Pengamanan Citra Dengan Kombinasi Modified Serpent IWT Dengan Modified Logistic Chaotic Map

Abstrak Algoritma kriptografi dapat digunakan untuk mengamankan citra. Salah satu algoritma kriptografi yang dapat digunakan untuk mengenkripsi citra adalah algoritma Serpent. Namun, algoritma Serpent memerlukan proses enkripsi dan dekripsi yang lama. Selain itu, pengenkripsian saja tidaklah cukup karena akan menimbulkan kecurigaan sehingga informasi akan rentan dicuri. Maka diperlukan teknik steganografi seperti metode Integer Wavelet Transform (IWT). Citra rahasia akan dienkripsi terlebih dahulu dengan menggunakan metode Modified Serpent, dimana modifikasi Serpernt mengubah proses transformasi substitusi byte (DES S-box) menjadi list bilangan prima 257 yang memiliki 128 generator untuk digunakan sebagai kunci di setiap putarannya. Pada proses penyisipan dengan metode IWT, perlu ditentukan posisi bit dan piksel pada cover image yang akan disisipkan sebuah pesan. Untuk menentukan posisi tersebut, maka digunakanlah fungsi chaos. Setelah itu, dapat dilakukan proses ekstraksi terhadap citra stego yang dihasilkan pada proses penyisipan untuk memperoleh kembali bit yang tersimpan didalamnya. Kumpulan bit tersebut dapat didekripsi sehingga akan diperoleh kembali citra rahasia semula.

Chaos Based Image Encryption Scheme Using One Dimensional Exponential Logistic Map

The widespread use of images in various sectors of life makes its protection increasingly necessary and important. An improvement over encryption and decryption algorithm using exponential logistic chaotic map was proposed. In this work, we adopt an encryption/decryption strategy for colour images using the exponential logistic chaotic map. The proposed encryption/decryption algorithms are implemented in MATLAB for computer simulation. The experimental results indicate that the proposed algorithms can be used successfully to encrypt/decrypt images with secret keys. The performance analysis using histogram uniformity analysis and correlation coefficient show that the algorithms give larger space, quick speed and easy to realize. The encrypted images have good encryption effect and low correlation coefficient rendering it a good candidate for confidential and secure means of transmitting image information in untrusted networks.

A Chaos based image Encryption Scheme using one Dimensional Exponential Logistic Map.

The widespread use of images in various sectors of life makes its protection increasingly necessary and important. An improvement over encryption and decryption algorithm using exponential logistic chaotic map was proposed. In this work, we adopt an encryption/decryption strategy for colour images using the exponential logistic chaotic map. The proposed encryption/decryption algorithms are implemented in MATLAB for computer simulation. The experimental results indicate that the proposed algorithms can be used successfully to encrypt/decrypt images with secret keys. The performance analysis using histogram uniformity analysis and correlation coefficient show that the algorithms give larger space, quick speed and easy to realize. The encrypted images have good encryption effect and low correlation coefficient rendering it a good candidate for confidential and secure means of transmitting image information in untrusted networks.