Decomposed soft sets and soft encryption

In this thesis, we first introduced soft sets and soft set operations. Soft set theory was introduced by Molodtsov in 1999 to deal with problems involving uncertainty. Since then, soft sets have been applied to many areas, especially decision-making applications. We then defined decomposed soft sets by dividing the set on which soft sets are defined into equivalence classes. For this purpose, we gave the basic definitions and theorems related to equivalence relations and equivalence classes with their proofs as a separate section. We then defined soft encryption based on decomposed soft sets. The soft encryption we have newly defined is a more complicated type of Caesar encryption. Encryption is the process of making data or information unreadable using a certain algorithm. This process is of vital importance for ensuring information security in the digital world. Encryption plays a critical role in every situation where data must be transmitted, stored and processed securely. Encryption is one of the most effective defenses against cyber-attacks for both individual users and institutions. After doing the mathematical modeling of soft encryption, we wrote the computer program using the Python programming language. Finally, we finished the thesis with the conclusion section where we gave information about the place and future of soft encryption in existing encryptions.