<p>In this manuscript, an authentication algorithm based on three phase only masks on interference algorithm using elliptic curve cryptography and sparsification in the fractional Hartley domain is proposed. The proposed algorithm strengthens the security of three POMs-based interference algorithms which are vulnerable to iterative cryptographic attacks. The cascaded use of fractional Hartley transform and interference algorithm contributes to a larger keyspace in the proposed cryptosystem. The efficacy and robustness of the proposed authentication algorithm is validated through simulations on binary and grayscale images. The proposed authentication method was tested using multiple statistical analyses, such as correlation coefficients, entropy calculations, error metrics, distribution assessments, and visual representations like mesh plots and histogram. To access its robustness, the cryptosystem was evaluated in the presence of practical disturbances like noise. Moreover, the security of the proposed cryptosystem is also tested against available iterative and plaintext based cryptographic attacks. Experimental results demonstrate the security of the proposed cryptosystem, making it viable for authentication.</p>