What modules are using the query term "token" for access control?

[Eliezer Croitoru]

I have seen that couple media sites are using the "token" query term for 
access control to some media content and I was wondering what module can 
do that?
For examples the request:
http://example.com/media/111111.mp4?token=xyz_very_long_token

allows access to only this 111111.mp4 specific file and not to 111112.mp4 .

I can write a web application that does the same thing but was wondering 
what might be used if there are couple web servers and couple content 
servers. In this specific case the token should be either shared between 
the servers or that the token has some encrypted data in it.
Are there any modules that implements this function?

Thanks,
Eliezer