Hotspot Shield is a free, ad supported app that encrypts your web browsing when you're using WiFi connections in Vietnam. Once you install and enable Hotspot Shield on your laptop, the software encrypts your traffic and courses it through its own data center tunnel, bypassing Vietnam's firewalls.

Limitations: it's ad-supported, so you see ads on your browser window. The software also imposes a 5 GB transfer limit.

Hotspot Shield - Download Page