We have two different softwares Zetsal App and OpenVPN. these are the most advanced and secured VPN Softwares.
1. OpenVPN runs through TLS protocol which is based on creating secure line between the client and server using Military grade encryption (AES-256) which is the most advanced encryption.
2. Zetsal App runs through SSL Protocol especially designed to act like HTTPs protocol to bypass firewall restriction so it can be used in China and countries that blocks VPN, its also uses the Military grade encryption (AES-256) which is the most advanced encryption.