The dissertation titled” Encryption/Decryption Tool with Cryptanalysis” is based on the concept of cryptographic system. We have implemented a set of encryption/decryption methods which include Hill Cipher, Caesar Cipher and Transposition Cipher & RSA. These methods are used to convert a given text into secret code it to another user & vice-versa. Further another possibility of finding out a text when a secret code is found out without knowing about the key, the sender has used to encrypt it. Hence we provide a way for encryption, decryption and an attack on any file and thus get the way for a secured communication between users.