Tagged Questions

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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1answer
15 views

Use PGP/Mime with Thunderbird and Enigmail

I would like to sign all my mail with my PGP key, and no matter if the recipient uses PGP or not, it should not confuse them. Last week I read a discussion that inline PGP is not good pratice, and I ...
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2answers
33 views

GPG Web-of-Trust Level

(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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1answer
54 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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0answers
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How do I display the usage flags for my encryption keys in a less hackish way? [migrated]

I am trying to educate myself on the use of encryption keys and I've been experimenting with this old Linus Torvalds’ key that I found 956EB7BF449FA3AB. I am interested to display the usage flags but ...
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2answers
64 views

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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1answer
25 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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4answers
735 views

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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0answers
50 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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3answers
323 views

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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6answers
1k 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 ...
1
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1answer
55 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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2answers
85 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
64 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 ...
2
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1answer
61 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 ...
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1answer
45 views

Why should I separately backup my revoke certificate

So I understand the principles behind the concept of a revocation certificate and why it should be useful to create one and back up before harm occurs. The thing is, I don't see a wide range of media ...
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2answers
57 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 ...
2
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3answers
77 views

GPG keys & SHA-1

I've heard that SHA-1 hashing is becoming less secure, and that most GPG keys are secured with SHA-1. Is there a way to determined if SHA-1 is in my GPG key, and what to do if this is the case?
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2answers
103 views

Does adding multiple recipients to an encrypted message decrease security?

Let's say you want to send the same GPG/OpenPGP encrypted message to 50+ recipients. Assuming everyone you send to is trusted, and there is no risk of any recipient leaking their secret key, is ...
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2answers
164 views

How safe are signed git tags? Only as safe as SHA-1 or somehow safer?

How safe are signed git tags? Especially because git uses SHA-1. There is contradictory information around. So if one verifies a git tag (git tag -v tagname), then checksouts the tag, and checks that ...
2
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1answer
67 views

Which PGP settings have been found to be vulnerable?

Digging through articles, one often finds recommendations such as "Use the default key type/size X", whereas an article written a few years later will write "Key type/size X has been found to be ...
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1answer
72 views

GnuPG / OpenPGP: How to eliminate redundancy in PGP private key?

I examined a few randomly generated private keys generated by Gnu PG, and found a lot of redundancy. It is enclosed by -----BEGIN PGP PRIVATE KEY BLOCK----- and -----END PGP PRIVATE KEY BLOCK----- ...
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1answer
40 views

What happens if my signing subkeys are compromised?

Let's say my subkeys are compromised, but my master keypair is safe and secure, so I revoke the old subkeys and issue new ones. With encryption keys, the results are pretty clear: I can still decrypt ...
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1answer
58 views

How long do keys stay on keyservers?

Do GPG/PGP keyservers "garbage collect" old keys which have expired, been revoked, or simply haven't been updated in a decade? Or does the server (theoretically) keep every key it has ever seen from ...
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3answers
93 views

What are you saying when you sign a PGP key?

When you sign a PGP/GPG key, what exactly are you saying to everyone who sees your signature? Are you validating the person, or the email address? To explain what I mean, take the following two ...
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3answers
84 views

Best practices for GPG user ids

What is the best practice for choosing GPG user id(s)? I've read various bits of advice, which sometimes even contradict each other. For instance, I've read that one should not use comments, because ...
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1answer
46 views

Replacing subkeys.

Here's a specific scenario that I have. I want to have subkeys on my laptop and store the master key safely. So I went ahead and created new keys: gpg --gen-key gpg (GnuPG/MacGPG2) 2.0.20; ...
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2answers
52 views

Can I generate multiple PGP key pairs for later use

I was just wondering if I can generate couple of PGP key pairs and save them for later use or backup. In addition can I be sure that other wont generate and use some of my key pairs in the meantime. I ...
2
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2answers
46 views

Can the GPG master secret key be stored as read-only?

Once you have generated your master PGP key, will the "data" in the private key ever change? For instance, if you add another subkey, uid, or any other data to the master key, do these changes need ...
2
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2answers
120 views

How to Conceal/Detect PGP Symmetric Algorithm Used

When Symmetrically encrypting a file, (not signing, not an asymmetric encryption question), is it possible to conceal the encryption algorithm used, or is it already concealed, but just showing on ...
3
votes
3answers
114 views

How do I ensure that my Ubuntu download has not been tampered with?

