Improving Security of Crypto-Steg Approach using Time Sequence Dictionary and Modifying Spacing Techniques

Abstract

Cryptography and steganography are significant tools for data security. Hybrid the cryptography with Steganography can give more security by taking advantage of each technique. This work has proposed a method for improving the crypto-stego method by utilizing the proposed dictionary method to modified ciphertext then hiding modified encrypt ciphertext in the text by used the proposed modified space method. For cryptography, we have been utilized an advanced encryption standard (AES) to the encrypted message, The AES algorithm is utilized a 128bit Block Size and 256bit key size. The ciphertext characters is then replaced by the characters identified by dictionary list. The dictionary is time-dependent, where each of the equivalent words will shifting based on the time-shift equation. The modified ciphertext is then embedded into a cover text so that the attacker cannot separate them by applying cryptanalysis. The “Modifying Spaces” method used “Spaces” to build a steganography tool that hide the secret message.
 The experimental results show that the proposed method has achieved high-security level when combined cryptography and steganography in such way that the ciphertext is changed to another value by a used dictionary with time sequence that makes cryptanalysis test failed to guess and identify the algorithm that been used for encryption. The stego. test shows the proposed method achieved good results in term of capacity and visibility which is approved it hard to notice. The tests also approved that the proposed methods run fast with a less computational requirement.