# Lab 2: Passwordless SSH Access from PC and Mobile to Raspberry Pi

Objective
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• Enable SSH key‑based authentication from both PC and mobile
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• Store multiple public keys inside the file
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• Apply correct permissions to the directory
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• Verify passwordless login from both devices

Environment
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• Raspberry Pi OS (user: your-username)
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• Windows PC with an SSH key pair
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• Mobile device using Termius
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• Raspberry Pi reachable via SSH at your-raspberry-ip

**1. Generate an SSH key on the PC**

Create a new SSH key pair on Windows:

`ssh-keygen -t ed25519 -C "your-device-name"`

The public key is located in:

`%USERPROFILE%\.ssh\id_ed25519.pub`

**2. Retrieve the SSH key from the mobile device (Termius)**

Termius automatically generates an SSH key pair.

To view the public key:

* Open Termius
* Go to **Settings → Keys**
* Select your key
* Copy the public key

**3. Add both public keys to the Raspberry Pi**

Connect to the Raspberry Pi (password allowed temporarily) and open:

`nano ~/.ssh/authorized_keys`

Paste:

* the PC public key
* the mobile public key

Save and exit.

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**4. Set correct permissions**

Ensure the `.ssh` directory and the `authorized_keys` file have the proper permissions:

* `.ssh` directory → `700`
* `authorized_keys` file → `600`
* Owner → `your-username`

**5. Test passwordless access**

**From the PC**

Run:

`ssh your-username@your-raspberry-ip`

The login should complete without asking for a password.

**From the mobile device (Termius)**

Open the saved connection and verify that it logs in automatically.