How do I generate SSH keys on Mac OS?

SSH keys provide a secure way to authenticate when connecting to a server via SSH. A key pair consists of a private key, which remains on your device, and a public key, which is added to the server.

Step 1: Open Terminal

Open the Terminal application on your Mac.

You can find it in:

Applications → Utilities → Terminal

Step 2: Generate the SSH Key Pair

Run the following command:

ssh-keygen

You will be prompted to choose a location for the key files:

Enter file in which to save the key (/Users/username/.ssh/id_rsa):

Press Enter to use the default location, or specify a custom path.

Step 3: Set a Passphrase

Next, you will be asked to enter a passphrase:

Enter passphrase (empty for no passphrase):

A passphrase is optional, but it adds an extra layer of protection to your private key. For better security, use a strong and memorable passphrase.

You will then be asked to enter the passphrase again for confirmation.

Step 4: Verify the Generated Keys

After the process is complete, you will see a message similar to:

Your identification has been saved in /Users/username/.ssh/id_rsa.
Your public key has been saved in /Users/username/.ssh/id_rsa.pub.

The key pair will be stored in the ~/.ssh directory.

Generated Files

Two files will be created:

File	Description
id_rsa	Private key
id_rsa.pub	Public key

Private Key

~/.ssh/id_rsa

The private key should remain on your computer and should never be shared.

Public Key

~/.ssh/id_rsa.pub

The public key is the file that should be added to the server.

Display the Public Key

To view the contents of the public key, run:

cat ~/.ssh/id_rsa.pub

Copy the entire output.

Add the Public Key to the Server

Paste the public key into the following file on the server:

~/.ssh/authorized_keys

If the file does not exist, create it and add the key on a new line.

Test the Connection

After adding the public key to the server, connect using SSH:

ssh username@server-address

If the configuration is correct, the server will authenticate you using your SSH key.

Security Recommendations

• Never share your private key.
• Store your private key only on trusted devices.
• Protect the key with a strong passphrase whenever possible.
• Remove unused public keys from the server regularly.

Summary

Generating SSH keys on macOS requires running the ssh-keygen command in Terminal. This creates a private key (id_rsa) and a public key (id_rsa.pub) in the ~/.ssh directory. The public key should be added to the server’s authorized_keys file, while the private key should be kept secure and never shared.