Questions tagged [pgp]

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

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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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167 views

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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232 views

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 to encrypt files such that only certain people (changing over time) can unencrypt and view the file?

I am setting up a platform whereby data is stored on IPFS and then give access to some (or in some cases all) through a front-end UI. Storing on IPFS is straight forward as is encrypting. First I ...
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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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Why is a PGP signed message structured the way it is? Historical background or standard?

I am pretty sure there's a good reason for this, but it just occurred to me I've been just taking for granted that all PGP signed messages look something like this: ...
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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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Brute-forcing a PGPDisk (.PGD) encrypted file

I have some ~20 year old PGPDisk (.PGD) files for which I have long since lost the keys and/or passwords. I've written some GPU accelerated brute-forcing for OpenOffice / PBKDF2 in the past, so I ...
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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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187 views

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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145 views

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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1answer
143 views

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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377 views

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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102 views

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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161 views

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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131 views

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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340 views

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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159 views

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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Creating nested messages in OpenPGP

I need to create a nested message in OpenPGP (my understanding is that the protocol itself should support it). Let's say I have Payload ("Time in Lordran is ...
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442 views

Computing PGP ed25519 and curve25519 keygrips?

There are public key algorithmic differences for how PGP computes fingerprints and keygrips. For the v4 protocol, fingerprints are not exclusively computed from public keys while keygrips are. RFC ...
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Assistance with parsing PGP PRIVATE KEY BLOCK's Secret-Key Packet (0x6) and Secret-Subkey Packet (0x7) using command lines and RFC 4880?

The throw away private keys below (master ed25519 & subkey curve 25519) were exported without being password encrypted. % cat skaht_0523F5B4_Secret.asc ...
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Is it possible in PGP to provide verification/verify the ownership of a public key?

I am new to PGP/GPG and I am somewhat confused by the idea of the Web of Trust (WoT). Isn't signing a public key with its private key enough to prove the ownership of it? if it is so, why don't key ...
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Safest method for encrypting a file on a local machine

I am looking for a safe method to encrypt a local file on my machine. Let's say I have a file containing my logins and passwords -- how can I make sure that the encryption is reasonably sufficient in ...
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Asymmetric algorithm with indefinite number of public keys

So RSA algorithm uses pre-generated set of public and private key, and public key is usually included in private key. So public key stays always the same. Is it theoretically possible to have some ...
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173 views

PGP double encrypt instead of signing?

So, maybe this is a dumb question, or maybe it's something someone's already done and it's really common, but whatever, here goes: Why do we sign a message with our private key and then encrypt it ...
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Decrypting an already sent encrypted file in PGP

I am a novice in cryptography and need few clarifications. If I am SenderA, sending document to Receiver using PGP encryption. Let's say, SenderA shuts down and SenderC takes on the role of SenderA. ...
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Message types in GPG

I am trying to check the part where messages are both encrypted and signed. But what is the difference between a message which looks like this ...
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What are some examples of out of bound channels that work over the Internet in practice?

If I want to verify a public key (be it RSA, PGP, etc.) with another client over the Internet only, what are some viable out-of-bound channels for verification? Which channels have been used in ...
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Possible to convert PGP ed25519 signature into signify-compatible format?

Both PGP and Signify (or Minisign) are capable of generating ED25519 detached signatures. Is it possible to convert a PGP-generated ED25519 signature into a signify-compatible format?
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Is encrypted e-mail sent over TLS 1.3 a form of “forward secrecy” (similar to something like Signal)?

One common complaint about GPG-encrypted e-mail is that it doesn't provide forward secrecy; however with opportunistic TLS becoming increasingly common in both IMAP and SMTP, it's not unreasonable to ...
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How does gpg know what cipher algorithm is needed for decryption?

I am using gpg to make encrypt a tar.gz. My first try uses --verbose --symmetric and then the decryption is done with ...
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119 views

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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123 views

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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542 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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