Questions tagged [pgp]
The OpenPGP encrypted data format (RFC 4880), and its implementations PGP and GnuPG.
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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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Is compressing data prior to encryption necessary to reduce plaintext redundancy?
As explained in William Stallings' Book, in PGP encryption is done after compression, since it reduces redundancy.
I couldn't relate encryption strength with redundancy. Could anyone explain more on ...
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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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Is bcrypt better than GnuPG's iterated+salted hashing method?
GnuPG has slow hash built-in in form of iterated+salted S2K.
Does it have disadvantages in comparison with bcrypt or scrypt? Is GnuPG's slow hash method easily automated in GPUs?
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Is there an intuitive explanation as to why only the private key can decrypt a message encrypted with the public key?
I have just learned about using PGP/GPG for email encryption and one thing bugs me:
How is it possible that a message encrypted with somebody's public key can be decrypted only with that person's ...
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Alice trusts Bob only when Bob trusts Alice
some story first: Alice and Bob both have public/private key pairs. Now Bob wants Alice to sign his public key id. Alice agrees but only when Bob signs the public key id of her.
Is this something ...
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How does GPG verify succesful decryption?
How does GPG (or other programs using the OpenPGP file format) verify that it has succeeded with decryption (for symmetrically encrypted data)?
Is something appended to the clear text so there exist ...
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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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Why is padding the plaintext with a random string before encryption worse than OAEP / PKCS#7?
I'm reading about OAEP / PKCS padding used for PGP to turn deterministic algorithms like RSA from deterministic encryption to probabilistic encryption (randomness in the resulting output). That way ...
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PGP public RSA key format
I have been trying to use Go (I could post the code, but I think I posted enough already...) to generate a PGP RSA key. However every time I try to encrypt something with it, something fails. However, ...
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How does one verify a GPG/PGP key revocation?
After revoking a key and sending the revocation to MIT's keyserver, I noticed that the key is listed as such:
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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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How can I remove my personal data from my PGP public key?
According to this Q&A-discussion it is possible to remove all personal data (name and mail address) that is attached to a public key.
What steps do I have to follow in order to remove all ...
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Why is Curve25519 in the GPG “expert” options?
The only way to access the Curve25519 curve in GPG is through gpg --expert --full-gen-key.
From my knowledge, Curve25519 is one of the most secure (and fast) ...
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If PGP and GPG both follow the OpenPGP standard, are they 100% compatible in all use cases?
If someone gives me their PGP key, can I use it with GPG, and vice versa, all the time (100% interchangeable)? Or are there times when they are not compatible, when only PGP can be used with a PGP key,...
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Why is there the option to use NIST P-256 in GPG?
I am surely not an expert on the field, but I heard some people say that NIST P-256 somehow has backdoors.
I don't know about the seriousness of this claim; maybe it's just a conspiracy theory.
If ...
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Can I use PGP to sign a message without providing cryptographic non-repudation?
The difference between a digital signature and a MAC is non-repudiation. A message with a digital signature proves that only the sender could have signed the message, whereas a message with a MAC ...
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How to generate fingerprint for PGP public key
I would like to know how to generate a fingerprint for an openPGP public key.
To be clear, I'm interested in how the fingerprint is generated. I'm aware that I can get the fingerprint with a ...
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gpg --gen-random quality level: is higher "better"?
The GNU Privacy Guard manual pages have this to say about using the gpg --gen-random 0|1|2 count command:
Emit count random bytes of the given quality level 0, 1 ...
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Why the symmetric key layer in PGP?
I've been familiarizing myself with the basics of PGP. If I understand correctly, PGP symmetrically encrypts the data of interest using a random single-use key, then encrypts the encrypted data and ...
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What is the GnuPG process for going from a passphrase to a symmetric key?
Suppose I use GnuPG to symmetrically encrypt a file like so:
gpg --no-options -c --cipher-algo AES256 --no-random-seed-file -o my.out my.file
I then provide a ...
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Is there a "brainwallet" for GPG keys? [closed]
“Brainwallet” is a program that takes a passphrase (hopefully a good one) and deterministically creates a Bitcoin wallet. This wallet can be used for transactions, then deleted from the computer. To ...
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OpenPGP Public-Key algorithm
What means when pgpdump shows this kind of algorithm in the Public-Key Encrypted Session Key Packet?
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Is this a correctly formatted PGP session key packet?
RFC 4880 may be full of information, but it can be incredibly vague at times, so im looking for someone who actually knows the answer to this.
Given this public key:
...
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PGP String-to-Key specifiers
I've been reading through the PGP Standard and here I'm a little confused. This section is discussing converting string data to a session key. I'm confused about the paragraph in bold. First off, what ...
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How to properly format a PGP Message Block? [closed]
As sort of a follow up to my (currently) unanswered question, if it is correct, how do i properly calculate and format the packet that actually stores the data being encrypted? I thought I knew what I ...
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Is my identity exposed when publishing my public key or encrypting with PGP?
Let's say I create my PGP keys with my appropriate name and email address.
Will these personal information be exposed if I publish my public key?
When I encrypt a message for sending it to my ...
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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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If Bob steals Alice's private key, how exactly would he read her encrypted documents?
So Bob grabs Alice's secret key when she isn't looking and her encrypted files, doesn't he need to know her passphrase to read her files?
What I am reading is that no he does not need it but as far ...
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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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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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When is each key used when encrypting an email using OpenPGP?
When you send an email using PGP to encrypt emails, is the recipients public key used to encrypt the email, or is your private key used? Are they both used?
At what points do each of the four keys ...
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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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Primality test in GPG/RSA or extract numbers of private key
I cannot find if the two numbers for RSA are tested against an elliptic curve primality test. If not, is there a way to extract the two integers of my private key in order to test it by myself?
If ...
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How exactly would someone crack a private key passphrase? [closed]
Lets say for a PGP/GPG pair with a passphrase.
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