Résumé
In this paper, we are particulary interested by image protection. The conventional encryption standard may be not applicable to images, due to the digital images properties which are characterized with some intrinsic features such as highly pixel redundancy and correlation. We propose a new asynchronous stream cipher based on generalized continued fraction (GCF). The proposed scheme is resistant to statistic attack, differential attack and some other known attacks. Experimental results prove that our scheme is efficient and secure.