Tagged Questions
The OpenPGP encrypted data format (RFC 4880), and its implementations PGP and GnuPG.
22
votes
2answers
2k views
Why did TLS 1.3 prohibit PGP authentication?
There is a specification, in Informational(!) RFC 6091, for using PGP keys in TLS authentication, although I don’t think it has ever been implemented outside of GnuTLS (it’s certainly not in OpenSSL).
...
2
votes
1answer
58 views
Is it safe to publicly expose PBE-protected PGP secret keys?
I am working on a PGP scheme where a private key is created offline (and in volatile memory) and must be reused on very rare occasions to sign a piece of exportable data. The private key is locked ...
0
votes
0answers
11 views
Why does gnupg create 4 separate keys and what does sub and ssb mean?
When using gpg to create a single key, I get:
...
2
votes
0answers
27 views
GPG Sub Key Renewal Questions
Last year, I followed this guide to create two GnuPG Smart Cards; one card with the Primary Key and the other card with the Sub-keys.
I noticed that the sub keys were close to expiring so I renewed ...
-1
votes
1answer
32 views
Question About ECC Primitives (GnuPG)
In version 2.1, GnuPG featured primitives that use elliptic curves. For encryption, one option was ECDH, which confused me. I thought ECDH was for key agreement, not public key encryption. How does ...
7
votes
0answers
126 views
+100
What was the BassOmatic cipher, and what made it so weak?
According to Wikipedia, this homebrew cipher was originally used in PGP, before Phil Zimmermann replaced it with IDEA. Supposedly, insecurities in the algorithm were pointed out to him, leading to ...
2
votes
1answer
43 views
Revoke a GPG key using previously generated revoke certificate after renewd (change expiration date)
I have few sub-questions
Do secret keys get expired, or just the public key gets expired?
Do I have to back up the master sec key each time I renew it?
For an ...
0
votes
1answer
41 views
1
vote
0answers
24 views
GPG encrypt performance degradence for thousands receipients
I plan to use GPG to encrypt a small file (32KB) for very many recipient public keys (few thousands).
I tested GPG with RSA and then ECDH public key encryptions. If RSA is very slow, with ECDH (nist ...
5
votes
0answers
51 views
Why is recipient hashed in this Sign/Encrypt/Sign proposal?
Own research
In my journey into trying to understand PGP, and public key singing and encryption as a whole, I came across this answer on CE. It is an answer to a question with the title: Should we ...
50
votes
2answers
9k views
Is the software that uses PGP broken, or is it PGP itself?
PGP is all over the news (even on TV) and there seems to be a lot of confusion about it.
For the time being, people face articles like Attention PGP users: new vulnerabilities require you to take ...
4
votes
1answer
75 views
Where is Web of Trust being used?
I've been trying to find specific examples of where Web of Trust is being used today, but there seems to be little information about this. Are there any businesses using Web of Trust today? What do ...
0
votes
0answers
32 views
How can I encourage non-techie users to authenticate PGP-signed documents (with keys not at a keyserver)
How can I encourage non-techie users to authenticate PGP-signed documents by verifying 1) a PGP fingerprint published elsewhere against a PGP public key included in the document (and not at a key ...
0
votes
1answer
54 views
what is the difference of Pretty Good Privacy and Gnu Privacy Guard
i want to know about the difference. of this two. because as far as i know many cryptocurrency users. use this for more secure transactions specially when the amount is huge.. to prevent identity ...
1
vote
1answer
409 views
PGP Encryption and signing
There is a requirement for me to both encrypt a file with the clients public key provided to us and sign the same file with our (my own) private key which they have the corresponding public key for.
...
1
vote
1answer
36 views
Hash match vs PGP to ensure integrity
What is the difference? I found it quite hard to check for integrity using Gpg4win. Checking for hash was easy with Online MD5 & SHA1 Hash Generator For File. Is there any advantage to use Gpg4win?...
0
votes
1answer
35 views
GPG Details of Anatomy
What is the "created" field below? How can you translate that into an actual date?
