Question

• Images can be digitally altered to change the “facts”.
• Sometimes the process used to hide information can be undone.
• Steganography is used to hide messages inside of images.

If any image on the internet could hide secret messages, how can governments or other agencies find these message?

Some companies, like ebay, process images when uploaded to remove possible hidden messages. Should all image hosting sites be required to modify images to remove messages?

Finally, can you think of reasons we would not want possible steganography to be used? In other words, is there a good use of steganography or is it all negative?

Answer 1

If any image on the internet could hide secret messages, how can governments or other agencies find these message?

--> Government or Other agencies have different tools to findout the message behind the image. Steganography allows hiding message among the contents like images, videos, audios etc. For eg, image uploaded on internet contains some special message for someone, that person simply download the file recover the message with the password which that person already knows.
   Steganalysis is the process of detecting steganographic message. Government or agencies uses tools which uses steganalysis. It is two stage process- 1. Finding out if image is stego-bearing or not and finding the location of stego pixels, where actual message is stored.

Some companies, like ebay, process images when uploaded to remove possible hidden messages. Should all image hosting sites be required to modify images to remove messages?

--> Yes, companies like ebay uses the above process to remove the possible hidden messages. They use different filters and algorithms to find out such images.

Finally, can you think of reasons we would not want possible steganography to be used? In other words, is there a good use of steganography or is it all negative?

--> Yes there are pros and cons of Steganography.
   Pros-   1. Modern Printers   2. Use by Government Officials   3. Distributed steganography
       4. In Business, can share trends and secrets without knowing the message.
   Cons-   1. Use By Terriorists.   2. Use by Hackers.