Encryption and Decryption for Network Security Using Reverse Context-Free Grammar Productions

Abstract

An enhanced symmetric key cryptographic algorithm is presented in this paper. This new technique uses context-free grammar as it presents a unique property of cryptography which states that one can generate strings from a given grammar; but one cannot classify a grammar if provided with only the strings generated by it. The planned idea consists of four modules: encode, encrypt, decrypt, and decode. Firstly, the file is encoded by making use of the encoding techniques to obtain an intermediate text. The intermediate text is then encrypted to get the ciphertext file using context-free grammar along with the secret key. The secret key is generated by using random number generation algorithm. At the receiver’s side, the ciphertext file is then decrypted by making use of context-free grammar followed by decoding techniques to obtain the original file.