Abstract :
TCP sockets are abstractions that applications use to send and receive data through connections between two hosts in a computer network. Networks commonly used by public users who are very vulnerable to data tapping. This problem can be overcome by using a cryptographic algorithm on the TCP socket, one of which uses the RSA algorithm. The level of security of the standard RSA algorithm has security on public or private keys originating from input 2 prime during key generation. Several studies have been conducted to develop the RSA algorithm, but the results of this study make the performance of the RSA algorithm faster. Improved performance can use LCG RNG on RSA key generation. RNG LCG has the main advantage in terms of speed. LCG RNG can generate prime numbers that come from input names that are not found in other RNG. The results of the performance test of key generation, encryption, decryption with character lengths ranging from 40 to 81920 showed that RSA improvisation using RNG LCG in terms of better performance using the RSA algorithm. Security testing using known plaintext attacks and skin factorization shows the RSA improvisation algorithm using RNG LCG in terms of security is better using the RSA algorithm. The sniffing test still has a gap in the TCP socket.