#some_node.gd

func store_password(user: String, password: String) -> void:
    if password.is_empty() or user.is_empty():
        print("Trying to store non valid credentials.")
        return

    Keyring.set_password("my_cool_application", "credentials", user, password)

func login(user: String) -> void:
    var password := Keyring.get_password("my_cool_application", "credentials", user)
    if password.is_empty():
        return
    
    # Use password
    ...