What is the impact of not having sessions.NewCookieStore key rotation?

[tintinnabulate]

Do we need to use the github.com/gorilla/sessions key rotation?

At the moment, we don't have it. Write a test to assess the impact of not having rotation of store and encryption keys, and if it's not a problem, leave it. If it is a problem we may need to add it as per the example on http://www.gorillatoolkit.org/pkg/sessions

var store = sessions.NewCookieStore(
    []byte("new-authentication-key"),
    []byte("new-encryption-key"),
    []byte("old-authentication-key"),
    []byte("old-encryption-key"),
)