50min talk for a Cryptography course I did during 2010/2011 year.

1. Steganography
Hiding information in past, present and future.
Alberto Villegas Erce
albvi@correo.ugr.es
Cryptography
University of Granada
April 2010
Alberto V. E. (CRYP - UGR) Steganography April 2010 1 / 38

2. Review
Concepts review
Previously in crypto-world...
Math background
Modular arithmetics give us the power
Factorization and Primality.
Finite fields.
Pseudo-random Sequences.
...
Cryptography History
From ancient greeks to Enigma machine.
Information Theory
Shannon’s theory for perfect crypto security.
Alberto V. E. (CRYP - UGR) Steganography April 2010 2 / 38

3. Review
Today
Steganography
What is Steganography?
We will review the topic through history
1 Past: historical examples.
2 Present: digital era.
3 Future: no-that-much science fiction
ideas.
Alberto V. E. (CRYP - UGR) Steganography April 2010 3 / 38

4. Review
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 4 / 38

5. Introduction
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 5 / 38

6. Introduction
Stegano... what?
What is Steganography?
A word with 4 vowels...
... and 9 consonants.
Sounds like Cryptography.
Error!
You are doing it wrong!
Greek: “concealed writing”
Steganos: covered or protected.
Graphein: to write.
Alberto V. E. (CRYP - UGR) Steganography April 2010 6 / 38

7. Introduction
Stegano... what?
What is Steganography?
A word with 4 vowels...
... and 9 consonants.
Sounds like Cryptography.
Error!
You are doing it wrong!
Greek: “concealed writing”
Steganos: covered or protected.
Graphein: to write.
Alberto V. E. (CRYP - UGR) Steganography April 2010 6 / 38

8. Introduction
Stegano... what?
What is Steganography?
A word with 4 vowels...
... and 9 consonants.
Sounds like Cryptography.
Error!
You are doing it wrong!
Greek: “concealed writing”
Steganos: covered or protected.
Graphein: to write.
Alberto V. E. (CRYP - UGR) Steganography April 2010 6 / 38

9. Introduction
Stegano... what?
What is Steganography?
A word with 4 vowels...
... and 9 consonants.
Sounds like Cryptography.
Error!
You are doing it wrong!
Greek: “concealed writing”
Steganos: covered or protected.
Graphein: to write.
Alberto V. E. (CRYP - UGR) Steganography April 2010 6 / 38

10. Introduction
Stegano... what?
What is Steganography?
A word with 4 vowels...
... and 9 consonants.
Sounds like Cryptography.
Error!
You are doing it wrong!
Greek: “concealed writing”
Steganos: covered or protected.
Graphein: to write.
Alberto V. E. (CRYP - UGR) Steganography April 2010 6 / 38

11. Introduction
Steganography
Definition
Steganography
Art and science of writing hidden messages in such a way that no one
suspects the existence of the message.
But, then, what is the difference with
Cryptography?
“Cryptography is about protecting the
content of messages, steganography is
about concealing their very existence” [1]
Alberto V. E. (CRYP - UGR) Steganography April 2010 7 / 38

12. Introduction
Steganography
Definition
Steganography
Art and science of writing hidden messages in such a way that no one
suspects the existence of the message.
But, then, what is the difference with
Cryptography?
“Cryptography is about protecting the
content of messages, steganography is
about concealing their very existence” [1]
Alberto V. E. (CRYP - UGR) Steganography April 2010 7 / 38

13. Introduction
Steganography
Terminology [1]
Embedded data (M): the message that one wishes to send secretly.
Cover-text (O): (covert-image or cover-audio) innocuous message
used to hide the embedded data.
Stego-key (K ): used to control the hiding process.
˜
Stego-object (M): the combination of the previous.
˜
M ×O ×K →M
Alberto V. E. (CRYP - UGR) Steganography April 2010 8 / 38

14. Introduction
Steganography
Terminology [1]
Embedded data (M): the message that one wishes to send secretly.
Cover-text (O): (covert-image or cover-audio) innocuous message
used to hide the embedded data.
Stego-key (K ): used to control the hiding process.
˜
Stego-object (M): the combination of the previous.
˜
M ×O ×K →M
Alberto V. E. (CRYP - UGR) Steganography April 2010 8 / 38

15. Introduction
Steganography
Terminology [1]
Embedded data (M): the message that one wishes to send secretly.
Cover-text (O): (covert-image or cover-audio) innocuous message
used to hide the embedded data.
Stego-key (K ): used to control the hiding process.
˜
Stego-object (M): the combination of the previous.
˜
M ×O ×K →M
Alberto V. E. (CRYP - UGR) Steganography April 2010 8 / 38

