Patent ID: 9439072
Filing Date: 2016-09-06
CPC Classification: H04L,H04W

Claim Text:
1. A method for authentication comprising: receiving a subscription request from a user terminal, the subscription request including a group code and a plaintext e-mail address; storing the plaintext e-mail address included in the subscription request in a table for subscription; when the group code and the plaintext e-mail address correspond to each other, performing a group authentication procedure on the user terminal; when the group authentication procedure for the user terminal is successful: issuing an authentication key for the subscription request and storing the authentication key in the table for subscription; transmitting the authentication key to the user terminal; receiving, from the user terminal, member information including an encrypted plaintext e-mail address of the user with the authentication key; searching the plaintext e-mail address using the authentication key in the table for subscription; encrypting the searched plaintext e-mail address using a same encryption logic used when an encrypted e-mail address recorded in the table for redundancy removal is encrypted ; and checking whether the encrypted searched plaintext e-mail address exists in a table for redundancy removal; when the encrypted searched plaintext e-mail address exists in the table for redundancy removal, transmitting a redundancy message to the user terminal; when the encrypted searched plaintext e-mail address is not in the table: issuing a member session key and e-mail session key; storing the encrypted searched plaintext e-mail address and e-mail session key in the table for redundancy removal; storing the encrypted plaintext e-mail address in the member information and the member session key in a table for members; transmitting the member session key and the e-mail session key, to the user terminal; and deleting data of the table for subscription for the subscription request; and providing a service requested by the user terminal in response to a service request including the member session key and the e-mail session key when the member session key is in the table for members and the e-mail session key is in the table for redundancy removal.