Security of new encryption algorithm for image cryptosystems

1
Security of new encryption algorithm for image
cryptosystems

• W-B Lee, T-H Chen and C-C Lee
• The Imaging Science Journal Vol. 54
• September 2005.
• Present by ???

2
Outline

• Introduction
• Review of CHC scheme
• Chosen-plainimage attrack
• Experimental results
• Conclusions

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Introduction

• Review CHC scheme

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Chosen-plainimage attrack
Alice
Sender
S1A
S1A, EKA(C1A)
Public Insecure Channel
Common Codebook CA
Bob
S1B
S1B, EKB(C1B)
Common Codebook CB
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Chosen-plainimage attrack
Alice
S1A, EKA(C1A)
Emulated Codebook CB
S1B, EKB(C1B)
Codebook C1A
4
S1A
4
Public Insecure Channel
16
16
S1B
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Experimental results(1/3)
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Experimental results(2/3)
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Experimental results(3/3)
PSNR values (dB) of reconstructed secret images
from unencrypted index sets using common or
arbitrary codebooks, respectively
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conclusion

• In the present paper, the cases of the
  chosen-plainimage attack is discussed to show why
  it is not good to protect a large number of
  secret images by encrypting common codebook