I am downloading Ubuntu Linux, and would like to make sure that my download has not been tampered with. Ubuntu has a GPG key, which I could use to make sure that the download is valid -- but how do I ...
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2answers
50 views

Attaching the same file to two separate email, does it compromise security of the “message”

When using (Thunderbird and) GnuPG to send a PGP/MIME message to two separate recipients, with the text body different in both messages, but the same file attached to both of them, does this give an ...
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1answer
63 views

GPG encryption and signing

Why don't the commands gpg2 --armor --sign file.txt and gpg2 --clearsign file.txt have the same output? Also when I use just --sign I get a bunch of binary gibberish surrounding the message in ...
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1answer
45 views

Security of sending information to stdout

By default, something like gpg -d file.gpg sends it's output to stdout. What happens to input that is sent to stdout? Is it possible to recover this?
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1answer
92 views

Linux SSH and GPG

Can anyone please give me a quick crash course on SSH and GPG? SSH: What is the difference between public and private keys? Should I back up my ~/.ssh/ directory, what are the security implications ...
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votes
2answers
144 views

PGP/GPG verifying authenticity

My boss recently implemented a new security system related to PGP/GPG. The whole idea behind this is to sign files so that people know from who they came. They don't require us to encrypt them, just ...
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1answer
114 views

How secure is GPG symmetric encryption?

Since I am new to encryption and have recently been losing stuff, I decided to start a file that contains some passwords for online accounts and whatnot, encrypt it, back it up (and keep a single copy ...
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0answers
38 views

Converting PGP2.x UIDs on a GPG key

I have a couple of keys which were created many years ago, before GPG came out. (But let's pretend there's only one key involved.) The key has a mix of GPG and PGP-2.x-style UIDs. I've made one of ...
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3answers
84 views

What is the technical rationale behind intermediary email servers?

EFF's Survelliance Self-Defense (SSD) project has an illustration of how email over SMTP goes through intermediate mail exchange servers: AFAIK each intermediate servers is expected to add its own ...
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1answer
129 views

GPG Different Passphrase for Subkey

Is it possible to have a different passphrase for a GPG subkey? The reason is that I'm using duplicity to back up my files, and it needs the key passphrase to sign the files. Since I want run ...
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0answers
58 views

Fastest public-key algorithm for testing purposes

As part of an automated test suite I need to run a lot of gpg --encrypt and gpg --decript processes. In order to make each invocation of gpg --encrypt and gpg --decrypt will be faster, I would like ...
3
votes
1answer
62 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 ...
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1answer
87 views

Recommended operational security for generating one's primary key pair?

I have been looking for an operational security guide for generating one's asymmetric key pair for (Open)PGP. I have found plenty of technical guides for how to use GnuPG to generate RSA key-pairs, ...
3
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1answer
68 views

Utility of multiple signing subkeys when we're restricted to a single encryption subkey in GnuPG (PGP)

As I understand it, GnuPG allows the creation of multiple subkeys, but multiple encryption subkeys are problematic because it's not clear which encryption subkey someone should use when sending a ...
3
votes
1answer
73 views

Can I reencrypt my GPG private key with more password rounds?

As noted elsewhere, SSH private keys can be reencrypted (in different formats) with more rounds of iteration in the password-derivation function. Is there a way to do something similar for an already ...
2
votes
1answer
136 views

How are PGP/GPG private keys stored?

The default format in which SSH private keys are stored is notably fairly insecure against bruteforce attacks. This question provides a very nice solution to the problem by encrypting SSH private keys ...
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1answer
719 views

Why is GPG file encryption so much slower than other AES implementations?

Correct me if I'm wrong: When encrypting a file, GPG creates a one-off AES encryption key and encrypts that key using RSA. This is supposedly to take advantage of AES's superior performance when ...
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2answers
272 views

When using PGP/GPG, is it safe to use the same public/private key pair on multiple computers for the same person?

It seems somewhat unsafe to move the private portion of one's key around to multiple machines...but it also seems odd to have multiple identities floating around.
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0answers
88 views

Location of passphrase digest in opengpg secring.gpg

I'm trying to understand the file format of the secring.gpg file. I couldn't really find any official documentation of the file format so I decided to create a new key-pair and use the S2K ...
0
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1answer
107 views

how to verify file signature by client PGP

Currently working on verifying and signing a file via GNUPG, given that I've already signed a file, given the clients the .sig and public key, is there a way for a client to verify the file without ...
2
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3answers
212 views

OpenPGP Master Key Size

Currently the default maximum key size is 4096. I know this can be changed by recompiling the software, and I don't mind doing that. My problem is about compatibility issues. It makes sense that some ...