Abstract: In every organization, use of online services is increasing. With this the sensitive data is carried over internet on daily basis. Hence, there is a chance of misleading the data by unauthorized parties. So, there is need to provide security for that data and cryptography is the science that helps in providing security. By using cryptography different types of security algorithms have been developed. Three fish is a symmetric-key and tweakable block cipher algorithm designed as a part of the skein hash function. The strength of three fish encryption relies on 128-bit tweak value. The proposed work focuses on strengthening Encryption Process by implementing tweak buffer along with input. Whereas key scheduling is secured by applying SHA-256 algorithm. SHA-256 is a secured hash function which belongs to SHA-2 family. Three Fish is used in providing security on software and hardware. It is also implemented in electronic media such as transactions like banking.