shva in Gmail

Dear Readers,

I am not sure whether you have noticed this or not. If NO then check it right away. If you are Gmail user then when you login to your account you might notice this as shown below. This is unique for everyone.

Have you every wondered what is this? Is it an acronym? Or Is it a secret word if so why it's unique? Many questions raises if we start thinking. Let's pause and see what exactly it is. 

As per Mike Sego ( Gmail Frontend Engineer, 2005-2007) "shva" is an acronym for "should have valid authentication"

Upon successful authentication of your credentials shva is populated.