Creating the Register and Login Methods

3 February 2019

Creating the Register Method

With the GUI made, we now need users to be able to register so that they can use the program. This involves the user entering their email and creating a password. We need to store this data in the database on the users table. Before we can do that, we need to hash the password with a salt for security reasons. Once hashed, we use another SQL statement to store the data.

INSERT INTO users(email,password,salt) VALUES(?,?,?)

VALUES(?,?,?) The question marks act as a placeholder. This means that, using the sqlite-jdbc library, we can replace them with the corresponding data. INSERT INTO users(email,password,salt) means add the corresponding data as specified by VALUES to the columns (listed in between the brackets) in the table called users. So now the user’s data is stored in the database and they will be able to login.

Creating the Login Method

Now that users can register with the program, they have to be able to log in. This involves the user entering their email and password on the GUI and clicking the login button. On clicked, the program uses yet another SQL statement to search for the entered email in the database.

SELECT password,salt FROM users WHERE email=?

This returns the corresponding hashed password and salt, if the entered email exists in the table users. Otherwise, it returns nothing. Notice the ? which works in the same way as the statement above.

If the email is found, we have to hash the entered password using the salt retrieved from the database and compare it to the hashed password retrieved from the database. If the hashes match we log the user in, otherwise we display a suitable error message.