In the era of digital transaction, in order to transact the data in a more secured manner the need for a cryptographic algorithm is inevitable. There are numerous numbers of cryptographic algorithms which makes the system invulnerable from the attacks of intruders and eavesdroppers.RivestCipher4 algorithm is one such cryptographic algorithm which is very well known for its performance and simplicity. In this paper, we propose a software toolkit for increasing the key strength so that it will be very hard for the intruder to break the key and this technique will act as black box so that intruder will have no idea about the key formation. So it will lead to increased key complexity which obviously results the intruder nothing else than confusion and frustration.