It is possible to configure your Pi to allow your computer to access it without providing a password each time you try to connect. To do this you need to generate an SSH key:
Passwordless SSH access. It is possible to configure your Pi to allow your computer to access it without providing a password each time you try to connect. To do this you need to generate an SSH key: Check for existing SSH keys. First, check whether there are already keys on the computer you are using to connect to the Raspberry Pi: ls /.ssh. How to generate an SSH key and add your public key to the server for authentication Step 1: Check for SSH Keys. First, check for existing SSH keys on your computer. Step 2: Generate a new SSH key. With your command line tool still open, enter the text shown below. Step 3: Add your key to the. If you don't want to reenter your passphrase every time you use your SSH key, you can add your key to the SSH agent, which manages your SSH keys and remembers your passphrase. Generating a new SSH key. Open Terminal Terminal Git Bash. Paste the text below, substituting in your GitHub email address. $ ssh-keygen -t rsa -b 4096 -C 'youremail.
Check for existing SSH keys
First, check whether there are already keys on the computer you are using to connect to the Raspberry Pi:
If you see files named
id_rsa.pub or id_dsa.pub you have keys set up already, so you can skip the generating keys step (or delete these files with rm id* and make new keys).
Generate new SSH keys
To generate new SSH keys enter the following command:
Upon entering this command, you'll be asked where to save the key. We suggest you save it in the default location (
/home/pi/.ssh/id_rsa ) by just hitting Enter .
You'll also be asked to enter a passphrase. This is extra security which will make the key unusable without your passphrase, so if someone else copied your key, they could not impersonate you to gain access. If you choose to use a passphrase, type it here and press
Enter , then type it again when prompted. Leave the field empty for no passphrase.
Now look inside your
.ssh directory:
and you should see the files
id_rsa and id_rsa.pub :
The
id_rsa file is your private key. Keep this on your computer.
The
id_rsa.pub file is your public key. This is what you share with machines you want to connect to. When the machine you try to connect to matches up your public and private key, it will allow you to connect.
Take a look at your public key to see what it looks like:
It should be in the form:
Copy your public key to your Raspberry Pi
To copy your public key to your Raspberry Pi, use the following command, on the computer you will be connecting from, to append the public key to your
authorized_keys file on the Pi, sending it over SSH:
Note that this time you will have to authenticate with your password.
Generate Authorized Key With Ssh-keygen Key
Alternatively, if the
ssh-copy-id is not available on your system, you can copy the file manually over SSH:
If you see the message
ssh: connect to host <IP-ADDRESS> port 22: Connection refused and you know the IP-ADDRESS is correct, then you probably haven't enabled SSH on your Pi. Run sudo raspi-config in the Pi's terminal window, enable SSH, and then try to copy the files again.
Now try
ssh <USER>@<IP-ADDRESS> and you should connect without a password prompt.
If you see a message 'Agent admitted failure to sign using the key' then add your RSA or DSA identities to the authentication agent
ssh-agent then execute the following command:
If this did not work, delete your keys with
rm ~/.ssh/id* and follow the instructions again.
You can also send files over SSH using the
scp command (secure copy). See the SCP guide for more information.
Let macOS store your passphrase so you don't have to enter it each time
If you're using macOS and after verifying that your new key allows you to connect, you can optionally choose to store the passphrase for your key in the macOS Keychain. This will make it so that you don't have to enter the passphrase each time you connect to your Pi.
Run the following command to store it in your keychain:
Overview
Public key authentication is a way of logging into an SSH/SFTP account using a cryptographic key rather than a password.
If you use very strong SSH/SFTP passwords, your accounts are already safe from brute force attacks. However, using public key authentication provides many benefits when working with multiple developers. For example, with SSH keys you can
How To Create Ssh Keygen
How Public Key Authentication Works
Keys come in pairs of a public key and a private key. Each key pair is unique, and the two keys work together.
