Joint Hamming Coding for High Capacity Lossless Image Encryption and Embedding Scheme

Encryption is a widely used solution to prevent privacy leakage and illegal spread when sensitive images are uploaded to cloud storage. Hiding technology also allows confidential data to be embedded into encrypted images for secret communication. As image accuracy without distortion is essential within certain fields (such as medicine and the military), sensitive images must be completely decrypted back into the original images. However, an encrypted image is a noise-like pattern that is meaningless to a user; thus, it is difficult for a user to find the accurate image they desire. Take keywords as search indexes and embed them in encrypted images for encrypted image retrieval as an example. This idea has been extended by Chen and Line’s scheme to achieve higher capacity with reversibility. The proposed scheme adjusts the coding results according to smooth and complex images to increase its hiding capacity. In addition, two thresholds are designed to adjust the predicted pixel value to be close to the original one. Experiments show that compared with the other schemes, the proposed method achieves superior results. In addition, a hidden encrypted image can be extracted from the cover image. Afterward, the hidden secrets can be completely extracted, and sensitive images can also be perfectly restored.