# SSH
## Key Generation
```bash
ssh-keygen -t ed25519 -C "
[email protected]" # recommended (Ed25519)
ssh-keygen -t rsa -b 4096 # RSA fallback
```
## Copy Public Key to Server
```bash
ssh-copy-id user@host
```
## Fix "Permissions are too open"
Private key files must be readable only by the owner:
```bash
chmod 600 ~/.ssh/id_ed25519 # or id_rsa for RSA keys
chmod 644 ~/.ssh/id_ed25519.pub
chmod 700 ~/.ssh
```