Recently the engineering community began to seek the possibly application of chaos. The fact that the cryptographic community had used discrete pseudo-chaotic systems for a long time to generate cipher keys that leads to the initiation of applying chaos to secure communications. This paper presents a schematic design methodology for a fuzzy observer based secure communication of hyper chaotic systems in cryptographic applications. The transmitter and receiver, which are based on a 3D hyper chaotic oscillator, are synchronized by exploiting the concept on the observer from the control theory. The scalar transmitted signal is designed so that the hyper chaotic carrier masks the encrypted signal, which in turn hides the message signal. To encrypt the message signal, an n-shirt cipher with multiple key algorithms is proposed. In receiver side, the fuzzy observer of chaotic system is designed based on the general Takagi-Sugeno fuzzy model. This approach leads to the design of communication systems with higher security.