For secure and reliable data transmission over the network from unauthorized users in a Communication system, there are various type of cryptographic algorithm has been introduced but RSA is the most famous cryptographic algorithm in these entire cryptographic algorithm. It involves the encryption decryption key generation. In this paper we provide a modify RSA algorithm based on the n prime no. and bit stuffing. Security of RSA is mainly depends on factorization. In this technique we use n prime no. because large prime numbers are not easily factorized and bit stuffing provide extra layer of encryption by which we provide maximum security and efficiency for data over the network.