PGP is short for "Pretty Good Privacy". It is a data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. PGP is often used for signing, encrypting and decrypting texts, E-mails, files, directories and whole disk partitions to ...

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12
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3answers
3k views

Why do PGP master keys only have a single subkey, and tie certification with signing by default?

After learning more about PGP subkeys and how to split apart the roles of (S)igning, (E)ncryption, (A)uthentication and (C)ertification, I discovered that in most cases(?) a default master key has a ...
3
votes
2answers
120 views

How to properly transition from standard PGP keys to using subkeys?

When I initially set up PGP, PGPTools didn't prompt me to create separate subkeys, as explained in the article "Creating the Perfect PGP Keypair". Now that I've learned a bit more about PGP, I'd like ...
3
votes
1answer
29 views

PGP Owner Trust Field & Signature Trust Field Distinction

I'm reading Cryptography and Network Security Principles and Practices (5th ed, p584) and reading about PGP keyrings, I'm a little confused about the differences between the owner trust field and the ...
2
votes
1answer
36 views

GPG: What public key do I have to publish?

I just created a master key and two subkeys. The first subkey is used for encryption, the second one for signing. Now i am wondering what public key do I have to publish on my website. Does is ...
0
votes
2answers
58 views

Is it possible that to sign a message with a PGP key in a way that leakes the key

Alice provides a software for signing messages. The software runs in a airgapped enviroment. The software is given the message that's to be signed and the private key. The software then produces a ...
4
votes
2answers
119 views

Is it possible and does it make sense to sign an E-mail with PGP and S/MIME?

After some research without any answer to my question, if it's possible and does it make sense to sign an E-mail with PGP and s/mime (?), I'm hoping to get an answer here. I know that, PGP and S/MIME ...
6
votes
4answers
375 views

Establishing a Reputable Pseudonym with PGP Key

This has become a bit of a thought experiment for me. Suppose someone would like to establish a pseudonym along with a corresponding PGP Key, how could other people verify the correspondence between ...
0
votes
0answers
32 views

What is the best online email client which supports GPG? [migrated]

I am looking for an online email client which supports GPG (or PGP). I know it is not suggested for the privacy and safety but for a reason I need it. Do you know any good online service for this ...
4
votes
1answer
80 views

Can I check who can decrypt my GPG message after I encrypt it?

When I send, say, a great recipe for funnel cake to Alice and Bob using GPG, I can be pretty sure they will both be able to decrypt it. However, can I be certain, or prove after the fact, that they ...
3
votes
1answer
75 views

PGP key on smart card: why do I need a “secret key” on disk?

I have a YubiKey NEO on which I have the OpenPGP applet and I have a PGP key installed. I work on 3 different computers and I initialized the card on computer bob. I'm now at computer rob. Someone ...
4
votes
2answers
76 views

Do GPG and OpenSSH use key stretching on their keypairs?

Both OpenSSH and GPG can generate key pairs which are stored as files in well-known paths inside the user directory. A passphrase is always asked for during the generation process, which is then used ...
1
vote
0answers
30 views

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 ...
2
votes
4answers
36 views

Is PGP or S/MIME useful when both servers are self-controlled?

With regards to encryption and preventing a 3rd party from viewing my emails (and ignoring validity/signing), is encrypting an email via PGP or S/MIME useful when I control my server and my recipient ...
0
votes
1answer
53 views

What is the risk of using SHA1 in PGP email signatures?

SHA-1 is being phased out by a lot of major companies due to vulnerabilities. For example Chrome no longer considers it safe for public web PKI. Is it insecure to use SHA-1 for PGP email signatures?
2
votes
2answers
236 views

Would Axolotl Ratchet protocol be suitable for encrypting email communication?

Axolotl Ratchet is used by Textsecure and is an enhanced version of OTR in a way to make it suitable for mobile applications, which has the probability to encrypt messages without both parties to have ...
2
votes
1answer
45 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 ...
29
votes
4answers
20k views

How does PGP differ from S/MIME?

Is S/MIME an abstracted system for general MIME type encryption, whereas PGP is more for email? Why would I want to choose one over the other, or can I use both at the same time?
5
votes
1answer
213 views

What are the security differences between SMIME email and PGP email? [closed]

Outside of key distribution, and specific to the technical details relating to encrypted email data (message body), what's the difference between SMIME and PGP? Example comparisons Security ...
4
votes
1answer
111 views

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 ...
5
votes
2answers
80 views

Why don't PGP keyservers enforce double-opt-in?

One thing that I found out when starting using PGP: When I uploaded my keys to the SKS keyserver, the keyserver did not take any action to verify that I am who I claim to be. Since a PGP key contains ...
1
vote
1answer
39 views

Using scrypt to encrypt data in a session variable

Let's say I want to store some data in the node's session, for example, like an authenticity token. Obviously I want to store it in an encrypted way if it's going in a cookie, then decrypt it on a ...
1
vote
1answer
38 views

PGP: Can I just upload my public part of encryption sub key to PGP server?

