Questions tagged [key-authentication]

Questions pertaining to key authentication, a type of authentication that may be used as an alternative to password authentication. Instead of requiring a user's password, it is possible to confirm the client's identity by using asymmetric cryptography algorithms, with public and private keys.

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Is there a script to query multiple key servers to confirm a gpg public key?

I'm trying to verify the checksums of a linux distribution. These come with a signed file for verification. Unfortunately, since the signature for import into the keyring comes from the same site that ...
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receiving GPG error while using sudo apt update in Pop!_OS 22.04

I ran this command in Terminal: sudo apt update At the end I received this message: W: An error occurred during the signature verification. The repository is not updated and the previous index files ...
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disable ssh public key auth when user is expired

Environment is Ubuntu Bionic LTS, I have local user account which is expired, i.e. # chage -l user-test Last password change : Apr 28, 2021 Password expires : ...
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3 answers
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Where is the undo button in Linux? If I created an SSH key and copied the public key to a NAS, how would I undo or delete it?

I created an SSH key using ssh-keygen -t rsa. Then I copied the key to the NAS, so I wouldn't have to enter a password using ssh-copy-id. I realized that I did it for the wrong user, so now I need to ...
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Read key properties

I have multiple keys (some private, some public) and I want to get information about them (their length, their type, anything else). Is that possible?
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Sftp passwordless systemctl ask for password , but /etc/sbin/sshd -d not

I have two environments a Qual and a Prod environments. I am trying to setup a passwordless connexion with usernologin. Everything is working well on the Qual environment. Permissions on .ssh ...
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For OpenSSH legacy hardware access, ssh-rsa is used as preferred host key algorithm only if -oHostkeyAlgorithms=+ssh-rsa is included on command line

The connection is for WD MyCloud [OS3], local network only as cloud access has been closed. Sshd_config contains: HostKeyAlgorithms=ssh-rsa,ssh-rsa-cert-v01@openssh.com PubkeyAcceptedAlgorithms=+ssh-...
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Access to Linux server still requires password after setup authorized_keys

I have both manually set up the authorized_keys and using ssh-copy-id, but it still requires the password. I have made sure my home directory has 755, the .ssh has 700 and authorized_keys has 600 Here ...
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Using SSH Git: key lost after system restart?

I am setting up Git usage on Raspbian. This worked OK: cd .ssh ssh-keygen -t rsa -b 4096 -C "name@asdf.com" eval $(ssh-agent -s) ssh-add ./id_rsa_rpi After I created the keys ...
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private key ssh - ssh as another user

I am usera, I want to ssh userb@remote_ubuntu. so I copied usera authorized_keys to userb .ssh directory and renamed it id_rsa.usera (there is already a authorized_keys file there for when userb is ...
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2 answers
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SSH to a private VM with key authentication

I am new to Linux and this is my first time connecting to a private VM. I was given a private address(no public since the file not does not have ".pud") I am not sure how to use the given ...
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What can a id_rsa.pub file be used for?

What can the id_rsa.pub file be used for? I am working in machine A. I need to have an account in machine B. Another user from my team asked me for my id_rsa.pub (from machine A I suppose) so that he ...
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Sharing ssh keys between cluster nodes

I have a cluster with several login nodes and many compute nodes (call it the cluster). Then I have another server with a large shared storage (call it the storage). I need to be able to rsync (i.e. ...
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Why am I able to SSH a remote machine even with the wrong keys?

Description I have created an ssh connection between my MS-Windows PC and Raspberry Pi. To do so I followed the following steps: Step 1: Somehow get the IP address of the Raspberry Pi. It should be ...
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SSH could not find hidden user folder

I generated a public/private rsa key pair to access the remote host via ssh without entering the password, everything worked fine till I made the user's folder hidden (Added . to name /home/.user). ...
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How to allow SSH-key-based login (only) via pam rules

I am trying to allow an application to log in using only an SSH key (no password required). The application is a backup/restore system called Veeam. It uses vmtoolsd to log in in stead of SSH / SCP. ...
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Permanently add key to ssh-agent and delete key from disk exactly like in Windows

