You must accept my digital signature for this applet to run. This gives it permission to access files your your computer. This is only used to load and save images, but, for security reasons, this requires user permission. If you are worried an applet will do something like erase your hard drive, DO NOT accept the digital signature.
I have since learned that hiding messages (as opposed to, or as well as, encrypting them) is known as Steganography. The best-known form of this idea is writing a message with invisible ink.
This applet encrypts ASCII (plain text) messages in an images and reads encrypted messaged. The message is stored in the least significant bits of the pixels and thus is, in theory, invisible to the human eye. However, this also means the message will be lost if the image is stored in a lossy format.
The length of the message that can be encrypted in an image depends on the size of the image. If your message does not fit, try using a larger image. All images used must be at least 3 pixels in size (this allows a message of 0 characters). There is no maximum size for images, but only the top portion of large images will be displayed.
The message in an image will be lost if the image is:
- Converted to a lossy format, like JPEG
- Converted to a format supporting a limited number of colours, like GIF (usually)
- Resized, rotated, cropped, etc.
- Sharpened, colour-corrected, etc.
- Edited (almost always)
To encrypt a message:
- Load an image to hide the message in or use the default image.
- Enter a password the message (optional).
- Enter the message in the large text box.
- Save the image now containing the hidden message.
To read a message:
- Load the image containing the message.
- Enter the password, if any.
- The message should appear in the large text box.
Image with Message:
(Password is Micah 7:5)
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