Archived Documentation

This documentation is no longer maintained and may contain outdated information. It is preserved for historical reference.

SSH Key Management

This page is meant to assist in setting up and maintaining SSH keys.

SSH Directory Permissions

chmod 700 ~/.ssh
chmod 644 ~/.ssh/authorized_keys
chmod 644 ~/.ssh/known_hosts
chmod 644 ~/.ssh/config
chmod 600 ~/.ssh/id_ed25519
chmod 644 ~/.ssh/id_ed25519.pub
chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub

Generating SSH Keys

ED25519

Change to ~/.ssh:
```
cd ~/.ssh
```
Generate an Ed25519 ssh key:
```
ssh-keygen -t ed25519 -a 256
```

Generate an Ed25519 ssh key with a specific name:

ssh-keygen -f <keyname> -t ed25519 -a 256

RSA

Change to ~/.ssh:
```
cd ~/.ssh
```
Generate a RSA ssh key:
```
ssh-keygen -t rsa -b 4096 -o -a 256
```

Generate a RSA ssh key with a specific name:

ssh-keygen -f <keyname> -t rsa -b 4096 -o -a 256

Verifying SSH Keys

Verify SSH Key Password

Change to ~/.ssh:
```
cd ~/.ssh
```
Verify password:
```
ssh-keygen -y -f id_ed25519
```

Upon entering successful passphrase, it prints the pubkey:

Enter passphrase: 
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJAZcdEIpPbJal7CEsIpaHzBEjs/8nedIvDA/sDlvqll chuck@gaming

Enter the wrong passphrase:

ssh-keygen -y -f id_ed25519
Enter passphrase: 
Load key "id_ed25519": incorrect passphrase supplied to decrypt private key

Verify SSH Private Key Matches Public Key

Change to ~/.ssh:
```
cd ~/.ssh
```

Verify ssh key matches it’s private key:

ssh-keygen -l -f id_ed25519; ssh-keygen -l -f id_ed25519.pub

Output should match:

256 SHA256:W5o5+DV3Jaba4txzQ58gZuIZvZD44McIU7tV9I4LZpw chuck@gaming (ED25519)
256 SHA256:W5o5+DV3Jaba4txzQ58gZuIZvZD44McIU7tV9I4LZpw chuck@gaming (ED25519)

Modifying SSH Keys

Change SSH Key Password

Change to ~/.ssh:
```
cd ~/.ssh
```
Change password:
```
ssh-keygen -p -f id_ed25519
```

Change SSH Key Comment

Change to ~/.ssh:
```
cd ~/.ssh
```

Change comment (email):

ssh-keygen -c -f id_ed25519
Enter passphrase: 
Key now has comment 'chuck@hostname'
Enter new comment: user@newname
The comment in your key file has been changed.

SSH-Agent

Add the key to the ssh-agent.
```
ssh-add keyname
```
Add the key to the server using the credentials from the config file.
```
ssh-copy-id -i keyname servername
```