For those who need an encryption tool for sending secret messages, this is for them. First BitCrypt is free and second is powerful. Based on three "filters", it can encrypt the message in bitmap images. You just have to load a bitmap into the application and the text to be encrypted. Then just choose hash algorithm for creating the cipher encryption key, choose the cipher algorithm for the encryption and the mode of cipher algorithm. The text will be hidden in the content of the image.

The encryption can be done only on bitmap images with 8 or 24 bits per pixel. If you want to encrypt larger documents try to use images with 24 bits per pixel because with 8 bits the encryption will not be perfect. You will get different visible distortions of the image.

The text should be one third of the number of the pixels present within the image. For example a solid page of text would fit into 120 by 120 pixels image.

Only using the same "filters" you can decode the message.

Pay attention because in some countries the usage of this application may be illegal.

Pluses:
Because of the strong algorithms implemented, you will not see any visual modifications to the result image; free.