How to Use YubiKey/FIDO2 Device with ED25519-SK Keys for SSH Agent on MacOS 15.3+

To create a detailed article on using SSH keys with MacOS 15.3, we'll cover key concepts, provide subtitles, use proper formatting, and include code blocks for programming examples.

Using SSH Keys with MacOS 15.3

Introduction

With the latest MacOS 15.3, managing SSH keys has become more streamlined. This article will guide you through the process of generating, configuring, and using SSH keys for secure remote access.

Generating SSH Keys

1. Open Terminal: Locate the Terminal application in your Applications > Utilities folder or use Spotlight search.

2. Generate a new SSH key pair:

ssh-keygen -t rsa -b 4096 -C "[email protected]"

Replace [email protected] with your email address. The -t option specifies the type of key to generate, -b sets the key length, and -C adds a comment field for your email address.

3. When prompted, press Enter to accept the default file location and name for your new public and private key files. Alternatively, specify a custom location and name if desired.

Configuring SSH Agent

1. Start the SSH agent:

eval "$(ssh-agent -s)"

2. Add your newly generated SSH key to the SSH agent:

ssh-add ~/.ssh/id_rsa

Replace id_rsa with the name of your private key file.

Configuring SSH Config File

1. Open or create the SSH config file:

nano ~/.ssh/config

2. Add the following lines to the file, replacing your_server with the hostname or IP address of the remote server and ~/.ssh/id_rsa.pub with the path to your public key file:

Host your_server
  HostName your_server
  User your_username
  IdentityFile ~/.ssh/id_rsa
  Port your_port

Replace your_username with your remote server username and your_port with the SSH port number if necessary.

Testing SSH Key Authentication

Attempt to connect to your remote server using the SSH key:

ssh your_server

If the connection is successful, you'll be logged into your remote server without needing to enter a password.

Summary

• Generated a new SSH key pair using ssh-keygen
• Configured the SSH agent with ssh-agent and ssh-add
• Created an SSH config file to manage multiple servers
• Tested SSH key authentication with ssh

References

• SSH Key Management
• SSH Key Authentication
• MacOS SSH Configuration
• SSH Key Management on MacOS