A network authentication method to be implemented using a network server, a network authentication device and a user device for authenticating the user device, the user device storing a terminal program and including a plurality of hardware components each of which has a unique identification code, said network authentication method being characterized by the following steps of: a) configuring the network authentication device to store hardware information (10a-10c) associated with the identification codes of the hardware components of the user device; b) when it is intended to verify identity of the user device in response to a login request from the user device for accessing the network server through a first communication channel, configuring the network server to redirect the user device for connecting with the network authentication device through a second communication channel that is separate from said first communication channel, and configuring the user device to execute the terminal program for scanning the hardware components thereof to obtain the identification codes of the hardware components of the user device, for establishing a hardware list according to the identification codes of the hardware components thus obtained, and for sending to the network authentication device verification data that is associated with the hardware list; c) configuring the network authentication device to verify identity of the user device based on relationship between the verification data received from the user device in step b) and the hardware information (10a-10c) stored in step a); d) configuring the network authentication device to generate a key according to the hardware information (10a-10c) stored therein, and to send the key to the user device and the network server; e) when the user device intends to conduct an electronic transaction with the network server, configuring the user device to generate a first digital signature corresponding to transaction data of the electronic transaction using the key sent by the network authentication device and to send the transaction data and the first digital signature to the network server, and configuring the network server to generate a second digital signature corresponding to the transaction data received from the user device using the key sent by the network authentication device; and f) configuring the network server to compare the first digital signature from the user device with the second digital signature generated thereby, and to determine that the transaction data was not tampered during transmission from the user device to the network server when the first digital signature conforms with the second digital signature. a) configuring the network authentication device to store hardware information (10a-10c) associated with the identification codes of the hardware components of the user device; b) when it is intended to verify identity of the user device in response to a login request from the user device for accessing the network server through a first communication channel, configuring the network server to redirect the user device for connecting with the network authentication device through a second communication channel that is separate from said first communication channel, and configuring the user device to execute the terminal program for scanning the hardware components thereof to obtain the identification codes of the hardware components of the user device, for establishing a hardware list according to the identification codes of the hardware components thus obtained, and for sending to the network authentication device verification data that is associated with the hardware list; c) configuring the network authentication device to verify identity of the user device based on relationship between the verification data received from the user device in step b) and the hardware information (10a-10c) stored in step a); d) configuring the network authentication device to generate a key according to the hardware information (10a-10c) stored therein, and to send the key to the user device and the network server; e) when the user device intends to conduct an electronic transaction with the network server, configuring the user device to generate a first digital signature corresponding to transaction data of the electronic transaction using the key sent by the network authentication device and to send the transaction data and the first digital signature to the network server, and configuring the network server to generate a second digital signature corresponding to the transaction data received from the user device using the key sent by the network authentication device; and f) configuring the network server to compare the first digital signature from the user device with the second digital signature generated thereby, and to determine that the transaction data was not tampered during transmission from the user device to the network server when the first digital signature conforms with the second digital signature.