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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How do I decrypt encrypted text using a public_key.pem and an unknown hex data file?

I have been given a 3 files by a client: A public key (text file that begins with 'Begin Public key') An unknown file type containing some hex data - 'smthing.uyu' (most likely the private key?) ...
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OpenPGP (RFC4880) - do you agree with my SimpleS2K (string-to-key) implementation?

Background: I'm writing a GPL Python OpenPGP to JSON parser which I'm testing on files generated with GPG 1.4.16. If given a passphrase, the parser will generate keys using the string-to-key methods ...
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26 views

Short OpenPGP key IDs are insecure, how to configure GnuPG to use long key IDs instead?

Short OpenPGP key IDs (with 32 bits / 8 hex characters) are subject to collision attacks. It is strongly recommended to stop using 32 bit IDs: Stop using 32bit key ids It takes 4 seconds to ...
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14 views

Verify GnuPG download with signature file - and it fails

I'm trying to verify the new GnuPG download (for OS X) using GnuPG. (First of all I'm not sure if you should verify a file with the old version of it, which I probably didn't verify back then to be ...
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19 views

GPG: Detaching Public Subkeys - why can't I do it?

I understand the benefits of using subkeys. I also know that, in the case of private keys it is possible to detach the subkeys from the master key, since there are times when a user may prefer not to ...
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61 views

RSA key generation: gpg vs openssh

When I generate RSA key for ssh (both server-side and client-side): dpkg-reconfigure openssh-server ssh-keygen the key generation is completed instantly. However, when I generate RSA key for gpg, ...
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438 views

Why does GnuPG shrink my file after elgamal encryption?

I would like to run GnuPG elgamal encryption for at least a few minutes. The only way I can think of is to create a large file to be encrypted. So I created my file like this: dd if=/dev/zero ...
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38 views

“gpg” vs “openssl rsautl” (asymmetric keys) for credentials storage

I'm working in a PHP project and need a better solution to store credentials to a client's database, and I'm thinking about encryption, I put to work both gpg and openssl using asymmetric keys, but ...
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3answers
142 views

Sending an encrypted PGP email to someone who doesn't yet have my public key

Suppose I have the public key of a recipient I'd like to send an email to, and I've never sent this person an email before. Does it make sense to encrypt my first email to this recipient and also ...
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45 views

Ability to determine which PGP public keys a message has been encrypted for?

Is it possible to determine, given a PGP message that you can already decrypt, to determine which other PGP keys that message has also been encrypted for?
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37 views

Change the preferred algorythm from AES to Camellia in an existing PGP key [duplicate]

I already created a PGP key-pair in Thunderbird Enigmail on Ubuntu. Now I would like to change the key, so it uses preferably Camellia-256 for encryption. How can I change the preferred algorithm ...
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generating public/private credentials for MS Outlook email encryption [migrated]

An app running on a CentOS 7 web server needs to receive encrypted emails sent from users of MS Outlook. Can someone please provide explicit instructions as to how I can generate or procure all of ...
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351 views

When signing email with GPG, how does verification by the receiver work?

I use GPG to sign my outgoing emails. I understand how it works when I encrypt mail to send to someone else. Then I need his/her public key, encrypt it with that, and only he can decrypt it using ...
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92 views

How to change default cipher in GnuPG on both Linux and Windows?

How can I change the default symmetric cipher used by GnuPG from CAST5 to another? I'm using GPG4Win on Windows, but would also be interested in a solution for Linux.
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56 views

If OpenPGP insecure if it only supports PCKS#1 v1.5?

I've just read the RFC 4880 specs and there is nothing about OAEP; only PKCS#1 v1.5. If it is true that the OpenPGP-standard only supports the PKCS#1 v1.5 padding-scheme, is this a security issue? ...
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114 views

How do PGP keyservers synchronize the keys?