These two keys have a very special and beautiful mathematical property: if you have the private key, you can prove you have it without showing what it is. It's like proving you know a password without having to show someone the password.
Public key authentication works like this:
You don't have to do the math or implement the key exchange yourself. The SSH server and client programs take care of this for you.
Generate an SSH Key Pair
You should generate your key pair on your laptop, not on your server. All Mac and Linux systems include a command called ssh-keygen that will generate a new key pair.
If you're using Windows, you can generate the keys on your server. Just remember to copy your keys to your laptop and delete your private key from the server after you've generated it.
To generate an SSH key pair, run the command ssh-keygen.
Ssh Add Authorized Keys
It will look like this when you run it:
You'll be prompted to choose the location to store the keys. The default location is good unless you already have a key. Press Enter to choose the default location.
Next, you'll be asked to choose a password. Using a password means a password will be required to use the private key. It's a good idea to use a password on your private key.
After you choose a password, your public and private keys will be generated. There will be two different files. The one named id_rsa is your private key. The one named id_rsa.pub is your public key.
You'll also be shown a fingerprint and 'visual fingerprint' of your key. You do not need to save these.
Configure an SSH/SFTP User for Your Key![]() Method 1: Using ssh-copy-id
Now that you have an SSH key pair, you're ready to configure your app's system user so you can SSH or SFTP in using your private key.
To copy your public key to your server, run the following command. Be sure to replace 'x.x.x.x' with your server's IP address and SYSUSER with the name of the the system user your app belongs to.
Method 2: Manual Configuration
If you don't have the ssh-copy-id command (for example, if you are using Windows), you can instead SSH in to your server and manually create the .ssh/authorized_keys file so it contains your public key.
First, run the following commands to make create the file with the correct permissions.
Next, edit the file .ssh/authorized_keys using your preferred editor. Copy and paste your id_rsa.pub file into the file.
Log In Using Your Private Key
You can now SSH or SFTP into your server using your private key. From the command line, you can use:
If you didn't create your key in the default location, you'll need to specify the location:
If you're using a Windows SSH client, such as PuTTy, look in the configuration settings to specify the path to your private key.
Granting Access to Multiple Keys
The .ssh/authorized_keys file you created above uses a very simple format: it can contain many keys as long as you put one key on each line in the file.
If you have multiple keys (for example, one on each of your laptops) or multiple developers you need to grant access to, just follow the same instructions above using ssh-copy-id or manually editing the file to paste in additional keys, one on each line.
When you're done, the .ssh/authorized_keys file will look something like this (don't copy this, use your own public keys):
Additional InformationRetrieve Your Public Key from Your Private Key
The following command will retrieve the public key from a private key:
This can be useful, for example, if your server provider generated your SSH key for you and you were only able to download the private key portion of the key pair.
Note that you cannot retrieve the private key if you only have the public key.
Correcting Permissions on the .ssh Directory
The instructions in this article will create your server's .ssh directory and .ssh/authorized_keys file with the correct permissions. However, if you've created them yourself and need to fix permissions, you can run the following commands on your server while SSH'd in as your app's system user.
![]() Disabling Password Authentication
NOTE: When changing anything about the way SSH is accessed(ports, authentication methods, et cetera), it is very strongly recommended to leave an active root SSH session open until everything is working as intended. This ensures you have a way to revert changes in the event something goes wrongand logins are not working properly.
As an extra security precaution, once you have set up SSH keys, you may wish to disable password authentication entirely. This will mean no users will be able to log into SSH or SFTP without SSH keys. Anyone entering a password will receive a message like:
Ssh Authorized Keys File Location
Or:
Disabling password authentication is an excellent way to improve server security. Please see our guide here for the steps to accomplish this goal.
Then, test whether you're able to log in with a password by opening a new SSH or SFTP session to the server. Passwords should not be able to be used and, if everything has been done correctly, an error will be issued when someone tries to use a password. Unless this setting is changed back to allow password authentication, no users will be able to log in without an SSH key set up.
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