Steganography: Hiding information in past, present and future.

SteganographyHiding information in past, present and future.

Alberto Villegas [email protected]

CryptographyUniversity of Granada

April 2010

Alberto V. E. (CRYP - UGR) Steganography April 2010 1 / 38

Review

Concepts reviewPreviously 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.


Review

TodaySteganography

What is Steganography?We will review the topic through history

1 Past: historical examples.

2 Present: digital era.

3 Future: no-that-much science fictionideas.


Review

Index

1 Introduction2 Past3 Present4 Future5 Conclusions


Introduction

Index



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.


Introduction

Stegano... what?





Error!





Introduction

Stegano... what?





Error!





Introduction

Stegano... what?





Error!





Introduction

Stegano... what?





Error!





Introduction

SteganographyDefinition

Steganography

Art and science of writing hidden messages in such a way that no onesuspects the existence of the message.

But, then, what is the difference withCryptography?“Cryptography is about protecting thecontent of messages, steganography isabout concealing their very existence” [1]


Introduction

SteganographyDefinition

Steganography

Art and science of writing hidden messages in such a way that no onesuspects the existence of the message.

But, then, what is the difference withCryptography?“Cryptography is about protecting thecontent of messages, steganography isabout concealing their very existence” [1]


Introduction

SteganographyTerminology [1]

Embedded data (M): the message that one wishes to send secretly.

Cover-text (O): (covert-image or cover-audio) innocuous messageused 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


Introduction






M × O × K → M


Introduction






M × O × K → M


Introduction






M × O × K → M


Introduction






M × O × K → M


Introduction

SteganographyModel (I)

Figure: Steganography abstract process


Introduction

SteganographyModel (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 twoweeks ago.


Introduction

SteganographyWho is it for?

Who is using steganographynowadays?

Spies: intelligence andcounterintelligence agences.

Militaries: unobtrusivecommunications.

Terrorists: “it arouses lesssuspicion” - John Wilkins (1641)

Copyright: watermarks andfingerprints.

SPAM: email forgery.

Only the good guys!(actually, is not that bad)


Introduction










Introduction










Introduction










Introduction










Introduction










Introduction










Introduction










Introduction

SteganographyExamples?

Stop!

Could someone give an example of Steganography right now?

My recommendation

Think before going deeperinto a topic.

Think about what happenedso far.


Introduction


Stop!


My recommendation




Introduction


Stop!


My recommendation




Past

Index



Past

ChinaSilk passion

Paper masks: The sender and the receiver shared copies of a papermask with a number of holes cut at random locations (keep this inmind).

Wax balls: The also wrote messages on silk and encased them in ballsof wax. The wax ball could then be hidden in the messenger.


Past

Greece#HerodotusFacts

Shaved slaves: messageswere written over slavesheads. Still in 20thcentury!

Wax tablet: a goodexample of camouflageover unsuspicious diaryobjects.


Past

MusicStego-heros

Gaspar Schott (17thcentury): music notescoding letters.

John Wilkings (17thcentury): talkingmusicians.

J. S. Bach (17th-18th century):embedded his name in the organchorale “Vor deinen Thron”using the rule: if the i-th note ofthe scale occurs k times, thenthe k-th letter of the alphabet isto be entered in the i-th place.


Past

WritingAcrostic, morse and more.

A boat, beneath a sunny skyLingering onward dreamilyIn 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:Echoes fade and memories die:Autumn frosts have slain July.Still she haunts me, phantomwise,Alice moving under skiesNever seen by waking eyes.Children yet, the tale to hear,Eager eye and willing ear,Lovingly shall nestle near.In a Wonderland they lie,Dreaming as the days go by,Dreaming as the summers die:Ever drifting down the stream -Lingering in the golden gleam -Life, what is it but a dream?

Acrostic: messages hidden intext using patterns.

Morse Code with {i, j, f, t}:another good example ofcamouflage over unsuspiciousdiary objects.

Is Father Dead or Deceased?


Past







Past







Past







Past







Past

Invisible Ink

Lemon, urine: after burnedreleased carbon shows up.

Refined with chemistry: saltammoniac dissolved in water.

Refined with biology: somenatural unique responses.

Wait a second...


Past

Invisible Ink

Lemon, urine: after burnedreleased carbon shows up.

Refined with chemistry: saltammoniac dissolved in water.

Refined with biology: somenatural unique responses.

Wait a second...


Past

Publishing

Not only for war

Steganography has protected copyright even when it did not exists.

Intended gaps: Falseintended data.

Microdots: imperceptibledots.

Line spacing: modernpublishing.


Present

Index



Present

Digital EraFollow the white rabbit

Digital era: how do wemanage data now?

Sound: bit streams.

Images: bit streams.

Video: bit streams.

Text: bit streams.

Noise

A weak spot to exploit.


Present



Sound: bit streams.


Video: bit streams.

Text: bit streams.

Noise



Present



Sound: bit streams.


Video: bit streams.

Text: bit streams.

Noise



Present



Sound: bit streams.


Video: bit streams.

Text: bit streams.

Noise



Present



Sound: bit streams.


Video: bit streams.

Text: bit streams.

Noise



Present



Sound: bit streams.


Video: bit streams.

