Now-a-days as the trend is to go online in every field like E-commerce, Banking, security is one of the main concerns. Some of this information additionally incorporates delicate data such as personal information or top secret government documents. So it is very important to protect personal data and information. Only DES or IDEA may be attacked by different sorts of cryptanalysis utilizing parallel procedure. In this paper, the author implements a symmetric key algorithm combining with two symmetric key algorithms, i.e. IDEA and 3DES with some modifications in order to improve the security and make it more complex for the attackers to break this algorithm. Using the combinations of these keys, we get 2^ (56+128) =2^184 that is 3.32 times stronger than conventional DES and 1.44 times stronger than conventional IDEA algorithm. The recommendation of S-IDEA algorithm is that it likewise be actualized in equipment utilizing VLSI innovation.