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Questions tagged [public-key-encryption]

Public-key cryptography (encryption is a misnomer) is the process of creating two keys during the encryption of plain text, one private and one public.

112 questions
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Can you extend the expiration date of an already expired GPG key?

Lets say I add an expiration date to a GPG/PGP key, then for some reason am unable to extend the expiration date of the key before its time is up. Assuming I still have access to the private key (and the public key has only expired, not been…
IQAndreas
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How can I use encryption with Gmail?

I'm currently reading Cory Doctorow's novel Little Brother which includes a part about encrypted messaging, and even wrapping messages first in my private key and then your public key. I'd like to play around with that but from what I've googled so…
Torben Gundtofte-Bruun
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Does the right half of the rsa public key matter?

In a public key file "id_rsa.pub" generated by ssh-keygen, does the part after the == matter? I ask because when I changed "root@somedomain.com" to "root", it seems to still work. More generally, I am curious about what the purpose of that half is.
merlin2011
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Can I change the filename of my ssh public/private key pair?

I created a public/private key pair: ssh-keygen -t rsa -C "me@example.com" I gave a different key file name than id_rsa since I wanted to create a new separate key from my normal identity. I gave this key to my hosting provider so that I can login…
jjeaton
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5 answers

How does SSH encryption work?

I've read about generating 2 keys (private and public) on client host and copying the public key to the server host. As I understand it, (correct me if i'm wrong): The server encrypts data with the public key and sends it to client, the client…
DrStrangeLove
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Human-readable dump of gpg public key

Is there some tool to write out the actual content of a GnuPG public key in a way a human can unserstand? I mean not only ascii-armor which a human can read and type, but something which really breaks down the data into large decimal numbers for the…
MvG
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Why does GPG/PGP by default use different keys for signing/encryption?

If you create a new GPG key, you'll by default get a signing-only master key pair and an encryption-only sub-key pair. pub 2048R/XXXXXXXX created: 2013-02-09 expires: 2014-02-09 usage: SC sec 2048R/XXXXXXXX 2013-02-09 [expires:…
Chaos_99
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4 answers

How to check if a GPG encrypted file is encrypted using a specific public key?

Consider if a file is encrypted using command e.g. gpg --output test.txt.gpg --encrypt --recipient test@example.com test.txt Now, consider another person received test.txt.gpg the the pub key test@example.com, how to perform a check to make sure…
Yoga
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I got "BEGIN PGP PUBLIC KEY BLOCK" attached to an email and I don't know what it is

Okay, I have no clue what this is, but I just received an email that has this in it. -----BEGIN PGP PUBLIC KEY BLOCK----- [redacted] -----END PGP PUBLIC KEY BLOCK----- If this means something, could someone decode it for me? If not, then could…
user958945
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How do I use the openssl command to decode a certificate/public key .PEM file?

I have my localhost TSL/SSL certificate from Chrome stored to a .PEM file. Was wondering how do I use the oppenssl command to decode it into a list of human-readable fields. Googling this only returned info on how to work with the private…
Daniel Donnelly
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How, if at all, do SSH keys differ from asymmetric keys used for other purposes?

How, if at all, do SSH keys differ from asymmetric keys used for other purposes, e.g. email signing? I'm prompted to ask this, in part, because on OS X, there are apps available to manage SSH keys (ssh-agent, SSHKeychain, etc) as well as apps…
user11574
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2 answers

How are public keys "sent" to servers, and how are private keys "used" for SSH?

There are two Linux machines, A and B. Scripts running on A need to be able to SSH into B. So A generates a public key (probably an ssh-keygen-generated id_rsa.pub), and then uses its respective private key (again, probably id_rsa) to make that SSH…
user3178622
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Isn't it dangerous to use SSH keys to login to an unknown/compromised server?

Say I provide someone with my public SSH key, the id_rsa.pub and he/she installs it on a server that is compromised, and I am asked to login. Does the login process involve sending my private key to the compromised server? If yes, then the attacker…
Gurjeet Singh
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How to generate a public/private key (UNIX)

Can some one please tell me, for using SSH, why does a host also need to have a public and private key? And how can I generate a public/private key pair for myself?
Justin k
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How can I use GnuPG with ECDSA keys?

I'd like to generate an ECDSA (rather than RSA, DSA, or ElGamal) key using GnuPG, and use it as I might otherwise use an OpenPGP-compatible master key. I've read that gpg2has support for ECDSA keys, but I haven't been able to use that functionality.…
flamsmark
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