In the contemporary era marked by widespread internet accessibility, there has been a notable surge in online shopping activities, consequently giving rise to an increased prevalence of online payment transactions. The utilisation of credit cards for myriad purchase transactions has reached a staggering scale. As advanced AI tools and the penetration of e-commerce platforms continue to expand, concerns about privacy infringement and data breaches have become more pronounced. Consequently, it becomes imperative to implement payment processing mechanisms that prioritise the preservation of privacy, ensure secure transactions, and safeguard against data compromise in the event of a breach. While several methods have been used in the past to address these challenges, this study advocates for an enhanced and more robust transactional model. The proposed model employs various public cryptography algorithms and their function-hiding techniques to generate a one-time-use credit card number. This number is communicated to the user through a secure key-sharing algorithm, which is then used as the means of authentication for the transaction. Notably, the proposed approach ensures that third-party online vendors are separated from accessing the original credit card number while facilitating the authentication of the transaction. The security of the proposed method is assessed over two diverse cases when either of the participating entities act as an adversary. This novel approach aims to elevate the standards of security in online transactions, offering a pragmatic solution to the escalating concerns associated with privacy and data integrity.