16. Introduction
Steganography
Terminology [1]
Embedded data (M): the message that one wishes to send secretly.
Cover-text (O): (covert-image or cover-audio) innocuous message
used to hide the embedded data.
Stego-key (K ): used to control the hiding process.
˜
Stego-object (M): the combination of the previous.
˜
M ×O ×K →M
Alberto V. E. (CRYP - UGR) Steganography April 2010 8 / 38

17. Introduction
Steganography
Terminology [1]
Embedded data (M): the message that one wishes to send secretly.
Cover-text (O): (covert-image or cover-audio) innocuous message
used to hide the embedded data.
Stego-key (K ): used to control the hiding process.
˜
Stego-object (M): the combination of the previous.
˜
M ×O ×K →M
Alberto V. E. (CRYP - UGR) Steganography April 2010 8 / 38

18. Introduction
Steganography
Model (I)
Figure: Steganography abstract process
Alberto V. E. (CRYP - UGR) Steganography April 2010 9 / 38

19. Introduction
Steganography
Model (II)
Pure versus secret key steganography
Pure steganographic systems:
no prior exchange of secret information.
Secret key steganography system:
embeds secret using a secret key.
Perfect Secure Stego-system
It exists. Apply the concepts we saw two
weeks ago.
Alberto V. E. (CRYP - UGR) Steganography April 2010 10 / 38

20. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

21. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

22. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

23. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

24. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

25. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

26. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

27. Introduction
Steganography
Who is it for?
Who is using steganography
nowadays?
Spies: intelligence and
counterintelligence agences.
Militaries: unobtrusive
communications.
Terrorists: “it arouses less
suspicion” - John Wilkins (1641)
Copyright: watermarks and
fingerprints.
SPAM: email forgery.
Only the good guys!
(actually, is not that bad)
Alberto V. E. (CRYP - UGR) Steganography April 2010 11 / 38

28. Introduction
Steganography
Examples?
Stop!
Could someone give an example of Steganography right now?
My recommendation
Think before going deeper
into a topic.
Think about what happened
so far.
Alberto V. E. (CRYP - UGR) Steganography April 2010 12 / 38

29. Introduction
Steganography
Examples?
Stop!
Could someone give an example of Steganography right now?
My recommendation
Think before going deeper
into a topic.
Think about what happened
so far.
Alberto V. E. (CRYP - UGR) Steganography April 2010 12 / 38

30. Introduction
Steganography
Examples?
Stop!
Could someone give an example of Steganography right now?
My recommendation
Think before going deeper
into a topic.
Think about what happened
so far.
Alberto V. E. (CRYP - UGR) Steganography April 2010 12 / 38

31. Past
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 13 / 38

32. Past
China
Silk passion
Paper masks: The sender and the receiver shared copies of a paper
mask with a number of holes cut at random locations (keep this in
mind).
Wax balls: The also wrote messages on silk and encased them in balls
of wax. The wax ball could then be hidden in the messenger.
Alberto V. E. (CRYP - UGR) Steganography April 2010 14 / 38

33. Past
Greece
#HerodotusFacts
Shaved slaves: messages
were written over slaves
heads. Still in 20th
century!
Wax tablet: a good
example of camouflage
over unsuspicious diary
objects.
Alberto V. E. (CRYP - UGR) Steganography April 2010 15 / 38

34. Past
Music
Stego-heros
Gaspar Schott (17th
century): music notes
coding letters.
John Wilkings (17th
century): talking
musicians.
J. S. Bach (17th-18th century):
embedded his name in the organ
chorale “Vor deinen Thron”
using the rule: if the i-th note of
the scale occurs k times, then
the k-th letter of the alphabet is
to be entered in the i-th place.
Alberto V. E. (CRYP - UGR) Steganography April 2010 16 / 38

35. Past
Writing
Acrostic, morse and more.
A boat, beneath a sunny sky
Lingering onward dreamily
In an evening of July -
Children three that nestle near,
Eager eye and willing ear,
Pleased a simple tale to hear -
Long has paled that sunny sky:
Acrostic: messages hidden in
Echoes fade and memories die: text using patterns.
Autumn frosts have slain July.
Still she haunts me, phantomwise, Morse Code with {i, j, f, t}:
Alice moving under skies another good example of
Never seen by waking eyes.
Children yet, the tale to hear,
camouflage over unsuspicious
Eager eye and willing ear, diary objects.
Lovingly shall nestle near.
In a Wonderland they lie,
Dreaming as the days go by, Is Father Dead or Deceased?
Dreaming as the summers die:
Ever drifting down the stream -
Lingering in the golden gleam -
Life, what is it but a dream?
Alberto V. E. (CRYP - UGR) Steganography April 2010 17 / 38