In Windows, you can run ssh-agent as a service, permanently add ssh keys (per user), and then delete those key files from disk so they are no longer there at all. You cannot retrieve the key from the ...
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SSH to user other than root

I can use ssh -i ~/.ssh/id_rsa root@SERVER to connect to my Ubuntu VM but I have another user in same VM and I would like to connect directly to it. I tried ssh -i ~/.ssh/id_rsa newuser@SERVER but I ...
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difference between authorized_keys and known_hosts files? [duplicate]

When it comes to the use of ssh service (client & server), I'm quite confused as to the use of these two files, : authorized_keys known_hosts what's the difference between them? what are their ...
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Suddenly unable to ssh into CentOS 8 server with error "Server refused our key"

I have a CentOS 8 server set up with a few users with SSH keys, and I haven't had any problems logging in with any of the users as of a few days ago. (Password authentication is disabled, so is root ...
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How does sshd know which user belongs to which AuthorizedKeysFile?

If I set a custom path for AuthorizedKeysFile, how does sshd decide which user this key belongs to? AuthorizedKeysFile Specifies the file that contains the public keys that can be used for user ...
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2 votes
1 answer
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SFTP Public Key Authentication works for one user and no others

I have one user who is able to able to login via SFTP using a public key, but can not setup any others to work the same way. I've searched for other similar questions and the solution has usually been ...
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236 views

SSH public key not sending to server

I'm having difficult with the following, I'm trying to configure a cron job for rsync to sync between two serves, for which I need server A (local) to ssh into server B using a public key. I ...
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1 answer
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sudo ssh: load pubkey Permission denied

user1 needs to be able to su to user2 on host1, and then ssh to host2 using public key authentication. The key is in /home/user2/.ssh/id_rsa on host1. It works with sudo -s... [user1@host1] $ sudo -u ...
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How does one use SFTP noninteractively to download a file from a remote host?

I have a laptop and a raspberry pi acting as a storage server. I'd like to know how to download a file without any user interaction other than running the program. I read through the man page, and ...
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3 votes
1 answer
545 views

SSH-RSA public key authentication explanation needed

I have recently upgraded my workstation - Fedora 31 to Fedora 34. As it usually happens after upgrade some of ssh alogrithms become obsoleted and I have to add extra lines to .ssh/config and I am okay ...
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Different ssh rc commands for different logins

So, I have a silly question. I have a linux server, and I regularly ssh into it with various devices. I have an 'rc' file in my .ssh directory to print some ASCII art text on login just for decoration....
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Can ssh-copy-id be configured to save to a different authorized_keys file?

Looking at the source of ssh-copy-id at openssh-portable/ssh-copy-id at master · openssh/openssh-portable · GitHub it looks like ssh-copy-id can copy the key to user specified authorized_keys files on ...
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Copying key to /root/.ssh/authorized_keys

I'm trying to copy a file (contains keys) to remote machine using below script. But the below error /root/.ssh/authorized_keys: Permission denied #!/bin/bash for i in `cat hosts` do cat team.keys | ...
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Linux is slow in authenticating password

I started using PuTTY public and private key pairs recently to login my local virtual machine using ssh. Initially, it worked quite fast. From asking username to starting a shell/command, it took less ...
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ssh error because pub key not present

I have a .ssh directory with a lot of keys to a lot of systems, using a collection of ssh config files, this has worked flawlessly for a few years now. I reinstalled my machine yesterday (from Ubuntu ...
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1 answer
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When using SSH is it possible to prevent password authentication only if a certificate exists in the user's home directory?

I am spinning up a public facing server with SSH running for remote access. Every standard human user will be using a certificate for authentication. However one very limited functional account exists ...
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2 answers
376 views

Searching keys with gpg results in key server failure

The following simple command is failing $ gpg --search-keys "hi" gpg: error searching keyserver: Server indicated a failure gpg: keyserver search failed: Server indicated a failure ...
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1 vote
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Ubuntu 16.04.7 sshd won't accept 4096 bit public key authentication

[Ubuntu 16.04.7, OpenSSH_7.2p2 Ubuntu-4ubuntu2.10, OpenSSL 1.0.2g 1 Mar 2016, updated today as part of this activity] I'm trying to setup public key authentication for a new user I want to give ...
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1 answer
807 views

SSH Publickey+TOTP and Password+TOTP simultaneously

I am trying to setup an SSH server where some users prefer to use an SSH key but others prefer LDAP provided passwords. I found out that I can set in sshd_config for publickey + PAM or PAM only ...
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2 answers
605 views

I removed my public key from my ~/.ssh directory, why can I still access host without password?