I'm a little bit confused here, since the best practice suggests that main key should be completely offline, so which key should I upload to the public directory? Here's what I have: main key (sign ...
2
votes
3answers
200 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 ...
3
votes
1answer
57 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?
4
votes
2answers
398 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 ...
-1
votes
1answer
45 views

Do we need to same PGP version for decryption [closed]

Requirement: In our company Location A uses PGP encryption and sending data over internet. In Location B, we have to decrypt the file. Question is what do we require in Location B Do we need to ...
1
vote
1answer
139 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 ...
1
vote
1answer
30 views

Should I verify installer file PGP hash?

Let's say that I'll download an installer for a program on Windows and the publisher has released PGP Signature for the file. The installer file does not have any code signing certificates. If I ...
3
votes
2answers
90 views

PGP question decrypting my own message from 2 days ago

I have recently started using pgp and am still in the infancy stages with knowledge. i sent a friend an encrypted message using pgp4usb. a few days later they responded, with relevant info, being ...
6
votes
1answer
75 views

User IDs containing URIs

When adding a User ID to your OpenPGP key, you are typically asked (for example by GnuPG) to provide a name, a comment, and an email address (where each part is optional). This format (Name (Comment) ...
4
votes
1answer
62 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 ...
2
votes
1answer
49 views

How are private keys encrypted?

I've just got back into the swing of using pgp and I'm wondering how the private key is encrypted (using the passphrase to decrypt). This has got to written down somewhere, but in my searches the vast ...
-2
votes
1answer
605 views

Safest and most secure way for backing up private data

Here is what happened, I first collected my data into one folder,tar'd it, encrypted it with gpg, put it in truecrypt container, and after that started to copy the container to another place, but ...
1
vote
1answer
38 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 ...
13
votes
3answers
4k views

ECC in (Open)PGP

How is with the support for ECC (Elliptic Curve Cryptography) in (Open)PGP so far? It seems that GnuPG (The GNU Privacy Guard) doesn't have an official implementation - but I did find the gnupg-ecc ...
1
vote
1answer
59 views

What do I do about a forgotten, ancient PGP key?

So I just created a new PGP key because I want to start using PGP to encrypt my emails. Lo and behold, this is apparently not my first attempt to use PGP. Five years ago, I created another PGP key ...
0
votes
1answer
82 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 ...
0
votes
1answer
131 views

PGP Key publishing on MIT PGP Public Key Server [duplicate]

I have a public pgp key, so that users can send me an encrypted message. Ofcourse, any user that wants to send me a message, wants to verify that the public key (s)he has, really belongs to me. From ...
2
votes
1answer
95 views

Threats against website running without TLS but with PGP messages

Are there any threats against a web site that isn't running SSL but uses PGP to encrypt all information to the server (except session identifier) The information flow is as such: 1. Session ID set on ...
2
votes
1answer
245 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 ...
79
votes
7answers
40k views

How should I distribute my public key?

I've just started to use GPG and created a public key. It is kind of pointless if no-one knows about it. How should I distribute it? Should I post it on my profile on Facebook and LinkedIn? How about ...
12
votes
3answers
2k views

Does GPG key expiration add to security?

I've created a new GPG key to sign a software package in a source repository with an expiration date three years from now. It seemed like a good security measure because if the key is compromised or ...
0
votes
0answers
14 views

Why do PGP Keys have expiration dates? [duplicate]

I read a tutorial to get started with PGP and so far I understand the importance and the difference between encryption, decryption, signing, and verifying. However, I don't understand why a key has ...
1
vote
1answer
54 views

Necessary components for PGP [closed]

I came across this question during an interview. I was asked: What are the two main components of PGP encryption necessary for it to work? I was thinking in line of Private and Public Keys but I am ...
2
votes
2answers
170 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 ...
0
votes
1answer
16 views

Web of Trust: What is “signatory trust”?

I am learning about the Web of Trust and how to use it. However, I have some issues to fully grasp the concept of Signatory Trust. What is an easily understandable definition of signatory trust? An ...
4
votes
1answer
129 views

Help - Somebody stole my OpenPGP key ID, what can I do?

I received a key transition statement because somebody found himself in the exact same situation described here. This issue will target more and more OpenPGP users in future, probably even all of ...
5
votes
1answer
153 views

Should I sign the CAcert key?

Recently I got a CAcert Assurance and discovered that I can get my PGP key signed by CAcert key. After I got their signature, CAcert website suggested that I sign their key, too. Question: CAcert ...
3
votes
1answer
126 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 ...
2
votes
1answer
50 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 ...