I want to know technical details about how public PGP keyservers synchronize the keys. If I send my key to one keyserver, how exactly does it "travel" to all the other ones? Who sends it to who and ...
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57 views

Why should I have my GPG key expire? [duplicate]

When creating a key pair using gpg it asks me for an expiration date: $ gpg --gen-key Please specify how long the key should be valid. 0 = key does not expire <n> = key expires ...
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57 views

When should I sign a PGP key with a non-revocable signature?

GnuPG allows the user to sign a key with a non-revocable signature. I have done this when I’m signing one of my own keys—signing my personal key with my work key, for instance. Is there any other ...
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35 views

Implement GPG Verification (Bitcoin-OTC)

I'm looking to implement a "Verify with Bitcoin-OTC" feature for my web app. The general idea is the user would prove he owns a particular account on the external site Bitcoin-OTC and my app would ...
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1answer
239 views

Can OpenPGP private keys ever be secure enough to store publicly?

The OpenPGP (private) key format stores the key symmetrically encrypted. The "iterated and salted" setup derives this key from a passphrase, taking a "octet count" parameter that determines the ...
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2answers
167 views

Why gpg-signed files differ every time

I signed the same file producing a separate file for the signatures, and I noticed that every file is signed with a different signature. I don't get it. Shouldn't it always be signed with the same ...
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Has my GPG subkey been uploaded to the keyserver?

I've been trying out the new ECC keys that have been added to GnuPG 2.1. I created a primary key, then added an ed25519 signing subkey. So I know get this: ➜ ~ gpg2 -K ...
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94 views

Key generation: Differences between GnuPG classic, stable, modern?

I plan to create a 4096 bit RSA&RSA key pair: gpg --gen-key --personal-digest-preferences SHA512 --cert-digest-algo SHA512 Is there any difference in generated key quality between versions 1.4 ...
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1answer
43 views

Upgrading OpenPGP public key on key servers?

What is the best way to upgrade an OpenPGP key that was created 11 years ago? It's 1024-bit and is published on the key server. I can create a new key, but what's the proper way to update the ...
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How much risk is introduced by git's signing the commit hash rather than the blobs? [duplicate]

Since first switching from centralized VCS systems to a decentralized one—specifically git—I have properly understood that that git's commit ID's were hashes of the included objects and some meta data ...
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301 views

How easy is it to crack gpg with private key, but without password

I was wondering if an adversary have your private gpg key but not the password/phrase, how easy/difficult would it be to crack a encrypted file compared to a encryption that only use password and not ...
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73 views

What exactly is a subkey?

I fairly understand the math behind RSA, Elgamal, AES, SHA but not how things are used in practise. How are subkeys different from master key? I understand its purpose from various websites but How is ...
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81 views

How to avoid identity theft at key signing parties?

Let me begin by distinguishing two kinds of identity theft: Conventional identity theft (e.g. using credentials from ID documents, bank accounts, etc, to commit fraud or other mischief). ...
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What concrete parameters can I change to make my passphrase-protected private gpg key more secure

There are several questions which discuss the resistance of passphrase-protected private gpg keys against brute force attacks. It seems, this kind of discussion could go on forever. Rather than ...
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55 views

How should I organize my keys?

Suppose I have a set of computers with variegate level of trust (for example): I fully trust my own desktop pc at home I trust a bit also my smartphone, but I know it could be stolen I trust a bit ...
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1answer
69 views

Do I have to use an IV when using GPG with AES 256?

Do I have to use an IV when using GPG with AES 256? Or does GPG handle that for me? I've noticed that I get different results each time I run the encryption, i.e. gpg --symmetric --cipher-algo ...
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106 views

Why is GPG encrypted message size not proportional to number of recipients & file size?

I have noticed that when I am using GnuPG to encrypt a file for multiple recipients, the size of the encrypted message does not seem to be directly proportional to the number of recipients. For ...
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25 views

Can I store a GPG revoke certificate online?

It's clearly a good idea to store the revocation certificate in a way which is both secure and reliable. Cloud-based storage services are great for reliability, but of course they lack of security. ...
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76 views

Is it possible to export a GPG subkey's public component?

