Springer has had to retract 62 papers for this reason alone. Usually these aren't high-...
user avatar
  • 171
0 votes
0 answers
59 views

Can GnuPg flag as invalid if it receives a key for a uid (the email) where the email is found on a keyserver, but not with that key?

I created a test key to share with someone for the purpose of debugging a client issue. However, I did not transmit that key to a key server, and it still uses my email. The key server locally that my ...
user avatar
2 votes
1 answer
174 views

Does gpg (or openpgp in general) authenticate symmetrically-encrypted data?

When using gpg --symmetric to encrypt a file/message with a passphrase, is there any cryptographic integrity check to prevent an attacker from modifying the ciphertext? E.g. does gpg (or any other ...
user avatar
  • 38.7k
3 votes
1 answer
487 views

GnuPG now uses ECC 25519 as default on new key generation - any compatibility issues to worry about?

TL;DR: I'm assuming that if GnuPG made it a default then it should be what we use, but it used "bad" defaults in the past so I'm wondering if there are any tradeoffs to this? More ...
user avatar
  • 33
2 votes
2 answers
744 views

How to get PGP key passphrase out of Thunderbird?

I set up Thunderbird to use PGP a while ago, so I can sign and decrypt messages now. But I have forgotten my private passphrase for my private key, but since Thunderbird can do it anyway, it has it ...
user avatar
0 votes
0 answers
37 views

OpenPGP: What happens if I have two keys on the same email and try to encrypt a message with that recipient? [duplicate]

Let's assume that I saved two OpenPGP keys(key1 and key2) on the email mail@mail.com. What would happen if I try to encrypt a message with the following command: gpg --encrypt --recipient mail@mail....
user avatar
  • 101
4 votes
1 answer
296 views

What metadata is exposed by OpenPGP?

Say I have a file encrypted with GnuPG, in isolation (i.e., I don’t have the relevant keys). Can one then establish the recipients of the encryption? That is: Name/E-Mail/Comment Key ID Or is this ...
user avatar
0 votes
2 answers
344 views

Any reason why SHA-3 isn't yet present in GnuPG?

I was curious about setting SHA-3 as the preferred hashing algorithm for GPG but that looks like it is not yet supported and the documentation states this: SHA-3: SHA-3 is a completely new hash ...
user avatar
1 vote
1 answer
227 views

GnuPG: Why is my Ed25519 signature 144 bytes long rather than 64?

according to https://www.rfc-editor.org/rfc/rfc8032 EdDSA uses small public keys (32 or 57 bytes) and signatures (64 or 114 bytes) for Ed25519 and Ed448, respectively; But if I sign using Ed25519 in ...
user avatar
9 votes
0 answers
329 views

PGP security with Thunderbird 78 email client

I have a query regarding best practice of using PGP to sign emails with Thunderbird 78. Thunderbird 78 took an existing system by Enigmail and brought it "in-house" to be built into the ...
user avatar
  • 1,057
0 votes
2 answers
216 views

No expiry for offline primary PGP key?

Are there benefits to set an expiration date on a PGP primary key which is only used offline? Is setting an expiration date only on the subkeys enough?
user avatar
  • 493
0 votes
1 answer
157 views

How many keys do you use for signing and encrypting emails? [closed]

Situation I have a university Gmail email address. I'm trying to migrate away from sending emails with the Gmail web client to one I have more control over like Thunderbird. It's also because Gmail ...
user avatar
1 vote
2 answers
912 views

Create CSR for S/MIME certificate from existing OpenPGP key pair

While increasing my communication security as much as possible, I came across OpenPGP & S/MIME and already use an OpenPGP key pair in both of my mail clients (PC & smartphone). I believe the ...
user avatar
  • 113
0 votes
1 answer
161 views

keys.openpgp.org keyserver fails to send confirmation mail to an Outlook-address

I uploaded my master key's public part to the keys.openpgp.org-keyserver. It has 4 UIDs set up (4 different e-mail addresses) and each of them are correct and valid e-mail addresses. The keyserver ...
user avatar
2 votes
1 answer
167 views

A solution for the absence of Certifying Subkeys in OpenPGP Certs

As discussed in this answer, gpg does not offer the capacity for subkeys to certify (eg. "sign") other keys, though there may be good reason why it should, and they do sign at least one key. ...
user avatar
  • 193
1 vote
1 answer
903 views

GnuPG - connecting to specific card reader when multiple reader available

Currently I can use $ gpg --expert --card-status to interact with smartcards that run the OpenPGP applet. Through trial-and-error, it seems that only the first card reader will interact with gpg. ...
user avatar
  • 142
0 votes
1 answer
471 views

How long does it take for a gpg key revoke certificate to propagate to all public key servers?

