Section 1 New Techniques

**Chapter 1**

**Abstract**

Hybrid Encryption Model Based

*Amal Hafsa, Mohamed Gafsi, Jihene Malek*

*and Mohsen Machhout*

with more simplicity and correctness.

**1. Introduction**

**3**

on Advanced Encryption Standard

and Elliptic Curve Pseudo Random

Securing multimedia applications becomes a major challenge with the violation of the information increasing currently. In this paper, a novel method for color image encryption is proposed. The procedure of encryption is performed using cooperation between Elliptic Curve Cryptography (ECC) and the Advanced Encryption Standard (AES) with CTR (Counter) mode. In the cryptographic system, we have proposed to take advantage of the Elliptic Curve Random Generator to generate a sequence of arbitrary numbers based on the curve. The random generation step is founded on the public key sharing and a changing point G. Then, the AES-CTR is performed to these sequences using arbitrary keys for image encryption. The use of the AES alongside greatly distributed random results an interesting encryption method. Security analysis is successfully performed and our experiments prove that the suggested technique provides the basis of cryptography

**Keywords:** hybrid scheme, AES, CTR ECC, random generator, image encryption

Cryptography plays an important role to attain the privacy of images. There exist two main families of cryptographic algorithms. The asymmetric algorithm is inherently slow because of its associated hard calculations, while the symmetric algorithm shines with its rapidity. However, the latter suffers from a serious gap, the keys must be transmitted safely. To overcome these issues, we suggest an efficient version of AES-ECC hybrid encryption scheme which combines the benefits of the symmetric Advanced Encryption Standard (AES) and the asymmetric Elliptic Curve Cryptography (ECC). In [1], C. Junli el al propose an image encryption method using the AES-ECC hybrid cryptographic system. In that paper, the authors focus on the key sharing way. In fact, the AES key encryption is performed using ECC and the securing key is done by the digital signature of the ECC. Then, the AES is utilized for data encryption. An ameliorated version of this way is suggested in [2], an AES-ECC hybrid encryption system is developed for wireless sensor network. In this way, the AES Key is generated and encrypted by the ECC algorithm. After transmission, another pair of the ECC key (Key 2) is generated and ciphered using the symmetric algorithm. This token is transferred to the other part

#### **Chapter 1**