36. Past
Writing
Acrostic, morse and more.
A boat, beneath a sunny sky
Lingering onward dreamily
In an evening of July -
Children three that nestle near,
Eager eye and willing ear,
Pleased a simple tale to hear -
Long has paled that sunny sky:
Acrostic: messages hidden in
Echoes fade and memories die: text using patterns.
Autumn frosts have slain July.
Still she haunts me, phantomwise, Morse Code with {i, j, f, t}:
Alice moving under skies another good example of
Never seen by waking eyes.
Children yet, the tale to hear,
camouflage over unsuspicious
Eager eye and willing ear, diary objects.
Lovingly shall nestle near.
In a Wonderland they lie,
Dreaming as the days go by, Is Father Dead or Deceased?
Dreaming as the summers die:
Ever drifting down the stream -
Lingering in the golden gleam -
Life, what is it but a dream?
Alberto V. E. (CRYP - UGR) Steganography April 2010 17 / 38

37. Past
Writing
Acrostic, morse and more.
A boat, beneath a sunny sky
Lingering onward dreamily
In an evening of July -
Children three that nestle near,
Eager eye and willing ear,
Pleased a simple tale to hear -
Long has paled that sunny sky:
Acrostic: messages hidden in
Echoes fade and memories die: text using patterns.
Autumn frosts have slain July.
Still she haunts me, phantomwise, Morse Code with {i, j, f, t}:
Alice moving under skies another good example of
Never seen by waking eyes.
Children yet, the tale to hear,
camouflage over unsuspicious
Eager eye and willing ear, diary objects.
Lovingly shall nestle near.
In a Wonderland they lie,
Dreaming as the days go by, Is Father Dead or Deceased?
Dreaming as the summers die:
Ever drifting down the stream -
Lingering in the golden gleam -
Life, what is it but a dream?
Alberto V. E. (CRYP - UGR) Steganography April 2010 17 / 38

38. Past
Writing
Acrostic, morse and more.
A boat, beneath a sunny sky
Lingering onward dreamily
In an evening of July -
Children three that nestle near,
Eager eye and willing ear,
Pleased a simple tale to hear -
Long has paled that sunny sky:
Acrostic: messages hidden in
Echoes fade and memories die: text using patterns.
Autumn frosts have slain July.
Still she haunts me, phantomwise, Morse Code with {i, j, f, t}:
Alice moving under skies another good example of
Never seen by waking eyes.
Children yet, the tale to hear,
camouflage over unsuspicious
Eager eye and willing ear, diary objects.
Lovingly shall nestle near.
In a Wonderland they lie,
Dreaming as the days go by, Is Father Dead or Deceased?
Dreaming as the summers die:
Ever drifting down the stream -
Lingering in the golden gleam -
Life, what is it but a dream?
Alberto V. E. (CRYP - UGR) Steganography April 2010 17 / 38

39. Past
Writing
Acrostic, morse and more.
A boat, beneath a sunny sky
Lingering onward dreamily
In an evening of July -
Children three that nestle near,
Eager eye and willing ear,
Pleased a simple tale to hear -
Long has paled that sunny sky:
Acrostic: messages hidden in
Echoes fade and memories die: text using patterns.
Autumn frosts have slain July.
Still she haunts me, phantomwise, Morse Code with {i, j, f, t}:
Alice moving under skies another good example of
Never seen by waking eyes.
Children yet, the tale to hear,
camouflage over unsuspicious
Eager eye and willing ear, diary objects.
Lovingly shall nestle near.
In a Wonderland they lie,
Dreaming as the days go by, Is Father Dead or Deceased?
Dreaming as the summers die:
Ever drifting down the stream -
Lingering in the golden gleam -
Life, what is it but a dream?
Alberto V. E. (CRYP - UGR) Steganography April 2010 17 / 38

40. Past
Invisible Ink
Lemon, urine: after burned
released carbon shows up.
Refined with chemistry: salt
ammoniac dissolved in water.
Refined with biology: some
natural unique responses.
Wait a second...
Alberto V. E. (CRYP - UGR) Steganography April 2010 18 / 38

41. Past
Invisible Ink
Lemon, urine: after burned
released carbon shows up.
Refined with chemistry: salt
ammoniac dissolved in water.
Refined with biology: some
natural unique responses.
Wait a second...
Alberto V. E. (CRYP - UGR) Steganography April 2010 18 / 38

