# A Dynamic Multi-Layer Steganography Approach Based on Arabic Letters' Diacritics and Image Layers
## 3 The Proposed Approach
The second scenario relies on the disjunctive Hamza () and conjunctive Hamza (). As many native speakers of the Arabic language make mistakes in writing some words that contain Hamza, the idea is similar to the first scenario. We will replace the disjunctive Hamza () with () with a Alif with Kasrah () in the case of 1, or it will remain the same in the case of 0. The same method will be used on the upper Hamza also, changing () into (), which is difficult even to notice by eye when reading the text, which is the most important goal of the science of concealment. We note that in this model, the pattern is relied upon, and therefore there is no need for a table or map to be agreed upon between the sender and the receiver, but this leads to an increase in the number of characters in the new text compared to the old text, and as well as a lower level of security compared to the first scenario. It is worth noting that a map can be employed in the second scenario and a pattern in the first scenario. It is worth mentioning that in this scenario, a specific model was relied upon in the concealment process, and therefore there is no need for a table or map to be agreed upon between the sender and the receiver. However, using this scenario, the size of the new text will be larger than the old text because of the introduction of new characters. Additionally, the level of safety will be lower than the previous scenario. The map can be reused in the second scenario and the model can be reused in the first scenario. Algorithms 1 and 2 depict the proposed scenarios (first and second Scenarios). For a deeper understanding of the above two scenarios, Figures 10 and 11 show an example of a practical implementation of the application we developed to ensure the effectiveness and achievability of the proposed approach. Figure 9: Examples of Hamza in the Arabic language. Assuming we have the following Arabic text as a cover for what we want to hide:  
In the beginning, the application calculates the statistics of the cover text in order to know the threshold of embedding (in our case, the text contains eight diacritics and four Hamzas), meaning that the maximum number of bits that we can hide is 12 bits in this phrase, which is illustrated in Figures 10 and 11. Assuming that the message to be hidden is 011 (this is the output of Phase 1), in the first proposed scenario, which involves concealing through diacritics, first we entered the table agreed upon between the two parties (concealing positions), which is provided in the example shown in Figure 10 (1#3#7). This means that the concealing will be performed in the first, the third, and the seventh diacritics. Note that the diacritic that corresponds to the number 0 is replaced by the Fatha, and the diacritic that corresponds to the number 1 is replaced by the Dammah. Therefore, we did not change the vowel in the word \"\(\backslash\)\(\backslash\)\(\backslash\)\(\backslash\)\", but we changed it to a Dammah in the word \"\(\backslash\)\(\backslash\)\(\backslash\)\(\backslash\)\" and the word \"\(\backslash\)  
There is a condition that is tested before implementation, which is that the number of positions in the map agreed upon must be identical to the length of the message, and the last position in the map is smaller than the total number of diacritics in the text. Similarly, in the second proposed scenario (where no hiding map is needed), the Hamza corresponding to 0 is swapped from the beginning, which is an upper Hamza \"!\", with \"(Alif with Fatha), while the lower Hamza \"!\" is replaced by \"!\" (Alif with Kasrah), which is difficult to spot with the naked eye. We note in Figure 11 that only the Hamza in the word \"\(\blacktriangle\)\" was replaced by an Alif with Fatha and became \"\(\blacktriangle\)\". In addition, in order to increase the amount of data that can be concealed and the level of security, the two proposed scenarios can be combined.