The deployment of wireless sensor networks (WSN) in an untended environment and the openness of the wireless channel bring various security threats to WSN. The resource limitations of the sensor nodes make the conventional security systems less attractive for WSN. Moreover, conventional cryptography alone cannot ensure the desired security against the physical attacks on sensor nodes. Physically unclonable function (PUF) is an emerging hardware security primitive that provides low-cost hardware security exploiting the unique inherent randomness of a device. In this article, we have proposed an authentication and key sharing scheme for the WSN integrating Pedersen’s verifiable secret sharing (Pedersen’s VSS) and Shamir’s secret sharing (Shamir’s SS) scheme with PUF which ensure the desired security with low overhead. The security analysis depicts the resilience of the proposed scheme against different active, passive and physical attacks. Also, the performance analysis shows that the proposed scheme possesses low computation, communication and storage overhead. The scheme only needs to store a polynomial number of PUF challenge-response pairs to the user node. The sink or senor nodes do not require storing any secret key. Finally, the comparison with the previous protocols establishes the dominance of the proposed scheme to use in WSN.