I'm trying to export the public component of my subkey, but all GPG will give me is the public component of my master key. The keyring is set up like this. $ gpg -K /home/alex/.gnupg/secring.gpg ...
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122 views

What is an OpenPGP Key ID collision?

Recently an Evil32 project group announced that they have found collisions for all OpenPGP keys from public keyservers (https://evil32.com/). What does the term collision refer to?
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101 views

Why can't I upload a new ECC key to key servers, which is supported by GnuPG 2.1?

My OpenPGP key is soon to expire so I wanted to create a new one. GPG 2.1 came out a month ago including ECC support and I wanted to try the new key types. So I have generated a brand new ed25519 ...
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44 views

Which actions does the GnuPG “Certify” capability permit?

Of the following three actions: Certifying / signing other people's public keys. Generating a revocation certificate. Adding & revoking subkeys. ... which ones does the Certify capability on a ...
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50 views

What is 0xXXXXXXXX.asc.sig and how can I generate this?

When I am exchanging PGP keys with someone, I receive the regular 0xXXXXXXXX.asc file and regularly receive a file called 0xXXXXXXXX.asc.sig. What is this file? How can I generate one and send it ...
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91 views

GPG Web-of-Trust Level [duplicate]

(and really sorry for my english) I have a question about Web-of-Trust of GPG. Let's say A and B signed each other's public keys and B and C signed each other's public keys. In this case A can trust ...
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908 views

New PGP key: RSA/RSA or DSA/Elgamal?

I wanted to create a new PGP key using GPG Keychain Access on my Mac. One of the options was to choose keytype: RSA and RSA DSA and Elgamal RSA (Sign only) DSA (Sign only) I found this Superuser ...
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Distributing public keys; with or without a sub-key?

Most of the public keys I am getting from friends have a sub key in addition to the pub key. For educational purposes I retrieved some public keys and came across this Linus Torvalds' key that does ...
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36 views

What is validity in terms of PGP 6.5.8?

In PGP 6.5.8, there is a concept of "validity" for a key, and it shows in the user interface for each key on the keyring. What is this concept, and how to you set it so a key is considered valid?
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Why the symmetric key is added to the message?

Yesterday in my class we learnt how to send a message from Alice to Bob with the achieved goals of confidentiality, integrity and authenticity. In order to have a better performance we use a hybrid ...
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1answer
116 views

Is an anonymity network like Tor viable on top of the GPG web of trust?

The web of trust is a graph where the vertices are GPG users (actually, their keys) and the edges are cross-signatures. If we put issues of owner trust aside and assume that all participants only sign ...
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What is the difference between a key algorithm and the encryption algorithm?

I just starting to learn about PGP encryption. One thing that confuses me is the difference between a key algorithm, and an encryption algorithm. For example, lets say I have a trading partner (EDI ...
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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 ...
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90 views

What is the difference between “unknown” and “undefined” trust?

When you trust a GnuPG key, you can choose one of these five options (and I'm assuming the same options exist in other OpenPGP tools): 1 = I don't know or won't say (undefined) 2 = I do NOT ...
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206 views

What is the difference between “full” and “ultimate” trust? [duplicate]

When you trust a GnuPG key, you can choose one of these five options (and I'm assuming the same options exist in other OpenPGP tools): 1 = I don't know or won't say (undefined) 2 = I do NOT ...
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1answer
118 views

Is the PGP Web of Trust / Keyserver infrastructure permanently broken?

I love the idea of decentralized trust, the web of trust, and the fact that anyone can run their own keyserver and isn't beholden to a centralized point of failure. But does the decentralized ...
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130 views

Is it necessary to remove the primary secret GPG key from your laptop if it has full-disk encryption?

According to a number of articles, e.g. "Creating the Perfect GPG Keypair," it is advisable to have a number of subkeys in your GPG key, one for encryption, and one for signing, and then to (a) back ...