VyprVPN for Android establishes a connection using the OpenVPN 256bit, or 160bit protocols which is popular due to:
OpenVPN 256 use high encryption for better security and performance
OpenVPN 160 uses slightly less encryption for better speeds and performance
VyprVPN for Android also includes the option to connect via the Chameleon protocol. More information on Chameleon can be found here.
If you need any further assistance, please contact support.