I recently created a new gpg key just for the sake of learning the basics of public key encryption. Now, I'd like to revoke that test key so that I can go on using a more "permanent" key that is ...
user avatar
  • 3
4 votes
2 answers
547 views

Yubikey PGP migration

I am currently using a Yubikey 4 with my PGP subkeys on it. My mainkey is stored within Kleopatra. As I am planning to move over to a new Yubikey 5 I have asked myself if it is possible to still be ...
user avatar
0 votes
0 answers
387 views

How to automatically sign a message using PGP in an email?

Is there any way to sign and send a message from email server automatically...without using any desktop client to sign the message. For Example, A wants to send a message to B. A open its email ...
user avatar
-2 votes
2 answers
658 views

How does PGP Public and Private Keys work?

I recently tried to understand how PGP works: I encrypt plaintext with my private key and if I send that encrypted text to others with my public key they can encrypt that with my public key?
user avatar
0 votes
0 answers
788 views

changing passphrase on gpg subkey

Is it possible to change passphrase on a subkey by: gpg --edit-key sub_key_id passwd Or will this change the passphrase on the master key as well? (My idea stems from the fact that master key is ...
user avatar
  • 393
1 vote
1 answer
177 views

Web of trust and signature types? (sig1, sig2, etc)

I have read about The OpenPGP trust model but I don't see any mention of the specific signature types. Are all signature types (sig0 - sig3) treated the same by tools such as gpg or the PGP ...
user avatar
2 votes
0 answers
160 views

How to list signatures of public key file without importing it to keyring?

How can I list all signatures made to a public OpenPGP key without importing it? A file with the public key is available. I would like a similar output to gpg --list-signatures <key-id>, but ...
user avatar
1 vote
0 answers
96 views

OpenPGP and 3 Yubikeys, Best Practice for Encryption Subkey

New to OpenPGP. I have 3 Yubikeys, one for my laptop, one for my desktop, and one which I plan to keep in cold storage as a backup. My plan was to create a S/E/A subkey for each Yubikey, attached to ...
user avatar
  • 111
0 votes
1 answer
91 views

Can I resubmit my GPG key to a keyserver?

I submitted my GPG key to the keyserver earlier. Now I got signatures on my key. Can I republish it? gpg --send-keys doesn't seem to alter my key any more, but doesn't spit out any error either.
user avatar
3 votes
1 answer
96 views

Can any private key information be exposed when signing an email? [duplicate]

So I know that PGP encrypted email can be vulnerable to a known-plaintext attack from a known, consistant email footer or greeting (“Hello”, “Yours truly, xxx”, etc), but does the same thing apply to ...
user avatar
  • 31
1 vote
1 answer
245 views

alternatives to the "PGP pathfinder" [closed]

The author of the PGP pathfinder deceased this year. Shortly after the data was not updated any more. Are there any alternatives known to find signature paths?
user avatar
2 votes
1 answer
6k views

How do PGP keys "expire"?

When creating a PGP key, you can choose when the key "expires". What does this mean and how does it work?
user avatar
0 votes
1 answer
325 views

secp256k1 GPG key?

Given that secp256k1 is used to underpin the entire Bitcoin network (worth $174B as of today) -- it appears to offer demonstrably better security than other EC curves as no one has yet taken the ...
user avatar
2 votes
3 answers
748 views

In PGP how can I be sure about the public key?

I was reading about Protonmail's system and I couldn't find an anwser to something. In PGP communication is encrypted using assymetric cryptography: public and private keys. If you want to send ...
user avatar
  • 131
1 vote
1 answer
1k views

Difference between OpenPGP symmetric encryption and AES-256?

