Not sure if this is the same subject, but we embed the encryption keys for our database into the machine code of the application which accesses the database. This means that they are inaccessible to any human. When the time comes to change the keys, the application does so without informing anyone, and re-encrypts the database with the new keys.

Is that the kind of thing you're interested in? It's described in detail in here:

Article Securely Encrypting Data At Rest

Dear Prof.

Thank you for sharing this answer .

Regards

Khamis

I'm not aware of recent changes in the basic approach. In sound, encoding data into the low bits would make the differences caused by the data undetectable to human ears while providing a clear bitstream to a computer. If the data is encrypted, it will seem like noise to a detector. Various detection approaches are based on statistical analysis, but that is outside the question.

For text, it depends what exactly you mean by "text". ASCII is the most difficult. There are a couple of approaches using whitespaces, but you cannot really hide in ASCII. As soon as you go to RTF, HTML, DOC or other more "rich" texts, options open up as the same kind of non-essential content appears that can be used.

Data hiding ,what ever may be text, audio,video etc can be securely possible by the way of incorporating with the advanced beautiful concept called digital watermarking.Even the hologram concept also applical in this.you can refer my basic video lecture in YouTube.

In general, steganography hides information in redundant structures. So you have to examine a format to identify what is redundant. With text this will be the character encoding and formatting, and in some cases spelling and punctuation. With audio it will be the audio signal itself, where the resolution of the codec is greater than can be discerned by the recipient, and the way any compression is used if it has alternative encodings - simple PCM has one way of encoding, but more advanced codecs might allow the use of compression resets to be varied as a way of encoding small amounts of information.

The question as to what methods are popular is more difficult to answer. Regards Stegware (steganography used in cyber attacks) most discovered attacks are using simple image steganography, but as it is undetectable it is not clear what is actually being used. But images have the advantage that browser scripts are able to manipulate them, which is popular method right now so I would guess it is the favourite.

Discrete logarithmic Function, Advance Encryption Algorithm

SHA-1, SHA-5, message digest, Signcription, Big Numerical Factorization, ECC, and other procedures are used for securing data from unauthorized user

You can read my recent article

I met with cases of hiding information by deleting files that the recipient was to recover, rename files and hide them eg in the operating system directory. Try to guess which files with names similar to hixy8.dll, after changing the extension to jpg will be a photo ...

I have also seen catalogs that contain prohibited signs in their names (eg * or?) - it's easy to guess that someone wanted to hide something.

The information can also be hidden in areas outside LBA addressing - HPA and DCO as well as in the Service Area.

http://t13.org/Standards/Default.aspx?DocumentType=3&DocumentStage=2

I also met the information on the inside of the hard disk cover with a felt pen. When looking for hidden information, you must take into account that human ingenuity knows no boundaries, and the information transmitted does not have to be in digital form.

Thank you for answer. - Khamis

The most popular is LSB (Least Significant Bit) with encryption. There are several LSB methods using LSBs of bytes choosen by the key.

To secrete your sound file,you can hide QR code and text inside audio or sound file ,so that it will be more secure for communication

Olga says "LSB is most popular". Probably true, but worth exploring how you measure "popular".

Is it the number of attacks that use the technique, the number of tools people publish that use the technique or the number of times an attack succeeds by using the technique?

Attackers are certainly using techniques where the information is in the pixel, as this is available to Javascript through the DOM. So easy to write JS that decodes steg from an image loaded into the same web page. Hence its popularity in malvertising.

But with JPEG LSB you are modifying DCT coefficients and there are even more stealthy ways of encoding available with this, but these are not accessible to JS, because it only sees the pixel values derived from the DCT and not the DCT itself. So much more stealthy, but not so easy to exploit = probably less used.

But if attackers are using stealthy DCT encodings, they are less likely to be detected, as the steg can be invisible. So how do we know if they're being used? How do you judge how popular an attack technique is when it is undetectable? - I don't think we can ask the bad guys.

We could ask "what's easiest to exploit" by a remote attack - that'll be LSB in lossless compression. But "what's best to exploit" once an attack is in place is probably something much more stealthy that requires real code to run, such as F5 in JPEG.

Dear Sir;

thank you very much for answer

Regards

Khamis

For the text, these are semantic and syntactic methods.

For sound, this is phase encoding, encoding echo signals, etc. The properties of the human hearing system are used. For example, people do not hear a change in the initial phase. People do not hear a change in the echo of the signal. These are redundant data, they can be replaced by information messages.

The methods of LSB are very primitive. It's easy to detect and delete the message.

Text Steganogrphy

Article Text Steganography Using Compression and Random Number Generators

I support this opinion, and even more, I can say this area of science has enough chances to became great and strong science and to give to any researches well perspectives to obtain excellent results.