Image Encryption and Decryption System using Frequency Phase Encoding and Phase Wrapping Method

주파수 위상 부호화와 위상 랩핑 방법을 이용한 영상 암호화 및 복호화 시스템

  • Seo, Dong-Hoan (Division of Electrical & Electronics Engineering, Korea Maritime University) ;
  • Shin, Chang-Mok (School of Electrical Engineering & Computer Science, Kyungpook National University) ;
  • Cho, Kyu-Bo (School of Electrical Engineering & Computer Science, Kyungpook National University)
  • 서동환 (한국해양대학교 전기전자공학부) ;
  • 신창목 (경북대학교 전자전기컴퓨터학부) ;
  • 조규보 (경북대학교 전자전기컴퓨터학부)
  • Published : 2006.12.25


In this paper, we propose an improved image encryption and fault-tolerance decryption method using phase wrapping and phase encoding in the frequency domain. To generate an encrypted image, an encrypting key which denotes the product of a phase-encoded virtual image, not an original image, and a random phase image is zero-padded and Fourier transformed and its real-valued data is phase-encoded. The decryption process is simply performed by performing the inverse Fourier transform for multiplication of the encrypted key with the decrypting key, made of the proposed phase wrapping method, in the output plane with a spatial filter. This process has the advantages of solving optical alignment and pixel-to-pixel mapping problems. The proposed method using the virtual image, which does not contain any information from the original image, prevents the possibility of counterfeiting from unauthorized people and also can be used as a current spatial light modulator technology by phase encoding of the real-valued data. Computer simulations show the validity of the encryption scheme and the robustness to noise of the encrypted key or the decryption key in the proposed technique.


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