Encrypt given data using rc4 cipher algo. RC4 is a stream cipher that generates a pseudo-random stream of bits used to encrypt data. RC4 was widely used in protocols like SSL/TLS and WEP due to its speed and simplicity but was eventually found to have severe security flaws. RC4 is no longer considered secure due to biases in its output and vulnerabilities that can be exploited in modern cryptanalysis. Our encryption process prepends the IV string used during the encryption process in the encrypted data so that it can be used during decryption.