42. Past
Publishing
Not only for war
Steganography has protected copyright even when it did not exists.
Intended gaps: False
intended data.
Microdots: imperceptible
dots.
Line spacing: modern
publishing.
Alberto V. E. (CRYP - UGR) Steganography April 2010 19 / 38

43. Present
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 20 / 38

44. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

45. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

46. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

47. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

48. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

49. Present
Digital Era
Follow the white rabbit
Digital era: how do we
manage data now?
Sound: bit streams.
Images: bit streams.
Video: bit streams.
Text: bit streams.
Noise
A weak spot to exploit.
Alberto V. E. (CRYP - UGR) Steganography April 2010 21 / 38

50. Present
A simple idea
Take a closer look
Alberto V. E. (CRYP - UGR) Steganography April 2010 22 / 38

51. Present
A simple idea
A said CLOSER!
(a) #18657E (b) #19657E (c) #1A657E (d) #1B657E
Figure: LSB variations over R
Alberto V. E. (CRYP - UGR) Steganography April 2010 23 / 38

52. Present
LSB Steganography
I have discovered a truly marvelous proof of this, which this pixel is too narrow to contain.
LSB Steganography
LSB Variations are indiscernible.
Even the two LSB!
Let’s check a poor 800 × 600 image.
(a) #18667D
800 × 600 = 48000pixels
480000pixels × 6 = 2880000bit
2880000bit
= 360000characters
8bit/character
(b) #1B657E
Alberto V. E. (CRYP - UGR) Steganography April 2010 24 / 38

53. Present
LSB Steganography
I have discovered a truly marvelous proof of this, which this pixel is too narrow to contain.
LSB Steganography
LSB Variations are indiscernible.
Even the two LSB!
Let’s check a poor 800 × 600 image.
(c) #18667D
800 × 600 = 48000pixels
480000pixels × 6 = 2880000bit
2880000bit
= 360000characters
8bit/character
(d) #1B657E
Alberto V. E. (CRYP - UGR) Steganography April 2010 24 / 38

54. Present
LSB Steganography
I have discovered a truly marvelous proof of this, which this pixel is too narrow to contain.
LSB Steganography
LSB Variations are indiscernible.
Even the two LSB!
Let’s check a poor 800 × 600 image.
(e) #18667D
800 × 600 = 48000pixels
480000pixels × 6 = 2880000bit
2880000bit
= 360000characters
8bit/character
(f) #1B657E
Alberto V. E. (CRYP - UGR) Steganography April 2010 24 / 38

55. Present
LSB Steganography
I have discovered a truly marvelous proof of this, which this pixel is too narrow to contain.
LSB Steganography
LSB Variations are indiscernible.
Even the two LSB!
Let’s check a poor 800 × 600 image.
(g) #18667D
800 × 600 = 48000pixels
480000pixels × 6 = 2880000bit
2880000bit
= 360000characters
8bit/character
(h) #1B657E
Alberto V. E. (CRYP - UGR) Steganography April 2010 24 / 38

56. Present
LSB Steganography
Pros Cons
Easy to understand and code. Weak against noise attack.
Pure steganographic (a priori). Requires good images.
Lot’s of coding chances. [3] Requires non-coded images.
Alberto V. E. (CRYP - UGR) Steganography April 2010 25 / 38

57. Present
Wattermarking
Copyrigthing
Problem
Lossy compression (JPEG,
MGEP) destroys LSB variations.
Solution
Hide in other LSB.
Also indiscernible for human eye.
Alberto V. E. (CRYP - UGR) Steganography April 2010 26 / 38

58. Present
Wattermarking
Copyrigthing
Concepts
Visible watermarking.
Invisible watermarking.
Requires redundancy!
Also valid for video compression.
Alberto V. E. (CRYP - UGR) Steganography April 2010 27 / 38

59. Present
Wattermarking
Copyrigthing
Concepts
Visible watermarking.
Invisible watermarking.
Requires redundancy!
Also valid for video compression.
Alberto V. E. (CRYP - UGR) Steganography April 2010 27 / 38

60. Present
Wattermarking
Copyrigthing
Concepts
Visible watermarking.
Invisible watermarking.
Requires redundancy!
Also valid for video compression.
Alberto V. E. (CRYP - UGR) Steganography April 2010 27 / 38

61. Future
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 28 / 38

62. Future
Science fiction?
Keep your mind open
Where are the limits?
Science and engineering develop
fast.
Multiple fields merge and split
continuously.
What can we learn from other fields?
Keep your mind open!
Alberto V. E. (CRYP - UGR) Steganography April 2010 29 / 38

63. Future
Science fiction?
Keep your mind open
Where are the limits?
Science and engineering develop
fast.
Multiple fields merge and split
continuously.
What can we learn from other fields?
Keep your mind open!
Alberto V. E. (CRYP - UGR) Steganography April 2010 29 / 38

