Color Image Encryption in YCbCr Space

WCSP2016

1Beijing Electronic Science and Technology Institute

GOCPCCC Key Laboratory of Information Security2Xidian University

Corresponding authors: {jinxin,lxd}@besti.edu.cn

Beijing Electronic Science and Technology Institute

Xin Jin1, Sui Yin1, Xiaodong Li1, Geng Zhao1, Zhaohui Tian2, Nan Sun1, Shuyun Zhu2

Outline

Motivation1

Preliminaries2

Color Image Encryption in YCbCr Space3

Results and Security Analysis4

Conclusion and Discussion5

2

Motivation

3

R

G

B

Motivation

Y

Cb

Cr

?

?

?

4

Outline

Motivation 1

Preliminaries2

Color Image Encryption in YCbCr Space3

Results and Security Analysis4

Conclusion and Discussion5

5

Preliminaries

RGB→YCbCrr

1D Logistic map

2D Arnold cat map

3D Lu map

DNA Computing

6

Preliminaries

RGB YCbCr

7

B

G

R

Cr

Cb

Y

071.0368.0439.0

439.0291.0148.0

098.0504.0257.0

128

128

16

Cr

Cb

Y

B

G

R

000.00017.2164.1

813.0392.0164.1

596.1000.0164.1

128

128

16

Preliminaries

1D Logistic map

8

Preliminaries

2D Arnold cat map

9

Preliminaries

3D Lu Map

a = 36, b = 3, c = 20

10

Preliminaries

DNA Encoding

C

000110118 bit Pixel

G

A T00 11

01 10

11

Preliminaries

DNA Computing

+ T A C GTACG

CGTA

GCAT

TACG

ATGC

— T A C GTACG

CATG

GCAT

TGCA

ATGC

X Complement(X)

ATCG

TAGC

12

Outline

Motivation 1

Preliminaries2

Color Image Encryption in YCbCr Space3

Results and Security Analysis4

Conclusion and Discussion5

13

Color Image Encryption in YCbCr

14

Color Image Encryption in YCbCr

15

The Y Channel

Y Confusion

Result

Diffusion

Result

Color Image Encryption in YCbCr

16

The CbCr Channel

Cb Channel

DNAEncoding

Ab

DNAAddition

B

Complement

Bcomp

DNADecoding

Cipher Image D

1D Logistic Map

(X’,Y’)

1D Chaotic Map

Z

Outline

Motivation 1

Preliminaries2

Color Image Encryption in YCbCr Space3

Results and Security Analysis4

Conclusion and Discussion5

17

The Encryption Results

18

Key Space

19

The precision of 64-bit double data is 10−15

The key space is about (1015)8 = 10120 ≈ 2399

The max key space of AES = (2256)

Sensitivity of Secret Key

20

dubao Cipher dubao Decrypted with wrong key

The Histogram Analysis

21

The Information Entropy

22

YCbCr H(m) L*a*b* H(m) RGB H(m)

Y 7.9996 L* 7.9961 R 7.9815

Cb 7.9998 a* 7.9952 G 7.9815

Cr 7.9997 b* 7.9815 B 7.9815

The Correlation Analysis

23

The Speed of the Encryption and Decryption

24

128 256 384 512 6400

1

2

3

4

5

6

image size

tim

e c

on

su

mp

tio

n(s

eco

nd

)

speed test

Encryption time in YCbCr

Decryption time in YCbCr

Encryption time in L*a*b*

Decryption time in L*a*b*

Encryption time in RGB

Decryption time in RGB

The Speed of the Encryption and Decryption

25

128 256 384 512 6400

0.05

0.1

0.15

0.2

0.25

0.3

0.35

image size

tim

e c

on

su

mp

tio

n(s

eco

nd

)speed test

YCbCr2RGB time

RGB2YCbCr time

L*a*b*2RGB time

RGB2L*a*b* time

Outline

Motivation 1

Preliminaries2

Color Image Encryption in YCbCr Space3

Results and Security Analysis4

Conclusion and Discussion5

26

Conclusion and Discussion

• A color image encryption algorithm in YCbCr

space.

• In future work, we will utilize the fast speed of the

YCbCr method and continue to improve the

encryption algorithm to have a better and faster

way.

27

Thanks！

WCSP2016

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