Reason behind choosing this model is the security and efficiency. Most interesting thing in this technique is the combination of two different techniques. Basically this technique is a method of encryption that combines two or more encryption technique and usually includes a combination of substitution and symmetric key encryption algorithm like AES to take the benefits of the strengths of each type of cryptographic technique.RGB substitution provides better security as it is changing the format of the plain text and confuses the intruder that weather transmitted data is a form of image or it is some other secure information.