Password protected video I want to protect my instructional video with a password. There is a use case. 

When a user wants to play an encrypted file (update: file located on user's android device), the encrypted file will pop up a dialog box to request the user to enter a Playback Password. This dialog box will display the machine ID of the user's android device. The user can send his/her own machine ID to you, and you can create a Playback Password based on the user's machine ID. After that the user can use this Playback Password to play your file on his/her device. Since the Playback Password is created based on the user's machine ID, the user will not be able to share the Playback Password with other users. Since the Playback Password is bond to the user's device, the user will not be able to re-distribute your files. 

Is there some software that helps me to obtain this purpose?



I seem to have secured the streaming video from the web site well enough, but a lot of the members want video files on their devices because they don't want to have to deal with wi-fi to play the video while they conduct the class. (update: I'm not good in English. I meant file need to be located on user's android device. No streaming)



There is no doubt someone can just shoot the video from the screen, but I want to slow down the proliferation of my video.
What about an app like Android Video Protector? It is advertised as being exactly what you're looking for:

How to protect video files on Android Platform?
Android Video Protector Solution contains two software, there are Android Video Protector and PPVM Video Player. Android Video Protector is a video encryption software running on Microsoft Windows Operating System, it uses a password to encrypt the video you hope to protect, and supports 4 types encryption modes:

Device Binding, One Device, One Password
Non Device Binding, All Device, One Device ID, One Password
Non Device Binding, All Device, One Password
Encrypt video only

How to playback the encryption video on Android Platform?
Because the video is encrypted, the general video player can't playback this video, PPVM Video Player is the player running on
Android Platform and supports playback the encryption video. it
firstly check the playback password, which can be generate using
Android Video Protector, after complete the password authentication,
it will playback the encryption video.

I have no idea if these programs are reputable or if they work. The Android app is a direct download from their website (not the Google Play store) - proceed with caution at your own risk.