From the opening screen of Invisible Secrets you can either begin the embed- ding process or configure how the program works by clicking the Options but- ton. Figure 7.1 shows the Options dialog box and some of the settings available there.
On the general tab of the Options dialog box, you can set the action that occurs when you encrypt information and determine how the Invisible Secrets wizard or shell is displayed to the user.
One of the most critical settings here is for the shredder feature. Remember that if you use stego and someone can obtain a copy of both the original mes- sage and the message that has data hidden in it, he or she can do a comparison. When that person does, he or she is likely to notice that, though the files may look the same, they are composed of different bits. Therefore, it is critical to make sure the original message is destroyed using the shredder feature.
The other tabs in the Options dialog box contain settings that enable you to customize the application or enhance it by adding algorithms. These features aren’t present in the other tools you explored in Chapter 6, so some are worth a closer look.
The Algorithms tab of the Invisible Secrets Options dialog box is shown in Figure 7.2. The default install of Invisible Secrets comes with a subset of encryption algorithms, but if you want to add others, or even use algorithms you create, the program can easily be customized by clicking the Add Algo- rithm button.
Figure 7.2 Algorithms options screen for Invisible Secrets.
N OT E Some algorithms can be purchased and require you to enter an activation key here to enable you to use them.
On the Carriers tab of the Options dialog box shown in Figure 7.3, you can designate in what type of files Invisible Secrets can embed data. The default file types that Invisible Secrets can use to hide data are listed; new file types can be added by clicking the Add Carrier button. As with encryption algo- rithms, additional libraries of stego algorithms can be used to enhance the functionality of the program.
Once you’ve finished setting up options, it’s time to use the program to hide some data. When you open Invisible Secrets, from the screen that appears you click Next to display the Select Action settings shown in Figure 7.4. Here you choose what type of action you want the program to take, such as hiding and unhiding data using stego techniques. Because this is an integrated suite, you can also encrypt or decrypt files or securely delete information from a hard drive. You can select any of the first two options to hide and unhide informa- tion and to encrypt the data before you hide it and decrypt it after you unhide it. Using encryption with stego provides that extra level of protection; even if someone finds the data, he or she cannot read it.
For the purpose of this example you would choose the Encrypt and Hide File(s) in a Carrier File option. When you click Next to proceed to the next screen, the Select the Files You Want to Hide screen is displayed (see Figure 7.5). As you can see here, Invisible Secrets allows you to add files that already exist or to create a new message to hide.
N OT E The other interesting setting on this screen that you have not seen in any other program is the Fake File feature. Fake files are used to create
diversions. Some stego techniques, such as the .wav hiding technique that uses the least significant bits in a graphic file to hide data, are considered fairly weak. If somebody spots such a file, he or she is likely to be able to extract the hidden data. By creating fake files, even if someone can extract the hidden data, some of it will be real and some will be fake, making the attacker’s job that much harder. With this feature you can select how many fake files you want the program to create, as well as the size range for the files.
Figure 7.5 Here is where you select the files you want to hide.
After you select the files you want to hide and click Next, the Select a Car- rier File screen shown in Figure 7.6 appears. On this screen, you select an overt file or carrier file in which the data will be embedded, as well as the carrier type (the type of stego you want to use).
Selecting the carrier type may not be an obvious setting; you would think that the carrier type is set by the file extension. JPG means it is a JPEG file, and you would use the JPEG hiding technique. Invisible Secrets provides this fea- ture for the sneaky attacker who might want to take a JPEG file and name it as a .txt file to prevent the casual observer from picking up on the fact that stego is being used. If you change the extension type, Invisible Secrets will not be able to determine what technique to use, so you have to select a technique manually here.
N OT E If you don’t change the file extension, Invisible Secrets will automatically detect the proper carrier type.
Invisible Secrets also enables you to delete the original carrier file securely after data has been embedded in it by selecting the Wipe Original Carrier after Process option. If you want to check the file after you hide data in it, you can click the View button.
Once you select the carrier file and click Next, you then need to select the encryption options from the Encryption Settings screen shown in Figure 7.7. To make sure the information is protected with encryption, you should provide a strong password here. This password is required to extract and decrypt data. You can choose Skip Encryption/Hide Only to skip the encryption process and just hide the data, but for the highest security, this is not recommended.
When you click Next, you will see the screen in Figure 7.8, where you select the name of the new target file in which Invisible Secrets will save the hidden data. After you select the target file, a summary of the options you have selected to this point appears at the bottom of this screen.
Click the Hide button, and the hiding process begins. A screen appears to show you the progress. Once the data has been hidden you must click the Next button to proceed to the final step of the wizard. Where other stego tools would be finished at this point, with Invisible Secrets there is one more step in the Carrier Transfer wizard that involves making settings for the built-in net- work component (see Figure 7.9). Here you can review the file, email it, or transfer the file to an FTP site.
Figure 7.8 The Select Target File screen.
The email option brings up your email client, opens up a new message, and automatically attaches the file.
The FTP wizard brings up an FTP Connection screen where you can select the site to which you want to FTP the file, as shown in Figure 7.10. From the FTP Connection screen you can select an FTP site that allows anonymous access or one on which you have an account.
Once you have either sent an email or transferred an FTP file, you have suc- cessfully hidden information and transferred it across the Internet.