| VPN | License Key System | Legit Key Format | |-----|-------------------|------------------| | | Account-based, but can activate via key from retailers | Alphanumeric code | | Surfshark | No traditional key; uses activation code from resellers | 24-character code | | ProtonVPN | Uses voucher codes (entered in app) | XXXX-XXXX-XXXX | | Windscribe | Uses "Soda" codes or license keys for Pro version | Custom alphanumeric |