I generated a public/private key pair on my client machine. They are in ~/.ssh as id_rsa and id_rsa.pub. I added the public key to the host machine's authorized_keys file, and now I can successfully ...
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6 votes
2 answers
2k views

how to append public keys to remote host instead of copy it

I used in my bash script the follwing cli , in order to send the public key to remote machine sshpass -p $pass scp /root/.ssh/authorized_keys root@$remote_host:~/.ssh/authorized_keys but since we ...
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0 votes
1 answer
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No support authentication methods available (server sent: publickey)

I am trying to connect to my ubuntu instance after rebooting it up off of AWS. The public IPv4 address changed, and I updated the Host Name on PuTTY expecting it to connect like it always does after ...
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2 votes
1 answer
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SSH client seems to be checking '/dev/null' instead of 'known_hosts' file when checking remote server's ECDSA key

I'd like to know why my known_hosts file doesn't seem to be checked correctly while using SSH. In short, my guess is that my SSH client is checking /dev/null instead of the known_hosts file. Details ...
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4 votes
1 answer
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encrypt private keys for dropbear ssh-access

I'd like to use dropbear as an alternative, minimal ssh-server and -client. dropbear allows the use of private-public-keys for ssh-access, although the keys are not identical to the ones used by ...
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How to delete SSH keys

I am new to this field. I had a server administrator but he left. I assume his key was installed in authorized_keys. How to delete these keys if they exist. How can I find out if they are really (...
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DEBIAN SSH Server with google authenticator. How to allow “publickey+2FA” for user1 and “password+2FA” for user2?

0 The problem is very simple but I'm struggling for hours without finding the good solution. I want "user1" to log in to the SSH server with publickey + 2FA code (but no password prompt, ...
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0 votes
1 answer
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Trouble verifying linux, even after downloading key I get "No public key"

Following these instructions, I downloaded and unpacked the kernel. https://priyachalakkal.wordpress.com/2013/01/19/verifying-digital-signature-using-gpg/ Then I tried to verify the signature but I ...
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Trouble accessing remote server with public key

i am posting this question after extensive search in google to create public key and accessing server using public key, i am still unable to resolve this issue, as i am getting below error. OpenSSH_7....
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1 answer
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ssh login public key authentication private or public key

What should be the value of the -i option when login in using ssh? I had previously supplied the public key ssh -i ~/.ssh/id_rsa.pub on an OpenBSD machine that worked but when trying to ssh into an ...
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0 answers
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SSH - Key signing of ED25519 style keys does not work

Trying to set up a SSH Cert Authority so I can centralize new key setup rather than modifying the authorized keys on each of my machines. I found something really odd - the keys that I develop work ...
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0 votes
1 answer
90 views

SSH PKI authentication

At my company, we are currently integrating AD authentication to our Linux servers. I've been able to complete this part using PBISO (Power Broker Identity Service). Users are able to login using AD ...
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1 vote
2 answers
921 views

Can a user with no password set login with ssh?

First, I want to be clear, I am not asking about just using public key authentication without a prompt. I have a use case where a user must only be allowed access through SSH public key authentication....
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4 votes
0 answers
512 views

gnome-keyring: couldn't find any place to import files

I need to use a client certificate. I was able to import it successfully on Windows and Mac, however when I am trying to import it on Linux I am getting the following error: $ gnome-keyring import ...
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ssh server is rejecting public key [duplicate]

Sometimes I need to login on my Linux Mint 19 PC remotely via ssh. To make this more secure I try to switch to use Public Key authentication (as I already use it on my raspberries). Basically the ...
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