Abstract: An example technique is provided for authenticating a first communication session. The technique includes receiving an indication that a first network device has established a first communication session with a user-side device. A second network device authenticates the first communication session by establishing a second communication session via session initiation protocol (SIP) or voice over Internet protocol (VoIP) communication with the user-side device before the user-side device directs a user password to the first network device in the first communication session. Also, private identification information of the user is retrieved from a database and sent to the user-side device in the second communication session. The user-side device compares the private identification information received in the second communication session to locally stored private identification information to determine whether the received private identification information matches.

Abstract: A method, device and a system for verifying a communication session are provided. The method comprises: establishing another session with a user-side device at a network device or at another network device associated with the network device before providing proprietary information of a user in a communication session established between the user-side device and the network device; in the another session, sending private identification information of the user to the user-side device; wherein, the verification can be based on a determination by the user on the consistence between the received private identification information and private identification information previously set by the user.