International Association
for Cryptologic Research

This paper presents 'KEM Sphinx', an enhanced version of the Sphinx packet format, designed to improve performance through modifications that increase packet header size. Unlike its predecessor, KEM Sphinx addresses performance limitations inherent in the original design, offering a solution that doubles processing speed. Our analysis extends to the adaptation of KEM Sphinx in a post-quantum cryptographic context, showing a transition with minimal performance degradation. The study concludes that the trade-off between increased size and improved speed and security is justifiable, especially in scenarios demanding higher performance. These findings suggest KEM Sphinx as a promising direction for efficient, secure communication protocols in an increasingly post-quantum cryptographic landscape.