Source: https://davesteele.github.io/gpg/2014/09/20/anatomy-of-a-gpg-key/
0
votes
0answers
92 views
GPG AES-256 Malleability
If Alice encrypts a file with GnuPG software using the AES-256 mode, and sends the encrypted file over an insecure channel (like E-mail or HTTP) to Bob. Both Alice and Bob know the password, but only ...
3
votes
1answer
120 views
Weaknesses in vanity PGP keys
The program Scallion can generate vanity PGP keys and .onion addresses using the following method:
Generate RSA key using OpenSSL on the CPU
Send the key to the GPU
Increase the key's public ...
0
votes
0answers
35 views
gpg --export-secret keys no passwd prompt [duplicate]
im running fedora 27 and gnupg version 1.4.22 and when I export my private key with
root# gpg --export-secret-keys --export-options export-reset-subkey-passwd
It ...
-1
votes
1answer
75 views
pgpdump alternative for gnupg 2.x
I want to see gpg2 key parameters packets. pgpdump v0.32 doesn't support gpg2 (especially elliptic curve cryptography packets) and "gpg2 --list-packets" doesn't show "secret" key parameters.
Is ...
3
votes
2answers
4k views
Why is there the option to use NIST P-256 in gnupg?
I am surely not an expert on the field , but I heared some people say that NIST P-256 is somehow backdoored .
I don't know about the seriousness of this claim . Maybes it is just some conspiracry ...
1
vote
1answer
149 views
Is it actually possible to secure data with gpg DSA keys?
I think GPG is difficult to understand . All the different versions and policies and algorythms . But today I got really confused . I tried to create a 3072 bit DSA key ( which as far as I undestand ...
7
votes
2answers
1k views
Why is c25519 in the GPG “expert” options?
The only way to access the c25519 curve in GPG is through gpg --expert --full-gen-key. Why is that? From my knowledge, Curve25519 is one of the most secure (and ...
-3
votes
1answer
59 views
Is OpenPGP used for purposes other than e-mail encryption and signing?
OpenPGP is generally used for encrypting and signing e-mails.
Are there any other use cases?
If yes, which cases?
5
votes
1answer
383 views
Is it possible to decrypt only a portion of a gpg encrypted file?
I have very large encrypted files that I need to process in a highly parallel fashion (the files are composed of distinct records of data). Currently, the process begins by first decrypting the data, ...
1
vote
1answer
561 views
What do GnuPG sign-only keys mean?
In GnuPG, there is the option of making keys which are "normal" (encrypt and sign) and sign-only keys . But what sense does that make in regards of DSA?
Correct me if I am wrong, but I think DSA keys ...
0
votes
1answer
90 views
What real life OpenPGP public key has the biggest amount of signatures on it? [closed]
Have you ever seen key with dozens or 100+ signatures? Link to it will be very much appreciated.
I have read that old Zimmermann's key had a lot of signatures on it, but I was not able to find it. In ...
1
vote
1answer
61 views
Is it possible to sign OpenPGP key without consent of a key owner? If yes, can unsolicited signatures be removed from a key?
For example, I have my key listed on a key server. On one day a key issued on the name of Julius Caesar signs my key. Obviously this key is a fake key and I want to remove its signature from my key ...
2
votes
0answers
57 views
How does OpenPGP handles situation when signatures on one OpenPGP key contradict each other?
For example, I was on a key signing party. After a party, one person signed my key with full trust and sent this signature to me by email. Then that person changed their mind and signed my key with ...
1
vote
1answer
336 views
Multiple signatures on one OpenPGP key. How are they combined? Where are they stored in OpenPGP certificate?
When one OpenPGP public key is signed multiple times by different keys, how these multiple signatures become visible on one OpenPGP certificate/key?
For example, I participated in a key signing party ...
-1
votes
1answer
57 views
What happens if you use a password longer then the hash of the KDF?
What happens if you use a password longer then the hash of the KDF?
For example in GPG symmetric a password which is 200 characters .
On AES-256 ( I don't know the maximum length of the KDF output).
2
votes
2answers
75 views
Can GnuPG be used with a login system?
I was thinking about creating a proof of concept for the following type of website login system.
Instead of passwords being used, on account creation, a public GnuPG key is uploaded to the server, ...
