Sign in with an SSH key

An SSH key is a pair of files: a private key that stays on your computer, and a public key that you give to FiniteHost. When you connect, your SFTP app proves it holds the private key, so you never type a password. Keys are also much harder to guess or steal than a password.

You can use a key and a password side by side. Adding a key does not switch the password off.

Before you start#

• You have connected at least once with a password, or you know your connection details from Connect with SFTP.
• Your plan is Active (or in its grace period). Keys only work while SFTP is enabled for the plan.
• You can add up to 10 keys, for example one per computer or per team member.

Create a key on Windows 10 or 11#

Windows includes OpenSSH, so no extra software is needed.

1. Open PowerShell from the Start menu.
2. Run the key generator with the command below. Replace the comment with something that names this computer.

ssh-keygen -t ed25519 -C "asha@laptop"

3. Press Enter to accept the default file, C:\Users\<you>\.ssh\id_ed25519.
4. Type a passphrase and press Enter, then type it again. A passphrase protects the key if your laptop is lost; you can leave it empty, but we recommend one.
5. Show the public key and copy the whole single line it prints:

Get-Content $env:USERPROFILE\.ssh\id_ed25519.pub

The line looks like ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAA… asha@laptop.

Create a key on macOS or Linux#

1. Open Terminal.
2. Run the key generator:

ssh-keygen -t ed25519 -C "asha@laptop"

3. Press Enter to accept the default file, ~/.ssh/id_ed25519, then set a passphrase.
4. Show the public key and copy the whole line:

cat ~/.ssh/id_ed25519.pub

On macOS you can copy it straight to the clipboard with pbcopy < ~/.ssh/id_ed25519.pub.

Using PuTTYgen instead#

WinSCP and FileZilla on Windows can also use keys made with PuTTYgen, which comes with PuTTY and WinSCP.

1. Open PuTTYgen, choose EdDSA (Ed25519) as the key type and click Generate, moving the mouse until it finishes.
2. Enter a passphrase, then click Save private key to save a .ppk file.
3. Copy the public key from the box at the top labelled Public key for pasting into OpenSSH authorized_keys file.

Add the public key in the panel#

1. Open Files (SFTP) in the panel.
2. Scroll to the SSH keys card and find Add a public key.
3. Paste the one-line public key into the box.
4. Click Add key. The key appears in the list with the end of its fingerprint and the comment you gave it.
5. Wait about a minute for the storage server to pick it up.

The panel accepts these key types: ssh-ed25519 (recommended), ssh-rsa, and ecdsa-sha2-nistp256, ecdsa-sha2-nistp384 or ecdsa-sha2-nistp521.

Use the key in your SFTP app#

FileZilla#

1. Open File → Site Manager and select your FiniteHost site.
2. Set Logon Type to Key file.
3. Browse to your private key: id_ed25519 (in your .ssh folder) or your .ppk file. FileZilla may offer to convert an OpenSSH key; accept.
4. Click Connect.

Alternatively, add the key once for all sites under Edit → Settings → SFTP → Add key file.

WinSCP#

1. Select your site in the Login window and click Edit.
2. Click Advanced, then go to SSH → Authentication.
3. Choose the Private key file, your .ppk file. WinSCP offers to convert an OpenSSH key to .ppk; accept.
4. Click OK, Save, then Login.

Command line#

sftp -P 2222 -i ~/.ssh/id_ed25519 t3d2ca2b860@sftp.finitehost.com

On Windows PowerShell use -i $env:USERPROFILE\.ssh\id_ed25519. If the key is in the default place, you can leave out -i completely.

Troubleshooting#

• "Paste a public key that starts with ssh-ed25519, ssh-rsa or ecdsa-sha2": you pasted the private key, the multi-line PuTTYgen format, or a line with a break in it. Copy the .pub file's single line again.
• "Up to 10 keys": the account already has 10 keys. Ask support to remove ones you no longer use.
• The app still asks for a password: the app is not offering the key. Check the key file path, and that you chose the private key, not the .pub file.
• Server refused our key: wait a minute after adding it, and check that the plan is Active.

What's next#

• Folder layout: where your site and app files live.
• Upload your website.
• Account security: how sign-in and passwords work across FiniteHost.