New returns a signed authentication cookie for the given login, expiration time, and secret key. If the login is empty, the function returns an empty

Login returns a valid login extracted from the given cookie and verified using the given secret key. If verification fails or the cookie expired, the

Parse verifies the given cookie with the secret key and returns login and expiration time extracted from the cookie. If the cookie fails verification

NewNoPadding is like New but returns cookie encoded without base64 padding characters.

NewSinceNow returns a signed authetication cookie for the given login, duration since current time, and secret key.

NewSinceNowNoPadding is like NewSinceNow but returns a cookie without base64 padding characters.