Design of cascaded phase keys for hierarchical security system

Chia H. Yeh, Hsuan T. Chang, Hung C. Chien, Chung J. Kuo

Research output: Contribution to journalArticlepeer-review


An image cryptosystem based on multiple phase-only computer-generated masks is proposed. The proposed cryptosystem is a hierarchical security system that uses multiple phase keys to produce multiple output images. The distant parameters between the phase keys are introduced to increase the system security. The proposed system achieves higher security because the phase keys must have their corresponding order and correct distant parameters to obtain the target image. The proposed system is safe even when an illegal user steals the whole phase keys but without the correct order and distant parameters. Aside from data encryption, the proposed system can also provide safe verification to identify the identity of the persons. The decryption process can be performed in digital methods or implemented by optics for the high speed. Simulation results are demonstrated to verify the proposed method.

Original languageEnglish
Pages (from-to)372-380
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2002
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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