Sign Up Process

The brief process of signing up is that the user submit the form which contains the email address and password. The server should send the an activation email to the user. The email content should contain a link which has the activation code. After the user clicks the link, user's account will become active. active

For the email verification, the verification token(i.e. activation code) must meet following criteria:
-It must link back to the User (via a unidirectional relation)
-It will be created right after registration
-It will expire within 24 hours following its creation
-Has a unique, randomly generated value

The detailed steps of signing up are shown as below:

Technical points
Password encryption

The detailed steps of user activation are shown as below:

Technical points
Java send email