All computer based pictures are composed of an array of dots, called pixels, that make up a very fine grid. Each one of these pixels has its own colour, represented internally as separate quantities of red, green and blue.
Within Windows, each of these colour levels may range between 0 none of the colour and a full amount of the colour. A pixel with an RGB value of 0 0 0 is black, and one with a value of is white. For a 24 bit image this is simple because 24 bit images are stored internally as RGB triples, and all we need to do is spread our bits and save out the new file. The drawback to this is that 24 bit images are uncommon, and would therefore attract the attention of those whose attention you are trying to avoid attracting!
It is considerably more difficult to hide anything within a colour image. This is because the image may already have over colours which our meddling will carry to way over the absolute maximum of Looking at a little theory it is easy to see that an image with 32 or less colours will never exceed colours, no matter how much we meddle with it.
As we pass through it in our hiding process we can change it to any one of 8 possible values, the binary digits from to , one of which is the original pattern. There is no guarantee that 32 colours is our upper limit for every file that you want to hide though.
If you're lucky the file will not change a colour to all of its 8 possible combinations and then we are able to keep one more of the original colours. In practice, however, you will often find pictures being reduced to the minimum of 32 colours. S-Tools tries to reduce the number of image colours in a manner that preserves as much of the image detail as possible.
It usually makes a very good job too, I can often not tell the difference between a colour scanned image and one reduced to The caveat is speed. Didn't think so. S-Tools prepends some extra information on to the front of the raw file data before hiding. This apparently meaningless step means that two identical hidden files that are encrypted in CBC or PCBC mode will never encipher to the same ciphertext.
In order to further conceal the presence of a file, S-Tools picks its bits from the image based on the output of a random number generator. This is designed to defeat an attacker who might apply a statistical randomness test to the lower bits of the image to determine whether encrypted data is hidden there well-encrypted data shows up as pure white noise.
S-Tools allows you to hide files in the unused space on floppy disks. But what exactly do we mean by "unused space". Let's take a little look at the way that DOS organises the files on a disk. Every floppy disk, when formatted, is divided into what are called sectors. Each sector on a disk can hold usually bytes of information. So, on a 1. When you write a file on to disk, DOS computes how many sectors it will need to hold the file and writes this information into a special area at the start of the disk known as the file allocation table FAT.
S-Tools does not hide information in consecutive sectors on disk, as this would be too easy. Instead it uses a cryptographically strong random number generator to choose which of the free sectors it should use. To further add to the security it also allows you to fill all other unused sectors on the disk with random rubbish to confuse an attacker even more.
S-Tools is shareware. That means that if you find it useful and would like to continue to use it after a reasonable trial period, which I consider to be about one calendar month, then you should register your copy of the program with Andy Brown. Please do take the time to read the help files, there are some useful hints amongst the rather dry command descriptions that you may benefit from.
If you decide to encrypt your files then don't feel safe just because the algorithm used is immune to attack. An enemy will attack the weakest link in the chain; and that is you.
Use "good" passphrases that don't appear in any books or literature. A nonsense phrase that's a combination of two or more meaningful phrases is one such possibility. Oh yeah, don't go leaving the file that you've just hidden sitting around on your hard disk. I am also contactable via e-mail at a. I encourage and prefer PGP encrypted mail, and you can get my public keys by fingering asb vulcan. If you're wondering why the host name must be specified as well as the domain, it's because the gateway host at NEXOR resolves finger queries through the X.
There is also a portable version available which, you can run with the help of a USB and there is no need to install the product. Advanced users can enjoy the impressive command line interface. Do keep in mind that you have maple hard drive space, as images normally occupy a lot of space.
For additional space, you can manage four different virtual drives through Lite version free installation. On the other hand the professional or the paid version allows users to create 32 drives at the same time.
With the help of this software now, there is no need to swap CDs and wait for them to play. All those, who are interested, must note that Daemon Tools Lite does not mount every other image format out there. But there are several formats out there that are supported easily and there are no bugs. After installing the program, you can make use of different add-ins, like one for creating ISO images, and for handling the Securom based copy protected discs. This program has a complete plug-in architecture.
Daemon Tools Lite is good for those, who spend swapping and mounting different CDs. Professional users are recommended to install the paid version for optimum options and results. Leave a Reply Cancel reply You must be logged in to post a comment. This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.
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