Authenticate User from Java application using JDBC

Hello everyone,

I'm trying to authenticate a user(Health Share clinician) from a Java Application. 

I 'm already connected to Caché and able to run SQL commands.

My question is: How can I authenticate a user using only SQL? In fact, what I want is verify if the users exists in the base and if the given password is the same used in Health Share.

There is a column 'password' in Security.users table but I'm not able to see its content, even so, I don't know which hash function to use to compare with.