1
vote
1answer
228 views
What is the key derivation function used in GnuPG, and how long may its input be?
I am currently working with GnuPG on a new project of mine. It would be very useful to know two things for that, which are not described in the manual:
What is the maximum input size of a symmetric ...
3
votes
2answers
527 views
What exactly does s2k do in gpg
So I recently discovered the --s2k mode in gpg.
Sadly it is not very well-documented. I mean, what is ...
-1
votes
1answer
98 views
Using caesar crypt, then encrypting the output with pgp, then encrypting that with aes256
Is that possible? Well, of course it is, but if you decrypt it, will it show the actual message in the final output? This isn't me actually doing this in practice, just if it is possible.
Lets say ...
1
vote
3answers
830 views
PGP-key-based authentication system
Consider we implement remote service, which will be accessible via API(i.e. restful http or grpc). All users are authenticated via pgp keys and each user has pgp keypair.
How to implement ...
1
vote
2answers
1k views
How to create and send a symmetric key using GPG
I want to communicate with a friend (he lives in another country so we can't exchange fingerprints or keys physically, I could post him a USB disk but I'm sure I can do it through the web).
I'm ...
1
vote
1answer
278 views
Can the fingerprint of a PGP key be combined with a phone number?
Lets say I wanted to text a friend but I didn't want my carrier seeing my texts. I could just ask for a phone number, and have him/her text me a PGP public key. But, as everyone knows, the carrier can ...
3
votes
1answer
77 views
Service to expose all encrypted messages its users sent. How protected would this data be?
I have recently started a new side project for an open-source messaging system with end-to-end encryption.
My key idea with this project is that everything should be as transparent as possible, with ...
1
vote
0answers
471 views
How does GnuPG compress a file and how to deal with it? [closed]
When encrypting a file symmetrically with gpg -c file.txt, when and how does it compress the file?
I was working on a cryptopals challenge and wanted to test out ...
1
vote
0answers
53 views
PGP - MIME, is it correct?
I see following x.509 certificate attached(or may be signed, not sure) with OpenPGP key. Is that s/MIME certificate attached with PGP? What that does? Can this be created with GnuPG or probably, how ...
5
votes
1answer
185 views
Centralized storing of private RSA key
I working on multiuser project, where users can share data. The data that users upload to the server will be encrypted before it leaves the client with a symmetric cipher, and then the symmentric key ...
0
votes
1answer
62 views
Does keeping a PGP crypted message private helps?
In other words, if I make a PGP crypted message publicly available, do i compromise its security?
In other words which encryption level would guarantee me, say, 20 years of security?
Additionnally, ...
8
votes
2answers
3k views
Reverse engineering secret key in RSA encryption with the help of signature
Consider the following:
$i$th message, $m_i$, in its original state.
$i$th message, $M_i$, encrypted message $m_i$ using public key.
Public key, $p$, in a $b$-bit RSA encryption setup. We can ...
1
vote
0answers
597 views
GPG encryption truncates large files ( ~ 4 Gb ) [closed]
We currently use GPG to encrypt large text files ( ~ 4 Gb ) and occasionally the encrypted and compressed file will be truncated. I have tried several different algorithms but cannot pinpoint a ...
1
vote
1answer
3k views
Verifying a downloaded file with an .asc file
I downloaded CentOS 6.8 for 32-bit over torrent. It comes (among other things) with a sha256sum.txt file and a sha256sum.txt.asc file. I know how to verify the signature of a file when I have the ...
0
votes
1answer
200 views
What is standard email encryption practice?
So I've recently got an email client set up with an encryption plugin, but I'm not sure what's happening behind the scenes.
What I haven't been able to find anywhere online is what is the standard ...
5
votes
1answer
123 views
Are additional PGP subkeys still needed for smartcards?
After having purchased a USB GnuPG smartcard, I visited the manufacturer's website. A tutorial by the FSFE was mentioned there as the preferred way of setting up the smartcard.
However, this tutorial ...
5
votes
0answers
56 views
Can a PGP subordinate key be used as a web of trust signing key?
I already understand the desire to segregate a PGP master key from subkeys, allowing me to keep the master key in some off-site non-networked location while making use of the subkeys to do things like ...
