Security of data communications between embedded arduino systems with substitution encryption

Arduino has the main component of AVR type microcontroller. In microcontroller there are microprocessor, memory and input / output devices that are integrated with each other. So to execute it required a series of programs. While the ability Arduino now can communicate with each other through serial communication. On the other side the need for communicating security is required. But the computing capabilities and storage space of the program is limited, so becomes a consideration to use a suitable encryption technique. The Arduino type used was Arduino Uno and the encryption technique was substitution. The substitution encryption technique was applied for data communication security between Arduino Uno worked well. This was evidenced by the results obtained from experiments using the Proteus software simulation. It used two Arduino Uno devices with one way asynchronous serial communication as the connections. While the software to created substitution encryption and uploaded it to each Arduino Uno be using AVR Basic Compiler software. The selection of substitution encryption keys were generated randomly so not understood. The encryption and decryption key form must be the same. So the data sent is same contents with the data received and cipher text appear among them.