As of my last update in July 224,the top popular and secure VPN apps for Android are:

1. VPN Pro (Version 2..5): A highly secure and feature-rich VPN with a user-friendly interface.

2. Ophidia (Version 1.5.8): Known for its balance between security and usability, with a strong reputation for fast speeds.

3. Voxie (Version 2..4): Offers a good balance of speed and security, with a clean design.

4. Pylan (Version 2..4): Known for its fast and reliable performance, with a focus on encryption.

5. Vsec (Version 1.2.3): Uses a strong encryption algorithm and is known for its security features.

These are some of the most popular and secure VPN apps available for Android. You can explore more based on your specific needs, whether you prefer speed, security, or ease of use.