This document provides a literature review of modern variants of the RSA cryptosystem. It discusses several variants proposed in other research papers that aim to address weaknesses in the original RSA algorithm, such as improving security against fault-based attacks. The document analyzes the merits and drawbacks of each variant, such as increased computation time or improved security levels. It concludes that RSA remains very popular for encryption and decryption due to its strong security with large key sizes, and more research is still needed to develop variants with even stronger security.