Text: bit streams.

Noise



Present

A simple ideaTake a closer look


Present

A simple ideaA said CLOSER!

(a) #18657E (b) #19657E (c) #1A657E (d) #1B657E

Figure: LSB variations over R


Present

LSB SteganographyI have discovered a truly marvelous proof of this, which this pixel is too narrow to contain.

(a) #18667D

(b) #1B657E

LSB Steganography

LSB Variations are indiscernible.Even the two LSB!

Let’s check a poor 800× 600 image.

800× 600 = 48000pixels

480000pixels × 6 = 2880000bit

2880000bit

8bit/character= 360000characters


Present


(c) #18667D

(d) #1B657E

LSB Steganography



800× 600 = 48000pixels

480000pixels × 6 = 2880000bit

2880000bit



Present


(e) #18667D

(f) #1B657E

LSB Steganography



800× 600 = 48000pixels

480000pixels × 6 = 2880000bit

2880000bit



Present


(g) #18667D

(h) #1B657E

LSB Steganography



800× 600 = 48000pixels

480000pixels × 6 = 2880000bit

2880000bit



Present

LSB Steganography

Pros

Easy to understand and code.

Pure steganographic (a priori).

Lot’s of coding chances. [3]

Cons

Weak against noise attack.

Requires good images.

Requires non-coded images.


Present

WattermarkingCopyrigthing

Problem

Lossy compression (JPEG,MGEP) destroys LSB variations.

Solution

Hide in other LSB.

Also indiscernible for human eye.


Present


Concepts

Visible watermarking.

Invisible watermarking.

Requires redundancy!

Also valid for video compression.


Present


Concepts






Present


Concepts






Future

Index



Future

Science fiction?Keep your mind open

Where are the limits?

Science and engineering developfast.

Multiple fields merge and splitcontinuously.

What can we learn from other fields?

Keep your mind open!


Future

Science fiction?Keep your mind open

Where are the limits?

Science and engineering developfast.

Multiple fields merge and splitcontinuously.

What can we learn from other fields?

Keep your mind open!


Future

Messages through lightQuantum physics killed the cryptography stars

Idea: Polarized photons cryptosystem... in 1984! [4]


Future

Messages through lightQuantum physics killed the cryptography stars

Idea: Polarized photons cryptosystem... in 1984! [4]


Future

DNA CodingLimits?

DNA and RNA have codedlife of living things in a prettygood way for years.

Let’s use copyright it!

4 nucleic acids:

A: 00

C: 01

G: 10

T: 11

How?

Innocuous sequences.

Redundant sequences.

Add sequences.


Future

DNA CodingLimits?



4 nucleic acids:

A: 00

C: 01

G: 10

T: 11

How?



Add sequences.


Future

DNA CodingLimits?



4 nucleic acids:

A: 00

C: 01

G: 10

T: 11

How?



Add sequences.


Conclusions

Index



Conclusions

Conclusions

Benefits

Secrecy and confusion.

Variety of combinations.

Can be combined withcryptography.

Only few pros but strong ones.


Conclusions

Conclusions

Cons

Not suitable for massivetransmissions.

Requires more effort thanregular cryptography.

Weak against transformation.

Specific solutions for specificproblems.

Always trade security againstrobustness.


References

References I

Information Hiding - A SurveyFabien A. P. Petitcolas, Ross J. Anderson and Markus G. KuhnProceedings of the IEEE, special issue on protection of multimediacontent, 87(7):1062-1078, July 1999

Exploring Steganography: Seeing the UnseenNeil F. Johnson and Sushil Jajodia.IEEE Computer, February 1998: 26-34.

Reliable Dectection of LSB Steganography in Color and GrayscaleImages.Jessica Fridrich, Miroslav Goljan and Rui DuMultimedia, IEEE, 2001


References

References II

Quantum cryptography: Public-key distribution and coin tossingBennett, C. H. and Brassard, G.Proceedings of IEEE International Conference on Computers,December 1984.

Hiding Data in DNABoris Shimanovsky, Jessica Feng and Miodrag PotkonjakInformation Hiding, 2003 - Springer

Disappearing Cryptography. Information Hiding: Steganography &Watermarking. (3rd ed.)Peter Wayner.Elsevier, 2009.


References

References III

Matematicos, espıas y piratas informaticos. Codificacion yCriptografıa.Joan GomezRBA, 2010.

Wikipedia: Steganographyhttp://en.wikipedia.org/wiki/Steganography

Kriptopolis (in Spanish)http://www.kriptopolis.org/articulos/esteganografia

Steganography: How to Send a Secret Messagehttp://www.strangehorizons.com/2001/20011008/steganography.shtml

Johnson & Johnson Technology Consultants (Neil F. Johnson)http://www.jjtc.com/Steganography/ (software)


http://en.wikipedia.org/wiki/Steganography

http://www.kriptopolis.org/articulos/esteganografia

http://www.strangehorizons.com/2001/20011008/steganography.shtml

http://www.strangehorizons.com/2001/20011008/steganography.shtml

http://www.jjtc.com/Steganography/

The end

Thank you.

Questions?Please be nice

Just one more thing!


The end

Thank you.

Questions?Please be nice

Just one more thing!
