Ftp Sftp Filezilla

How to Extract SFTP SSH Key from Key Cache in FileZilla FTP Client

If you’ve ever connected to a server via SFTP using FileZilla, you may have accepted an SSH key that was added to FileZilla’s key cache. However, what do you do if you want to use that cached key with other SFTP applications? This is a common scenario for many users, and today we will guide you through the process of extracting this SSH key for broader use in other programs.

Understanding the SSH Key Storage

When you connect to a server using SFTP (Secure File Transfer Protocol), your client manages the security of this connection through SSH (Secure Shell) keys. FileZilla, like many other SSH clients, caches these keys to streamline future connections. Here’s how they store the keys:

  • OpenSSH Client: When using a standard OpenSSH client (such as through Cygwin or Linux), the SSH keys are generally stored in the ~/.ssh/known_hosts file.
  • PuTTY: On Windows, if you use PuTTY, the keys can be found in the Windows Registry at HKCUR\Software\SimonTatham\PuTTY\SshHostKeys. It’s notable that these keys might be encoded in hexadecimal format.

Steps to Extract Your SSH Key

To extract the SSH key from FileZilla’s cache, follow these steps based on the client you are using:

Step 1: Locate the Key

For OpenSSH Users:

  1. Open your Terminal: You can use any terminal interface like Terminal for macOS, Cygwin, or Linux terminal.
  2. Navigate to the SSH directory: Use the command: 
    cd ~/.ssh
    This will take you to the directory where the known hosts are stored.
  3. Open the known_hosts file: You can view the file using a command like: 
    cat known_hosts
  4. Identify the Host Key: Look through the lines for the specific server’s line that corresponds with the SSH key you accepted.

For PuTTY Users:

  1. Access the Windows Registry: You can do this by typing regedit in the Run dialog (Win + R).
  2. Navigate to PuTTY keys: Go to: 
    HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\SshHostKeys
  3. Find Your Key: The keys will be listed here, but note that they may appear in hexadecimal format, which you will need to convert for use in other applications.

Step 2: Save Your Key to a File

Once you’ve located the required host key, you may want to save it into a separate key file. Here’s how:

  • Simply copy the corresponding line from known_hosts (for OpenSSH) and paste it into a new file.
  • Make sure to save it with an appropriate file extension, such as .ssh or .key.

Step 3: Use Your Key in Other Applications

Now that you have extracted the SSH key, you can integrate it into other SFTP applications that require a keyfile. Typically, you would follow their specific instructions to upload or submit the key.

Conclusion

Extracting an SFTP SSH key from FileZilla’s cache enables you to use the same secure connections across multiple applications. Whether you’re on Linux or Windows, understanding where to find your keys and how to extract them can save you time and hassle in managing secure file transfers. Remember to handle your SSH keys with care, as they play a critical role in maintaining your connection security.

By following the steps outlined above, you should now be equipped to extract and utilize your SFTP SSH key with ease.