Other Free Encyclopedias » Online Encyclopedia » Encyclopedia - Featured Articles » Contributed Topics from A-E

Compression in Image Secret Sharing

encryption iss figure coder

Definition: Simultaneous coding and encryption of visual material in image secret sharing, which are used for secure transmission over communication channels.

Image secret sharing (ISS) techniques can be used for secure transmission/distribution of private visual material over untrusted communication channels. However, a different kind of cryptographic solutions may be required when still images and video are to be transmitted via public wireless and mobile networks. In this case, the large volume of input data necessitates the use of complex compression algorithms Following recent advances in digital imaging, coding and encryption technologies, simultaneous coding and encryption of the visual inputs can be achieved .

To allow for secure distribution/sharing of large digital images in wireless or mobile networks, the encryption scheme recently introduced in integrates the pixel-based ISS cryptographic operations and the Joint Photographic Experts Group (JPEG) compression pipeline (Figure 1). Using the discrete-cosine transform (DTC) followed by the zig-zag and quantization operations, the (2,2)-ISS encryption process encrypts the quantized DCT coefficients into two shares which encounter the entropy coder to produce noise-like shares stored in JPEG format. It should be noted that alternative solutions may use different coders e.g. an arithmetic coder or a Huffman coder, instead of the entropy coder in the scheme depicted in Figure 1.

As it is shown in Figure 2, the decryption procedure requires both shares in the input of the entropy decoder to generate decoded shares of zig-zagged, quantized DCT coefficients. After ISS decryption, and inverse quantization, zig-zag and DCT operations, the scheme produces the decoded (decompressed) image. It should be noted that although the employed ISS concept of satisfies the perfect reconstruction property, due to the lossy JPEG quantization process used in the encoding procedure, the output, decoded image in Figure 2 is not identical to the input secret image in Figure 1.

Compton, Arthur Holly [next] [back] Compressed Video Spatio-Temporal Segmentation

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or