ci_session is it secure and other questions

Hello!
I was wondering about 2 questions.
1. Is the ci_session (sess cookie name) secure?
2. If I try to add a prefix to it like __Secure, it breaks the URL. Example index(login) will then route me to localhost/dashboard/localhost/dashboard/index. Why is this? What in the ci_session control's this? 

Thank you for your time.

1. I have no idea what you are worried about.
2. I cannot reproduce.

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