I would like to understand the difference between: OpenPGP symmetric encryption and AES-256 using Winzip/7-zip? I mean if you encrypt a file with an OpenPGP program like GnuPG, using AES-256 ...
user avatar
  • 133
3 votes
1 answer
635 views

gpg: Every private key export (of the same key-pair) is different

gpg version: 2.2.16 (as part of Gpg4win 3.1.9). Is this supposed to happen: Every export of my private key partially differs from every other export as follows: 2 middle chunks of the main block, and ...
user avatar
1 vote
1 answer
335 views

Creating pointers to keys on SmartCard

I am new to OpenPGP and SmartCards but I cannot find how to do a fairly straight-forward task. I am trying to sign a file with a private key stored on a YubiKey device. Here is my session: $ ...
user avatar
4 votes
0 answers
215 views

Should I use the same OpenPGP keys in certificates used to provision the YubiKey PIV slots?

I know PIV and OpenPGP are separate standards and independent applications in the YubiKey, but for newcomers like me they look very similar with their signing, encryption and authentication keys, use ...
user avatar
  • 41
5 votes
2 answers
6k views

How do I delete secret subkeys correctly?

I tried to use gpg --delete-secret-keys to delete some revoked subkeys but ended up accidentally deleting my primary key instead. I was able to reproduce my mistake with the following commands: $ ...
user avatar
4 votes
1 answer
1k views

GnuPG can see a card under root user, but not under normal user

When under an unprivileged user: $ gpg --card-status gpg: selecting openpgp failed: No such device gpg: OpenPGP card not available: No such device With sudo or under a root user: $ sudo gpg --card-...
user avatar
  • 414
1 vote
0 answers
78 views

Can I use my Microsoft Outlook S/MIME certificate with gpgsm.exe

So I work for a large company that has their own internal CA and maintains their own set of S/MIME certificates. We periodically have to re-enroll in S/MIME and import the certificate into Microsoft ...
user avatar
  • 123
4 votes
1 answer
166 views

Is forward secrecy useful for an application where keeping message history is an integral part?

I am writing a decentralized application that lets certain privileged users post messages to other users. These messages should be encrypted so that only the two of them can read it. Messages are ...
user avatar
1 vote
1 answer
353 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 ...
user avatar
  • 123
1 vote
1 answer
325 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 (...
user avatar
2 votes
3 answers
733 views

With GPG, can 3rd party verify that message has been encrypted by specific public key?

Bob is sending message X to Alice. He encrypts X with Alice's public key using gpg and sends her encrypted message (ciphertext). Later Alice claims that Bob made a mistake and the ciphertext was not ...
user avatar
  • 123
3 votes
1 answer
335 views

Are there any known collisions of a "long" (64 bit) OpenPGP key ID?

We know that the "short" 32 bit OpenPGP key IDs can be easily brute-forced and the recommendation is to use the "long" 64 bit IDs or full 160 bit SHA1 fingerprint. However I am concerned that the "...
user avatar
1 vote
0 answers
150 views

Help me understand Encryptpad and 7-zip for encryption

I was looking to encrypt some text files (containing sensitive data) so I could safely keep them online (e.g. Google drive). I have found three options: 7-zip, which does AES-256 Encryptpad, which ...
user avatar
  • 133
3 votes
2 answers
158 views

Delivering data securely when the data source is the key maker

Let's say we have the following: Bob needs to send data securely to Alice. Only Bob and Alice are allowed to read/see that data. Alice is not able/allowed to create keys. Alice can use any number or ...
user avatar
3 votes
1 answer
119 views

How to prevent participants from cheating when establishing an OpenPGP-like structure

I would like to share documents within groups and make sure that the member of each group can only access the documents shared in his/her group. I also want to make sure that non of the parties can ...
user avatar
1 vote
1 answer
85 views

Share Document within user group

I would like to share documents within groups and make sure that the member of each group can only access the documents shared in his/her group. Situation: There are 5 participants (A, B, C, D). ...
user avatar
1 vote
2 answers
1k views

What does the 'Sign' and "Add to recipients' means in GPG keychain?

Hello everyone, I just newly get to know the existence of GPG keychain. After error and try I now understand most of the functions of this software . However the two checkbox in this picture remains ...
user avatar
  • 11