Riddle

It's true I bring serenity,
And hang around the stars
But yet I live in misery;
You'll find me behind bars
With thieves and villains I consort
In prison I'll be found
But I would never go to court,
Unless there's more than one
 
The person who makes it, sells it. The person who buys it never uses it and the person who uses it doesn't know they are. What is it?
 
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