SSH Keys

When using a secure connection, Screens can authenticate with the remote machine using either a username and password or a private SSH key.

How to Authenticate with a Private SSH Key

Screens for macOS

• In the saved screen's settings, click the Secure Connection tab.
• Click the key icon to browse for a private SSH key.

The key icon will turn blue upon loading a valid private key.

Screens for iOS

In order for Screens for iOS to use a SSH key, it needs to be imported. Our recommendation is to copy the private key content in the clipboard (via Notes, Mail, etc.)

Method 1: Clipboard. You can copy the key content and send it to yourself via Mail:

Then, simply copy the key content on your iOS device and Screens will be able to import it from the Clipboard.

Method 2: Finder. Use Finder under macOS 10.14 Yosemite or later to import the key. Simply drag your private key under the Screens icon:

To add a SSH key:

• Open the Screens app settings
• Tap on SSH Keys
• Tap the + button
• Select the source. Clipboard for Method 1 or iTunes (Finder) for Method 2.
• Give your key a name

To use a SSH key:

• Edit a saved screen.
• Under Secure Connection, tap Advanced.
• Next to the Password field, tap the key icon.

• Choose Keys or 1Password to browse for a private key.

Considerations

• Due to technical considerations, Screens doesn't support the newer OpenSSH key format. We recommend using the PEM format..
• Screens supports RSA keys of 2048-bits or less; 4096-bits or greater are unsupported.

Security

SSH keys are securely stored in the iOS/macOS Keychain.

Creating a Key Pair

You can use your Mac's ssh-keygen command-line tool in Terminal to create a private and a public key.

• Open Terminal.

• Type one of the following command at the prompt, depending if you want a passphrase or not:

  • ssh-keygen -N "" -m PEM -f MyKey && open .

  • ssh-keygen -N "mypassphrase" -m PEM -f MyKey && open .

• You can replace MyKey with any name you like. This is used to identify the key in Screens.

• Finder will open a new window. You will find the two files (MyKey is the private key and MyKey.pub public key) inside the folder.

• Copy the public key to the remote computer.

• Append the public key to the list of authorized keys. You can do this with the following command in Terminal:

  • cat MyKey.pub >> /Users/my_username*/.ssh/authorized_keys

    * Replace my_username with your Mac username. If you don't know your username, here's how to find out.

• You can now use the private key to authenticate.

• If you already have a private key without a public key, you can create the public key with the following command in Terminal:

  • ssh-keygen -y -f MyKey > MyKey.pub