Plugin inserting user password into another table to

Well i got some problems with my plugin.

the thing i want to do is to make a plugin that also register the user into another table for example i make a user test with password test that it inserts that user into another table to but under another encryption

i know the password that’s generated at registering is $user_pass = wp_generate_password(); but i don’t know how i can use this password in a plugin.