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Questions tagged [pgp]

The OpenPGP encrypted data format (RFC 4880), and its implementations PGP and GnuPG.

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libsodium vs gnupg curve25519 compatibility

I am trying to create deterministic GPG keys based on cryptosteel. I have implemented a library for (de)serializing PGP packets and am now trying to use keys generated in libsodium for import in GPG. ...
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1answer
56 views

How Secure is gpg Command Using Symmetric AES-256 From Being Cracked

How secure is any data encrypted using the following command: gpg -o *encrypted_output_file_name* --symmetric --cipher-algo AES256 *file_to_be_encrypted* ...
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57 views

Concept for a RSA “repeater”. Is it sensible?

I have been using RSA signed/encrypted mailing a lot recently. Naturally, I wanted to use RSA mailing also on my phone, not only on my computer. However, I feel uneasy having my private key on my ...
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Trying to verify a download signature with PGP, but getting “no signed data” when passing in the .asc file? [migrated]

I tried the following steps from Verifying Signatures on the Tor Project: gpg.exe --keyserver pool.sks-keyservers.net --recv-keys 0x4E2C6E8793298290 imported: 1 ...
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1answer
55 views

Pseudonymous publication of a series of texts online when a bad guy is expected to join in with fakes: will this approach to PGP verifiability work?

Alice wishes to publish under a pseudonym a series of texts online. She expects the texts to circulate, and she will not include any way of contacting her. Bob will not know the identity of the ...
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1answer
56 views

Format of hybrid crypto envelope structure?

From posts including the accepted answer to How to encrypt file with RSA and AES that anyone with RSA key can decrypt them? hybrid crypto (AKA envelope encryption) a GPG-encrypted file has an ...
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1answer
45 views

Send content to owner of gpg public key, nested content symmetric encryption

If I want to encrypt a text content file using a symmetric algorithm like AES, is there a standard format gpg will expect, where it can detect a symmetric key (encrypted with recipient gpg public key ...
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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). ...
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1answer
80 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 ...
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1answer
52 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: ...
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0answers
28 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 ...
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1answer
47 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 ...
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162 views

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
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1answer
57 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 ...
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1answer
48 views

Understanding certificates for public keys with subkey

I have a openpgp key with 3 subkeys: ...
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0answers
32 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 ...
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0answers
58 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 ...
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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 ...
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1answer
79 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 ...
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34 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 ...
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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 ...
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1answer
574 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. ...
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1answer
46 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?...
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1answer
41 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/
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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 ...
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1answer
143 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 ...
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1answer
91 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 ...
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2answers
5k 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 ...
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1answer
170 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 ...
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2answers
2k 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 ...
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1answer
64 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?
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1answer
411 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, ...
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1answer
661 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 ...
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94 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 ...
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1answer
63 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 ...
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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 ...
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1answer
397 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 ...
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1answer
62 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).
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2answers
79 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, ...
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1answer
270 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 ...
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2answers
666 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 ...
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1answer
105 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 ...
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3answers
997 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 ...
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2answers
2k 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 ...
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1answer
283 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
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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 ...
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0answers
555 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 ...
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0answers
54 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 ...
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1answer
191 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 ...
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1answer
63 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, ...