Questions tagged [pgp]

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

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Is the signature in PGP compressed as well, or just the contents of the message?

I am developing an implementation of OpenPGP, and I'm using Kleopatra to test my generated messages. After generating a signature for a message, I compress both the message and signature, but upon ...
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GnuPG - provide encryption key for AES rather than deriving it from passphrase

I'd like to encrypt a file with AES256 and provide my own 32-bytes for the encryption, rather than having GPG derive it from the passphrase. I could not find such option, but I'm thinking about a ...
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What, if any, are the IETF namespace notations for OpenPGP signatures?

RFC 4880 section 5.2.3.16, "Notation Data," describes how arbitrary additional notations in the form of name-value pairs can be included in an OpenPGP signature packet. Regarding names, it ...
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Can you derive the public key from a PGP encrypted message without knowing the message content?

I am working on a system to transfer short messages while obfuscating the intended recipient. In essence, it combines many messages encrypted using PGP, and periodically publishes a file containing ...
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Only DRBG is used for PGP or could use other PRNG?

-RFC4880 refer to DRBG at https://www.rfc-editor.org/rfc/rfc4880#section-16.2 -Could we apply other PRNG such as enocoro/photon for pgp?
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MAC vs MDC when using ECDH+ECDSA in OpenPGP

I intend to design a model to comply with RFC4880. According to RFC6637, ECC in OpenPGP +ECDSA to sign message +ECDH + KeyWrap for session key encryption -MAC: is used for key confirmation (with C(1e, ...
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Is it possible to use PGP subkeys in multiple emails without correlating them?

I would like to know if sub-public keys of PGP keys can be published separately, if I create a pair of master keys and multiple sub keys to be used in multiple emails, and normally use only the sub ...
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Web of trust assigning level of trust to someone's public key without directly signing it's key

Having this web of trust scheme, I have a question concerning third scenario in which we assign Dharma and Chloe a marginal trust. In case of Dharma the situation is clear, we sign her public key and ...
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RSA Encryption and ECDH in OpenPGP

According to RFC4880 standard 1.Refer to section 2.1 Confidentiality via Encryption --> OpenPGP combines symmetric-key encryption and public-key encryption to provide confidentiality +To protect ...
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gpg symmetric encryption decrypts without asking for the symmetric key when --decrypt option is used

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Is gpg -c safe if an attacker can see multiple versions of a file?

Let's say I have a text file, and I modify it slightly 20 times, and I encrypt each modification using gpg -c (with the same 20 chars secure password). If the attacker has access to the 20 encrypted ...
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Can other modes be applied in OpenPGP (not using CFB mode)?

According to https://www.rfc-editor.org/rfc/rfc4880.html#section-13.9 -> OpenPGP only mentioned about CFB mode. According to https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-...
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How do you get a Public Key from a Fingerprint

I've seen some people putting their public key's (I'd suppose they refer to a PGP PK) fingerprint on powerpoints and alike so that they can be reached out to using a safe channel. From my POV, it's ...
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DKIM &PGP email security

I'm trying to figure out when using DKIM it signs all of the email including the body message and the from address , and with pgp it uses a unique key while in dkim is a general key ... but with both ...
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Are PGP messages susceptible to man-in-the-middle attack?

Say Alice wants to send a PGP encrypted message to Bob. She generates a symmetric key, encrypts it with Bob's public key, and sends both the message and the encrypted symmetric key to Bob. Then Bob is ...
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Which elliptic curve was used by Thunderbird OpenPGP and which bitlength?

If one looks at Account Settings > End-to-End-Encryption > Add Key and creates a new key then gets the option EC. But you can't choose the bit length nor does ...
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Pretty much confused about pretty good privacy-:

Authentication-: I understand that authentication is basically digital signature. But what I don't understand is how it has been explained here specially the RSA key part. It is leading me to huge ...
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Why do people use protocols like PGP, when TLS already exists?

TLS is the standard cryptography protocol on the internet, and many websites use it to secure their communications. However, for personal use, most people use other protocols like PGP, instead of ...
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Can I use SHA256 from BIP39 passphrase for auth credentials?

I am working on an E2E encrypted app. I am using OpenPGP.js and storing public and private keys on the server. The private key is encrypted with a BIP39 passphrase which is stored in browser ...
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Multiuser encryption, singleuser decryption [duplicate]

I have an hybrid encryption (RSA, AES) for a file sharing project I am working on, where I use a single public key for encryption on the sender side and corresponding private key for decryption on the ...
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Should strong RSA key with SHA1 self-signature in public key to be considered weak?

Older RSA-4096 GPG keys generated when SHA1 still thought to be acceptable have public key self-signed with SHA1. Shall this considered to be weak key? And with what arguments? AFAIK, GPG key ids are ...
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Saving highly sensitive data in US cloud - what encryption would you use?

We have a cloud-based application running on AWS servers and are looking for a way to store highly sensitive user data there without giving AWS the possibility of exposing our data to the US ...
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Why are NIST curves still used?

I'm relatively new to the world of crypto (But as far as the math goes, I am familiar with the inner workings. I used to rarely use it for privacy, but now I use it for many things). Anyway, I was ...
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643 views

Why use ASCII armor for file encryption?

GPG and age both offer a --armor option but what is the use case when it comes to file encryption? Surely most channels allow for transmitting binary data nowadays? ...
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How many encryptions are needed before OpenPGP key privacy is violated?

