Questions tagged [pgp]
The OpenPGP encrypted data format (RFC 4880), and its implementations PGP and GnuPG.
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Decrypt a file that has been encrypted using libgcrypt library
I encrypted a text using libgcrypt with AES256 CFB and saved it in a file. Why can't I decrypt the file on command line with gpg -d ?
I can decrypt the file using libgcrypt.
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2answers
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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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1answer
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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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1answer
44 views
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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1answer
23 views
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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0answers
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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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4answers
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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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1answer
66 views
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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1answer
66 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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2answers
106 views
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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1answer
42 views
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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0answers
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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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1answer
14 views
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
87 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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1answer
217 views
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
46 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
25 views
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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1answer
50 views
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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2answers
47 views
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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1answer
47 views
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
291 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
59 views
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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1answer
673 views
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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1answer
183 views
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
2k 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*
Can ...
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0answers
62 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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1answer
69 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
158 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
55 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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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
108 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
272 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
41 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
106 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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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
175 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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1answer
125 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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2answers
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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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1answer
138 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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1answer
64 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
1k 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
100 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
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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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1answer
264 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
1k views
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 (...
