# A Finite State Machine-Based Improved Cryptographic Technique
## 2 Literature Survey  
Steganography [9] entails encrypting secret information inside a seemingly benign picture. Heavy embedding, on the other hand, drastically alters the cover picture, which flags the presence of embedded data. Thus, steganography is typically insufficient for securing massive volumes of disguised data. Data security may be improved by combining encryption with other methods, such as steganography. Encryption relies on a mathematical function to encrypt data, making it unreadable by anyone except the intended recipient. The data is encrypted, but it may be snooped on if it is transferred through a wireless channel. When combined with encryption, steganography is one of the most effective techniques to conceal sensitive data [10]. To be effective, software must be able to restore both the secret information and the cover media without tampering with them.  
Reversible Data Hiding (RDH) may be used to decode and decrypt both the cover picture and the secret data since it is a lossless embedding mechanism. Researchers are now focusing on RDH in encrypted domains, also known as RDH in Encrypted Domain (RDH-ED). In the RDH-ED framework, there are two categories, separable and non-separable, which reflect whether the hidden information can be recovered. Independent RDH-ED allows for data decryption without disclosing any sensitive keys. Nevertheless, in the case of non-separable RDH-ED, the cover picture must be decrypted before the hidden data can be accessed. [PERSON] initially presented the non-separable RDH-ED cypher based on the original cover art's Advanced Encryption Standard (RDH) [11] encryption.  
Before decrypting the encrypted image and analyzing its local standard deviation for the hidden image, we first mark it. Obtaining the secret information is impossible without first decoding the cover art, making this technique inseparable from the cover art itself. This technique is simple to develop; however, it has a low embedding capacity of only 0.0625 bpp (bits per pixel).  
[PERSON] proposes a another RDH-ED approach in [12] that includes encrypting the original cover picture using an exclusive-or (XOR) operation. By carefully examining each individual component, we were able to put together the whole image. A line was drawn through the middle of each cube to separate the spaces. To conceal the information, we need to switch the three Least Significant Bits (LSB) of each pixel in a particular section of the block. This technique may simultaneously reveal the cover art and the secret data to the recipient. If the block size is off, extracting data or restoring images will fail. Using a new estimate equation and side-matching algorithm, we enhance embedding capacity and drastically reduce the error rate between neighboring blocks in approach [13]. Because data recovery requires decryption of the picture, this technique is a non-separable RDH-ED, developing differentiated histograms of data and adjusting preexisting ones [14].  
The security and dependability of a system are compromised when error-correcting codes are used with other security mechanisms. The necessity to enhance the current ME technique [15] with multi-bit error correction and a larger embedding capacity and reversibility inspired the proposed study.  
Further secret information may be added to a steganographic [16] picture by giving it the illusion of encryption. The cover image may be reversed if you reveal the hidden words on the FSM's map of its whereabouts. The cover image's components have new homes after being embedded, and the map showing where they will be kept is called the location map. At the receiver, a position map may be extracted from the codewords to reconstruct the parts of the cover picture that were untouched by the changes made during embedding. Integrating ME with FSM, which employs a cryptographic FSM, would allow for the embedding of secret data and a cover picture with improved quality, security, and reliability.