In iTerminal 4.0, we have added support of importing from and exporting to the iCloud Drive. It's more easy and convenient to manage private keys on iTerminal.
You can import a key to iTerminal in three ways:
Option 1 : the most easy and secure way is to use your iCloud Drive. First copy or upload a key file to your iCloud Drive under "/iterminal/keys" folder. Then start iTerminal and go to Settings->Key Management. Tap "Add" then tap "Import from iCloud". You will see a list of key files under "/iterminal/keys" folder. Pick the one you want to import. The key content will be imported. Tap "Save" to save the key to iTerminal.
Option 2: copy and paste the content from a key file directly in Settings -> Key Management->Add. You will have to first make the key content text available on your device.
Option 3: import a key file using "Open In". You can email a key file to yourself and open it with iTerminal. Due to iOS restriction, you will need to rename your key file before attaching it in your email. For an OpenSSH private key like *.pem file, rename it to *.pri_key. For a Putty private key like *.ppk file, you can import it directly and it will be converted to a PEM key. Your iOS device will automatically show iTerminal in the list of Apps that can open these files when you long press the attached key file in your Email.
You can also transfer existing key files among different iTerminal versions and devices. First open an existing key file from Settings->Key Management. Tap "Export to iCloud" button. Then open a different iTerminal App and import the key as described in Option 1.