# A Comparative Analysis of Arabic Text Steganography
## 4 Arabic Text Steganography
### Kashida Method  
Kashida refers to a type of justification, i.e., a stretch or extension of Arabic letters. It is used for various purposes such as emphasis, legibility, aesthetic, and justification [89]. In this steganography method, the extension (kashida) is added to words to represent the secret bit \"1.\" When it is not added, it represents the secret bit \"0.\" It is worth noting that alphabet extensions do not affect the writing content or the message content. Although the sentence in the output text still has the same meaning as the cover text, i.e., \"It is from the excellence of (a believer's) Islam that he should shun that which is of no concern to him.\", the appearance of the text changes and increases the file size. Thus, it may capture the reader's attention. The Kashida method's established state, which protects the secret bit in any letter, was performed by the authors of [90]. It needs the pointed letters with extension to hide secret bit \"1\" and the unpointed letters with extension to cover secret bit \"0.\" This method does not have any effect on the written content, as illustrated in Table 11. The improved work by the authors of [90], described in [91], involved injecting one kashida to hides \"0\" and employing two consecutive kashidas to conceal \"1.\"  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Authors** & **Methodology** & **Pros** & **Cons** \\ \hline \multirow{4}{*}{[80]} & Multiple embedding scenarios are & Low computational time. & \multirow{4}{*}{ \begin{tabular}{c} Stego text is fixed \\ for the use of only \\ 1 font type. \\ \end{tabular}  } \\  & achieved by changing the font & & \\  & style of diacritics. It considers & & \\  & repeated but invisible dacritics. & Improved invisibility. & 1 \\  & & Improved security using RLE. & 1 \\  & & Low computational time. & \\  & & Embedding is automated or & \\  & & manual. Stego file has a flexible & \\  & & format. & \\  & & & \\  &  
Building on this method, a stego system for Arabic e-text, Maximising Steganography Capacity Using Kashida in Arabic Text (MSCUKAT), was developed [92]. At the same time, the algorithm proposed by the authors of [77] hides the secret message as numbers by inserting kashidas. Each extendable letter can hide a specific number based on the position and the number of kashida in a word. Later, the implementation of MSCUKAT was produced by the authors of [93]. The algorithm proposed by the authors of [73] considers four scenarios where kashida letters can be added. Techniques are employed at random for selecting one of the four scenarios in each round. Then, message segmentation principles enable the sender to select over one strategy for each message block. Similar to the method described by the authors of [73], four embedding schemes were designed by the authors of [94] to hide two secret bits. The suggested design utilizes the existence of kashida after a pointed or unpointed letter to hide the secret bits. Next, the authors of [95] compressed secret messages using Gzip and encrypted these compressed secret messages by deploying AES. The proposed embedding method involves four stego options: Pointed kashida (After Letters), pointed kashida (Before Letters), pointed kashida (Mixed Letters), and MSCUKAT. Another work [96] hid a voice file into a text file using kashida and the word \"La.\" The proposed embedding algorithm reduces the size of the secret voice using the Loss-Less compression algorithm. It then hides \"1\" by inserting kashida after the letters, while \"0\" is hidden by leaving the letters without kashida insertion. Using the sun and moon letters, a technique proposed by the authors of [67] protects a secret bit in Arabic script. The technique considers four different scenarios. In the first, a kashida is placed next to a sun letter to conceal the confidential bits \"00.\" The second scenario covers the sensitive bits \"11\" by inserting two kashidas after a sun letter.