PicStealth

Steganography for Windows Runtime apps!
PicStealth will help you to hide text in pictures - just like James Bond ;)

How-To hide a text in an image:

1. Open a picture (or just use the default image)
2. Enter your text
3. Click/Tap on “hide/embed”
   Your text will be hidden in the picture. This can take some time.
4. Save the picture that contains your hidden text for future work.

How-To restore your hidden text:

1. Open the picture that contains your hidden text
2. Click/Tap the “extract” button
   The text will be extracted. This can take some time.

Option: Encrypt your Text with AES 256bit

Everyone that has access to your pictures that contain hidden text will be able to use this or a simmular software in order to extract your text. You can overcome this by using AES encryption!

Make shure that you’ve checked the “encryption” checkbox and enter a password (at least 5 digits). Don’t forget your password, otherwise you will not get your text back!

Real Steganography:

Steganography is the art and science of hiding information by embedding messages within others. Steganography works by replacing bits of useless or unused data in a picture with bits of different, invisible information.

This “unused data” are the least significant bits (LSBs) in the image pixels. The LSB is the bit that when flipped from 0 to 1 or from 1 to 0, then no significant change will occur on the total value; meaning no (optical) significant change will occur to the picture.

Fake Steganography

There are other apps that claim to provide Steganography while in fact they don’t! Those apps simply create a large file, containing the picture at position 1 followed by one or more files. Such pseudo-steganography can be easily de-coded. In fact, that’s nothing more than a ZIP file (without compression) :-)

Size of Hidden Text

Assume that the image is 1000 pixels width by 800 pixels height, then we’ll have 1000 x 800 x 3 = 2.400.000 LSBs. The pixels are multiplied by 3 because each pixel has 3 elements (red, green, blue). And as each character of our message to hide can be represented by 8 bits, then that image can hide 2.400.000 / 8 = 300.000 characters!

PNG Output

The picture containing the hidden message will be saved as an PNG image. JPEG is a lossy format. The pixels and the hidden data would be significantly altered when saving as JPEG. This would result in an “disturbed” image.

Keywords:

• cryptography
• hide text in pictures
• steganography
• encryption
• decryption
• AES 256bit