For data storage and protection, encryption is an important standard. A secret key is required in order to encrypt or decrypt data. This key is typically located in memory, where it can potentially be stolen. In order to avoid this, new methods of generating secret keys have been developed. To safeguard the generation of the secret key, one of these techniques is to utilise a Physically Unclonable Function (PUF). In order to generate secret keys or simple authentication protocols, secrets can be extracted from the physical structure of the device. A stable PUF output is essential for generating cryptographic keys with greater uniqueness, randomness, and uniformity. The goal is to offer device identification methods that are inexpensive, efficient, and safe, as well as secure cryptographic key creation using PUFs. This paper propose a design that combines ring oscillator puf (ROPUF), Arbiter puf (APUF) and Exclusive OR gate. Verilog simulation is performed using VIVADO software. AES algorithm is implemented for encryption and decryption for cryptographic key generation. The experimental results shows the uniqueness, reliability, uniformity and aliasing has improved.