64. Future
Messages through light
Quantum physics killed the cryptography stars
Idea: Polarized photons cryptosystem... in 1984! [4]
Alberto V. E. (CRYP - UGR) Steganography April 2010 30 / 38

65. Future
Messages through light
Quantum physics killed the cryptography stars
Idea: Polarized photons cryptosystem... in 1984! [4]
Alberto V. E. (CRYP - UGR) Steganography April 2010 30 / 38

66. Future
DNA Coding
Limits?
DNA and RNA have coded
life of living things in a pretty
good way for years.
Let’s use copyright it!
4 nucleic acids:
How?
A: 00
Innocuous sequences.
C: 01
Redundant sequences.
G: 10
Add sequences.
T: 11
Alberto V. E. (CRYP - UGR) Steganography April 2010 31 / 38

67. Future
DNA Coding
Limits?
DNA and RNA have coded
life of living things in a pretty
good way for years.
Let’s use copyright it!
4 nucleic acids:
How?
A: 00
Innocuous sequences.
C: 01
Redundant sequences.
G: 10
Add sequences.
T: 11
Alberto V. E. (CRYP - UGR) Steganography April 2010 31 / 38

68. Future
DNA Coding
Limits?
DNA and RNA have coded
life of living things in a pretty
good way for years.
Let’s use copyright it!
4 nucleic acids:
How?
A: 00
Innocuous sequences.
C: 01
Redundant sequences.
G: 10
Add sequences.
T: 11
Alberto V. E. (CRYP - UGR) Steganography April 2010 31 / 38

69. Conclusions
Index
1 Introduction
2 Past
3 Present
4 Future
5 Conclusions
Alberto V. E. (CRYP - UGR) Steganography April 2010 32 / 38

70. Conclusions
Conclusions
Benefits
Secrecy and confusion.
Variety of combinations.
Can be combined with
cryptography.
Only few pros but strong ones.
Alberto V. E. (CRYP - UGR) Steganography April 2010 33 / 38

71. Conclusions
Conclusions
Cons
Not suitable for massive
transmissions.
Requires more effort than
regular cryptography.
Weak against transformation.
Specific solutions for specific
problems.
Always trade security against
robustness.
Alberto V. E. (CRYP - UGR) Steganography April 2010 34 / 38

72. References
References I
Information Hiding - A Survey
Fabien A. P. Petitcolas, Ross J. Anderson and Markus G. Kuhn
Proceedings of the IEEE, special issue on protection of multimedia
content, 87(7):1062-1078, July 1999
Exploring Steganography: Seeing the Unseen
Neil F. Johnson and Sushil Jajodia.
IEEE Computer, February 1998: 26-34.
Reliable Dectection of LSB Steganography in Color and Grayscale
Images.
Jessica Fridrich, Miroslav Goljan and Rui Du
Multimedia, IEEE, 2001
Alberto V. E. (CRYP - UGR) Steganography April 2010 35 / 38

73. References
References II
Quantum cryptography: Public-key distribution and coin tossing
Bennett, C. H. and Brassard, G.
Proceedings of IEEE International Conference on Computers,
December 1984.
Hiding Data in DNA
Boris Shimanovsky, Jessica Feng and Miodrag Potkonjak
Information Hiding, 2003 - Springer
Disappearing Cryptography. Information Hiding: Steganography &
Watermarking. (3rd ed.)
Peter Wayner.
Elsevier, 2009.
Alberto V. E. (CRYP - UGR) Steganography April 2010 36 / 38

74. References
References III
Matem´ticos, esp´ y piratas inform´ticos. Codificaci´n y
a ıas a o
Criptograf´
ıa.
Joan G´mez
o
RBA, 2010.
Wikipedia: Steganography
http://en.wikipedia.org/wiki/Steganography
Kriptopolis (in Spanish)
http://www.kriptopolis.org/articulos/esteganografia
Steganography: How to Send a Secret Message
http://www.strangehorizons.com/2001/20011008/
steganography.shtml
Johnson & Johnson Technology Consultants (Neil F. Johnson)
http://www.jjtc.com/Steganography/ (software)
Alberto V. E. (CRYP - UGR) Steganography April 2010 37 / 38

75. The end
Thank you.
Questions?
Please be nice
Just one more thing!
Alberto V. E. (CRYP - UGR) Steganography April 2010 38 / 38

76. The end
Thank you.
Questions?
Please be nice
Just one more thing!
Alberto V. E. (CRYP - UGR) Steganography April 2010 38 / 38