Currently Verge.io supports the following auth sources based on the OAuth 2.0 protocol.
Two-factor authentication is an option that provides an added layer of security for user logins. When two-factor authentication is enabled login requires authorization via the user's email address in addition to valid username and password. The first time a user initiates login from a new device, a security code is emailed to the user's email address. This code then must be entered to complete the login process. Optionally, the user can select to store the security code on the local device, for automatic retrieval on subsequent login actions from the same local device. (This function is intended for personal devices, such as a user's home computer, personal laptop, cellphone, etc.)