An Enhanced Cryptographic Technique for Messages Traveling between Computers

In this work, a symmetric key cryptographic technique for encrypting/decrypting data is implemented with C language. The proposed technique is mainly intended for sending an email, a private instant messaging or text blocks. The plaintext for encryption/decryption is treated at the bit level which provides more security than mingling and mangling characters. In addition, the advantage of this technique is that both, the key algorithm which is generated from the plaintext stream bit and the encryption/decryption algorithm are the same. If we change a key from one encryption to another using the same plaintext, the ciphertext will be different. Errors in one or more bits of the ciphertext do not affect the future ciphertext blocks. The disadvantage is the security problem. Equal blocks in the plaintext become equal blocks in the ciphertext, which is easy to guess from the ciphertext that two blocks are the same.