Text Steganography using Extensions Kashida based on the Moon and Sun Letters Concept

Abstract

Existing steganography methods are still lacking in terms of capacity. Hence, a new steganography method for Arabic text is proposed. The method hides secret information bits within Arabic letters using two features, which are the moon and sun letters and the redundant Arabic extension character “-” known as Kashida. The Arabic alphabet contains 28 letters, which are classified into 14 sun letters and 14 moon letters. This classification is based on the way these letters affect the pronunciation of the definite article (ال) at the beginning of words. This method uses the sun letters with one extension to hold the secret bits ‘01’, the sun letters with two extensions to hold the secret bits ‘10’, the moon letters with one extension to hold the secret bits ‘00’ and the moon letters with two extensions to hold the secret bits ‘11’. The capacity performance of the proposed method is then compared to three popular text steganographic methods. Capacity is measured based on two factors which are Embedding Ratio (ER) and The Efficiency Ratio (TER). The results show that the Letter Points and Extensions Method produces 24.91% and 21.56% as the average embedding ratio and the average efficiency ratio correspondingly. For the Two Extensions ‘Kashida’ Character Method, the results for the average embedding ratio and the efficiency ratio are 56.76% and 41.81%. For the Text Using Kashida Variation Algorithm method, the average embedding ratio and the average efficiency ratio are 31.61% and 27.82% respectively. Meanwhile, the average embedding ratio and the efficiency ratio for the Proposed Method are 61.16% and 55.70%. Hence, it is concluded that the Proposed Method outweighs the other three methods in terms of their embedding ratio and efficiency ratio which leads to the conclusion that the Proposed Method could provide higher capacity than the other methods.