According to an excellent answer describing the pitfalls of key privacy in OpenPGP: Theoretically, an all-zero key ID can be used as a way to discourage traffic analysis, but this is not a complete ...
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PGP files included on email [closed]

I just got an email from a professor that included two files, with no clues about them in the message. The files are named OpenPGP_...EA.asc and OpenPGP_signature. I figured, since I asked some stuff ...
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Add setup to GPG symmetric

I use GPG symmetric, to encrypt text file. Is it possible to use GPG symmetric, to encrypt a text file, and at the same time, add additional setting to the encrypted file, to give us 2 conditions: ...
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PGP file size limit for encryption

Unsure it's the best place to ask, anyway: I know symmetric encryption is the best for such tasks but I am planning to encrypt large backup files (between 10 and 100GB) with my private PGP key. My ...
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Why does PGP still use the Fermat primality test? What if it hits one of the Carmichael numbers?

Since the Fermat primality test is not very reliable, most applications use it for pretesting only. Wikipedia says that PGP still uses it: Another well known program that relies only on the Fermat ...
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Is GPG symmetric encryption only based on a passphrase?

Is the symmetric key derived for AES only dependent on the passphrase? Is it possible to generate the encryption key such that it is based on my primary GPG private key and temporary passphrase? In ...
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How is the session key more secure than the public key?

From the website of GNU Privacy Guard (GnuPG): If an attacker could decrypt a session key it would only be useful for reading the one message encrypted with that session key. The attacker would have ...
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PGP private key format

I have a PGP Private Key from Bob. ...
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GPG should you double sign?

This is not a question about whether I should encrypt or sign first, as I've read here. Rather, it's about whether I should sign, then encrypt, then sign again. Because as far as I know, there is no ...
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How to correctly (good practice) generate gpg keys in batch mode (unattended) WITH a passphrase

I'm writing a web interface in PHP to generate keys. I'm familiar with gpg's command line options, particularly --batch. I'm also familiar with PHP's GnuPG API. I can't find a way to safely pass the ...
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PGP signature on literal data packet

I read from PGP spec RFC 1991, section 6.1 (August 1996): The exclusion of the other fields ensures that detached signatures are exactly the same as attached signatures prefixed to the message. ...
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Can there be different representation of the same public PGP key?

I have two PGP public key files: File1 was created with Kleopatra / Gpg4win. File2 was created by the following procedure: Import File1 as public key for EmailAccount1 into Thunderbird 78.4.0 Send ...
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GPG + OTP--Would that be authenticated encryption?

Here is a GPG message, signed and encrypted (strictly for demonstration, with test keys): ...
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Authenticated, Quantum-resistant GPG2?

GPG2 does not provide authentication. It still uses SHA-1 by default. It does not seem to get any stronger as time goes by. If one were to pass a randomly-generated symmetric key (from a TRNG) over ...
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Signing a GPG Public Key

I am trying to manually create a GPG Public Key (see here). I am able to generate a GPG Public Key with a correct hash, but fail to RSA-sign that hash in a way that is accepted by the GPG CLI. For the ...
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Is it possible to get the PGP public key from PGP message?

Is it possible to get the public key from PGP message in PEM(Base64) format? Here is the message: ...
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1 answer
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Manually creating a GPG Public Key

I want to manually create a GPG public key that can be imported into GPG, i.e. I want to create a file with a Public-Key Packet, a User ID Packet and a Signature Packet (for an example see here). I ...
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Why is GnuPG changing first two characters of ascii armored public key after downloading it from the key server?

When I look at my public key on the key server, the first two characters of the ASCII-Armored data section (as defined in section 6.2 of RFC 4880, which defines the structure of the ASCII-Armored ...
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What is the PGP Web of Trust Strongset?

I understand that it is a system that "establishes the authenticity of the binding between public keys and their owners", but how does one join this web of trust? Do you have to physically meet one of ...
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Encrypt text message with Wireguard public key

With its public and private key(s), Wireguard looks a bit like PGP. But it is used for encryption of network packets and not normal text messages. I'm on a system with Wireguard already installed and ...
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What prevents ProtonMail from sending me the wrong public keys?

I've recently been looking at ProtonMail, an email service which provides transparent end to end encryption between users with PGP. In order for the encryption to be transparent, ProtonMail manages ...
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Is it possible to verify a clearsigned message with a short public key (fingerprints)?

For practical reasons, I'd like people to be able to post clearsigned messages with their public key fingerprints (8E570D9F7F70256595769E49F9BC5BCAD7E18635) for the ...
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What does Modification Detection Code (MDC) in OpenPGP do?

The authentication is often done by an HMAC in modern cryptosystems. What does MDC do exactly in OpenPGP and is it a software hack or an algorithmic authentication? Also, how to force GnuPG to stop ...
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why Efail CFB malleability gadget is different from CFB mode decryption?

Really, I could not understand why the decryption process of CFB malleability gadget takes the next cipher block while PGP uses the previous block as shown in the equations in the attached image, I ...
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1 answer
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Testing speed of symmetric vs asymmetric encryption and decryption using gpg

I'm aware that symmetric is faster than asymmetric. I want to test this, but my (obviously incorrect) tests show the reverse. Symmetric test: ...
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Encrypt symmetric session key with asymmetric or symmetric master key?

Every day, I must backup my server's files, encrypt the backup, and upload it to untrusted cloud storage (dropbox, s3, etc.) I've spent time on security.stackexchange where I discovered the typical ...
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