Documentation/content/security/ssh-key.md

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key title parent order SSHKey Adding an SSH key to your account Security 20

It is recommended to use one key per client. It means if you access your Codeberg repository from your home PC, your laptop and your office PC you should generate separate keys for each machine.

Generating an SSH key (pair)

1. Open Terminal on Linux/macOS, or Git Bash on Windows.

2. Paste the text below

   $ ssh-keygen -t ed25519 -a 100
   

   This will generate a new SSH key.

   > Generating public/private ed25519 key pair.
   

3. When you're prompted to "Enter a file in which to save the key," press Enter. This accepts the default file location:

   > Enter file in which to save the key (/home/knut/.ssh/id_ed25519): [Press enter]
   

4. You will be asked for a passphrase, enter one if you'd like to or leave the prompt empty.

The private key part of your SSH key can be protected by a passphrase. This adds a layer of authentication which increases security. Be aware that this will only be helpful for certain attack scenarios and does not offer 100% protection. It is recommended to keep your private key safe and - well - private.

Add the SSH key to Codeberg

1. Copy the SSH key to your clipboard. Attention: Copy only the public part of the key not the private one. You can identify it by the .pub extension. By default, you can find the public key in $HOME/.ssh/id_ed25519.pub.

   On Linux you can use xclip on the command line. You may need to install it from your package manager.

   $ xclip -selection clipboard < ~/.ssh/id_ed25519.pub
   # Copies the contents of the id_ed25519.pub file to your clipboard
   

   On Windows you can use clip on the command line

   $ clip < ~/.ssh/id_ed25519.pub
   # Copies the contents of the id_ed25519.pub file to your clipboard
   

   On macOS you can use pbcopy on the command line

   $ pbcopy < ~/.ssh/id_ed25519.pub
   # Copies the contents of the id_ed25519.pub file to your clipboard
   

   Alternatively you can locate the hidden .ssh folder, open the file in your favorite text editor, and copy it to your clipboard.

2. Navigate to your user settings

3. Go to the settings section SSH / GPG Keys and click on Add key.

4. Give an appropriate name for the key.
5. Paste your key string into content field.
6. Click the add key button.

You can always access your SSH public keys from https://codeberg.org/username.keys, substituting in your Codeberg username.

Test the SSH connection

Do this simple test:

$ ssh -T git@codeberg.org

The output should look like this:

Hi there! You've successfully authenticated, but Gitea does not provide shell access.
If this is unexpected, please log in with password and setup Gitea under another user.

Note: All Codeberg users share a single Unix user named git which is used to check out repositories. Depending on the key provided, permission is granted or denied. You can check out all repositories with your key which you have permission for. You can push code to all repositories where you have write access.

Verifying your SSH Key

Anyone can add a random SSH key; fortunately, Codeberg provides a mechanism to verify that the key belongs to you. Every keypair consists of a public and a private key that are connected to one another. Using this private key, you can sign the provided message. If the signed message is valid, Codeberg can confirm that the added key is yours.

1. Go to the SSH/GPG Keys tab in your Codeberg settings.
2. Click on the Verify button by the SSH key you would like to verify.
3. Codeberg will show a token, under the textbox you can copy the command, replace /path_to_your_pubkey accordingly to the correct path.
4. Copy the output including the -----BEGIN SSH SIGNATURE----- and -----END SSH SIGNATURE-----.
5. Paste it into the large textbox and click the Verify button.

Avoid re-typing the passphrase

Assuming you've created a secure key with passphrase, SSH will prompt you for your passphrase for every connection. Common desktop environments like macOS or GNOME will offer you to cache your passphrase via an SSH agent.

If you are working at the command line, you can alternatively do this directly:

$ eval $(ssh-agent)
$ ssh-add
## enter your passphrase once, this is then cached.

Attribution
This guide is derived from GitHub Docs, used under CC-BY 4.0.