# Functions
GenAuthHeaderKey generates a authentication header value.
NewHelper returns a new instance of AuthHelper.
# Variables
ErrAuthHeaderHasInvalidLen = auth header has invalid length.
ErrAuthHeaderInvalid = auth header is invalid.
ErrAuthHeaderInvalidFormat = auth header has invalid format, expect \"Basic keyID:sha512(Key)\".
ErrAuthHeaderNotBasic = auth header expected to be \"Basic ...\".
ErrNoAuthHeader = no authorization header.