Many methods of cryptography are available nowadays. They are used in several situations such as financial processing system, electronic commerce and electronic data interchange. Each has its own specific purpose and implementation algorithm. But no one is without any disadvantage even the best policy is carried on. The thesis proposed a method based on Fuzzy Theory to improve the information security by increasing the complexity of decryption for fuzzy-based encryption source data. The simulation results of security quality are better than former cryptographies as in this paper. Thus, the fuzzy-based encryption algorithm can be used in cryptosystem if needed.