Security is a concept similar to being cautious or alert against any danger. Network security is the condition of being protected against any danger or loss. Thus safety plays a important role in bank transactions where disclosure of any data results in big loss. We can define networking as the combination of two or more computers for the purpose of resource sharing. Resources here include files, database, emails etc. It is the protection of these resources from unauthorized users that brought the development of network security. It is a measure incorporated to protect data during their transmission and also to ensure the transmitted is protected and authentic. Security of online bank transactions here has been improved by increasing the number of bits while establishing the SSL connection as well as in RSA asymmetric key encryption along with SHA1 used for digital signature to authenticate the user.