What is Cyber Forensics ? (Part 16)

What is Cyber Forensics ? (Part 16)
Steganography
ဓတ္ပုံအတြင္း Secret ထည့္သြင္းျခင္း
jPEG,JPG,PNG,BMP စတဲ့ ဓတ္ပုံေတြမွာ မိမိ၀ွက္ခ်င္တဲ့ စာသားကုိ ထည့္ျပီး အမ်ားမသိေအာင္ ၀ွက္ထားျခင္းပါ ... ၀ွက္တဲ့နည္းစနစ္ကေတာ့
ဓတ္ပုံရဲ႕ Pixel နဲ့ Resolution အေနအထားကုိလုိက္ျပီး bit ေတြကုိ တစ္ေနရာျခင္းစီအလုိက္အစားထုိးတာပါ ...တစ္ေနရာျခင္းစီ အလုိက္ အစားထုိးလုိက္တဲ့အတြက္ အမ်ားအျမင္မွာ မသိသာေတာ့ပါဘူး ...
Eg..... ပုံရဲ့ bit stream က ေအာက္ပါအတုိင္းဆုိပါစုိ႕ ..
.
(10111110) (10111111) (10111111) (10111111) (10111111) (10111111) (10111111) (10111110)
အဲအထဲမွာ A ဆုိတာထည့္၀ွက္မယ္ ဆုိရင္ .... A ရဲ့ binary က 10000001
ျဖစ္ပါတယ္။ ထည့္၀ွက္တဲ့ ျပီးတဲ့ အခ်ိန္မွာ ပုံရဲ့ bit stream က ေအာက္ပါအတုိင္း ေျပာင္းလဲသြားပါမယ္ ....ေနာက္ဆုံးအလုံးေတြကုိ ၾကည့္ၾကည့္ပါ..
(10111111) (10111110) (10111110) (10111110) (10111110) (10111110) (10111110) (10111111)
အထက္ပါနည္းကုိ Least bit Intersection (LSB) လုိ႕ေခၚပါတယ္။
mp3 ဖုိင္းမ်ားအတြင္းထည့္သြင္းျခင္း
mp3 .wav ဖုိင္းမ်ားအတြင္း မိမိ၀ွက္ခ်င္တဲ့ စာသား သုိ႕မဟုတ္ စကား ကုိ ထည့္ျပီး အမ်ားမသိေအာင္ ၀ွက္ထားျခင္းပါ ...၀ွက္တဲ့နည္းစနစ္ကေတာ့
အထက္မွာ ေဖာ္ျပထားတဲ့
Least bit Intersection (LSB) နည္းစနစ္
Frequency (DSSS-Direct Sequence Spread Spectrum)
(FHSS-Frequency Hopping Spread Spectrum)
(ECHO) နည္းစနစ္တို႕ျဖစ္ပါတယ္ .. ။
Least bit Intersection (LSB) စနစ္ကုိေတာ့ အထက္မွာေဖာ္ျပထားျပီးျဖစ္ပါတယ္ ..

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