Questions tagged [pgp]

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

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Is this PGP key exchange secure?

I am currently trying to create a secure key exchange between two parties. I have a good implementation of PGP that works well for my app, but my DH is really slow and doesn't work well; so I was ...
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Is there a human readable easier version to represent PGP Private keys?

I'm working on a distributed application, and we need a way to authorize clients. Every client has a PGP keypair associated with them, and we require them to enter their private key (which is not ...
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What is a nested signature in GPG and how to decrypt it in OpenPGP?

When I decrypt a file in OpenPGP (in Golang), I receive this error message: unsupported feature: nested signatures There is very little clear information about ...
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Do people sign my subkey?

So, I've generated my GPG key pair. Created a subkey for signing and a subkey for encryption. Exported the whole thing, removed my master key pair to a secure place, re-imported only the subkeys. Now, ...
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Why do I want to use PGP subkeys?

I understand the general notion in play: if my laptop/computer is stolen or compromised I can revoke that particular subkey so (as long as people have updated their keys) they can't impersonate me. ...
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GPG implementation of ECC “Encryption” (ECDH) vs RSA

My understanding of GPG with traditional RSA keys, is that RSA is by definition can be used to both sign and encrypt. This is because RSA can be directly applied to plaintext in the following form: <...
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How to let CA signed x509 key work in OpenPGP mailing system?

So let's say we have a OpenPGP mailing system which all mails are signed and encrypted with OpenPGP keys. And now you bought a CA signed x509 certificate and you want to imement into the mailing ...
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1answer
54 views

Should I PGP encrypt using a publickey intended only for Certify?

I'm working with a publickey that does not include EncryptStorage or EncryptCommunication flags (see RFC4880 for flag reference). My question is, is it safe/appropriate to encrypt using this key? <...
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In GnuPG, what's the difference between --s2k-cipher-algo and --cipher-algo? [duplicate]

I want to change some encryption options while using GnuPG to encrypt a file symmetrically. 1) However, for choosing the cipher algorithm, GnuPG has two commands and I don't know which one to use. ...
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1answer
44 views

About the security of GnuPG private key on-disk storage

GnuPG on-disk storage of secret key material is encrypted with AES-128, with an encryption key generated via an iterated and salted SHA-1 hash of the given passphrase. Is this usage of the SHA-1 hash ...
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1answer
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Converting a message from one PGP key to another PGP key

I have a message $M$ that is encrypted using a public key $P_1$. I lost the associated private key $p_1$. I have another public/private key pair $(P_2, p_2)$. Is it possible to "translate" the ...
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Book request about elliptic curves, RSA and DSA

I understand that this question can be hardly downvoted, but so be it if someone gives me really useful references :) I wanna learn difference (deeply) between RSA, DSA, and ECC, especially I am ...
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Mathematical explaination of file encryption for multiple persons with multiple keys

Let's say I want to encrypt a document which only can be read by John, Mike, and Dave. This can easily done with PGP/GPG: Import John‘s, Mike‘s, and Dave's public key Encrypt the document using those ...
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Where can I find the standard definition for GPG ECDSA signature?

I am playing around with GPG which I'd like to use to sign an integer and use the resulting signature binary in another piece of code. So far I have created a simple PGP packet parser with which I ...
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2answers
246 views

Generate PGP keys very very fast

Is there a way to generate thousands of PGP keys at a very very fast rate? I am generating thousands of 3072-bit PGP keys looking like part of a personal research project. Obviously, this is a very ...
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1answer
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Is there any point to encrypting a file if it's transferred via ssh?

Suppose I have two machines which can ssh into each other. Is there very little point in using gpg with a password protected symmetric cipher to transfer a ...
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Do PGP keys with expiration date set expiration date in Encrypted messages too?

So I am little confused about a type of encryption I read about. You can encrypt your E-mails and pretty much all kind of information using PGP key pairs. However, I am confused if an encrypted ...
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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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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* Can ...
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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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1answer
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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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147 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
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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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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
105 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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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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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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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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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 ...
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1answer
149 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
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Understanding certificates for public keys with subkey

I have a openpgp key with 3 subkeys: ...
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1answer
111 views

GPG encrypt performance degradence for thousands receipients [closed]

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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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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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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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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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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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
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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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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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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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AES 128 GCM - dynamic key with static IV/nonce

I'm working on a project to upgrade an existing system that currently uses RC4 to encrypt a payload with a random session key. The session key is then encrypted with asymmetric public key encryption (...
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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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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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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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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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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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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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980 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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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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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 ...