Cryptography: What is secure?

As we moved into the information society, cryptography has become increasingly used to provide security. What is secure today can be broken tomorrow or be broken by 'something' or 'somehow'. This rule could just be the only rule that never changes in the ever-changing game of security. It is thus important for security personals to know more than just applying cryptography blindly. This paper looks at how security is achieved by discussing basic substitution and transposition operations to get an appreciation of security in cryptography and recommend basic approach to implement cryptography. It is beneficial for readers to have some knowledge on cryptography to follow certain discussions of the paper.