Computers Talk Binary
http://www.roubaixinteractive.com/PlayGrou
nd/Binary_Conversion/Binary_to_Text.asp
• Send me a polite or
write me a polite
coded binary
message
• dpruitt@umd.edu
• http://www.roubaixinte
ractive.com/PlayGrou
nd/Binary_Conversion
/Binary_to_Text.asp
Even Pictures are Binary
Steganography
http://www.wired.com/wired/archive/7.07/what.html
Steganography
• Means covered writing
• dates back to ancient Greece
– common practices
– etching messages in wooden tablets and
covering them with wax
– tattooing a shaved messenger's head, letting
his hair grow back, then shaving it again when
he arrived at his contact point
Other codes
• Breaking the code
carved into the
ceiling of the
Rosslyn Chapel
in Scotland reveals
a series of
musical passages.
http://science.howstuffworks.com/code-breaker.htm/printable
“invisible writing”
• Another common form of Steganography is through the
use of Invisible inks.
• Such inks were used with much success as recently as
WWII.
• An innocent letter may contain a very different message
written between the lines
• Can you see me
• Early in WWII steganographic technology consisted
almost exclusively of invisible inks [Kahn67]. Common
sources for invisible inks are milk, vinegar, fruit juices
and urine. All of these darken when heated.
Steganography
• Art and science of disguising or hiding
information in the form of something else
– embedding messages within other text
– images or information may be encoded into
pictures or texts files
• The “invisible” files can be (compiled and)
retrieved by those with code
Embedding Messages Within Other Text
Null ciphers (unencrypted messages). The real message is "camouflaged" in
an innocent sounding message.
• Fishing freshwater
bends and saltwater
coasts rewards
anyone feeling
stressed. Resourceful
anglers usually find
masterful leapers fun
and admit swordfish
rank overwhelming
anyday.
• By taking the third
letter in each word,
the following
message emerges
• Send Lawyers, Guns,
and Money.
Source:
http://www.jjtc.com/stegdoc/sec202.html
The following message was actually
sent by a German Spy in WWII
• Apparently neutral's
protest is thoroughly
discounted and
ignored. Isman hard
hit. Blockade issue
affects pretext for
embargo on by
products, ejecting
suets and vegetable
oils.
• Taking the second
letter in each word the
following message
emerges:
• Pershing sails from
NY June 1
Source: http://www.jjtc.com/stegdoc/sec202.html
Word-Shifting
By overlapping the two messages
you get:
We explore new steganographic
and cryptographic algorithms and
techniques throughout the world to
produce wide variety and security in
the electronic web called the
Internet.
Expand the space before explore,
the, wide, and web by one point
and condensing the space after
explore, world, wide and web by
one point in sentence S1.
Embedding Text in Pictures
Embedding Messages within
photos
• The larger the given message is relative to the hidden message, the
easier it is to hide it
• For this reason, digital pictures (which contain large amounts of
data) are used to hide messages on the Internet and on other
communication media.
• a 24-bit bitmap will have 8 bits representing each of the three color
values (red, green, and blue) at each pixel.
• If we consider just the blue there will be 28 different values of blue.
• The difference between 11111111 and 11111110 in the value for
blue intensity is likely to be undetectable by the human eye.
• Therefore, the least significant bit can be used (more or less
undetectably) for something else other than color information. If we
do it with the green and the red as well we can get one letter of
ASCII text for every three pixels.
Can you tell the difference?
With your parents help
SOURCE: http://mozaiq.org/encrypt/ AND http://mozaiq.org/decrypt/