Mobile and embedded devices are becoming inevitable parts of our daily routine. Similar to other electronic devices such as read access memory (RAM) and storage, mobile devices require to authenticate and to be authenticated in a secure way. Usually, this can be accomplished by servers which possess private information for all devices. Since these devices are inherently mobile and operating in untrusted environments, they are prone to be accessed by untrustworthy users. Physical unclonable function (PUF) is a unique physical feature of a semiconductor device such as a microprocessor that can be generated from physical conditions such as supply voltage, temperature, etc. Ring oscillators are the principal parts of PUFs that are synthesized on a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). Password manager systems are used in order to keep a database of usernames and password for clients in order for registration and authentication. This table plays a crucial role in authentication in many systems. Hence, security is one of the important features of these systems. Normally, in these tables only usernames and passwords are stored; however, they are vulnerable to many attacks. So, the first method of enhancing the security is using the hash instead of the original data, but, advanced hackers can break these hash data again. Hence, the method that we are going to use in this project is utilizing PUF to store the challenge of each user instead of saving the hash of passwords.