© 2004 Computer Academic Underground
Example: Audio Embedding
§Let’s assume an audio file had the following 8 bytes of data in it somewhere: 180, 229, 139, 172, 209, 151, 21, 104
§In binary, this would be:
§10110100-11100101-10001011-10101100-11010001-10010111-00010101-01101000
§If we wanted to hide the byte value ‘214’ (11010110), we use the least significant bit from each byte to hide our byte:
§10110101-11100101-10001010-10101101-11010000-10010111-00010101-01101000
§The changes result in the following bytes, which are so close to the originals that the difference will be inaudible:
§Modified: 181, 229, 138, 173, 208, 151, 21, 104
§Original: 180, 229, 139, 172, 209, 151, 21, 104
§
•(Go over the content of the slide)
•As you can see, only four of the eight bytes of data actually changed values.
•Obviously using this method, the cover-medium needs to be at least 8 times the size of the message in order to make embedding the entire message possible.