An email access control scheme capable of resolving problems of the real
email address and enabling a unique identification of the identity of the
user while concealing the user identification is disclosed. A
personalized access ticket containing a sender's identification and a
recipient's identification in correspondence is to be presented by a
sender who wishes to send an email to a recipient so as to specify the
recipient as an intended destination of the email. Then, accesses between
the sender and the recipient by verifying an access right of the sender
with respect to the recipient according to the personalized access ticket
at a secure communication service. Also, an official identification of
each user by which each user is uniquely identifiable by a certification
authority, and an anonymous identification of each user containing at
least one fragment of the official identification are defined, and each
user is identified by the anonymous identification of each user in
communications for emails on a communication network.