Computational cryptography based on trigonometric algorithms and intensity superposition

Abstract

A computational technique for visual cryptography is presented. This technique is performed by means of trigonometric algorithms and intensity superposition. The encryption is carried out by encoding an image in a trigonometric identity. This procedure generates a peaks pattern and a characteristic random image. Based on the optical superposition, these two images are overlapped to obtain the encryption pattern. Thus, the encryption procedure is completed. To perform the decryption, the peaks pattern is retrieved from the encryption. From this pattern, a cosine pattern is generated. Then, the phase is detected from this pattern to obtain the original image. Thus, the decryption is completed and the original image is retrieved. The cryptography is performed in experimental form by scanning printed images for encryption and decryption. The viability of this technique is described based on the decryption quality and the encryption robustness. This computational performance represents a contribution in the field of the optics and visual cryptography. The technique is tested with real scenes and its results are presented in computational form and in experimental form.

Keywords:

• IMAGE ENCRYPTION AND DECRYPTION
• INTENSITY SUPERPOSITION
• PHASE DETECTION