Abstract: Insufficient utilization of image blocks in the existing reversible information hiding methods results in a low embedding capacity of secret information. In order to address this issue, this paper proposes a multiple embedding reversible information hiding algorithm based on block classification. First, the original image is encrypted with a stream cipher, and the encrypted image is further divided into multiple non-overlapping blocks. Subsequently, the Most Significant Bit (MSB) adaptive prediction algorithm is used to predict the first pixel and other pixels in each block, which is marked as a usable block or an unusable block. Finally, the available blocks are reconstructed and embedded with secret data, and the non-available blocks are re-embedded with the Median-Edge Detector (MED) prediction algorithm to realize the embedding of secret information. When the receiver receives the secret image, the secret information is extracted by the data-hiding key, and the original image is restored by the encryption key. Experimental results demonstrate that the proposed method can significantly improve the embedding capacity of secret information embedding, while keeping a high image restoration quality. The overall performance is superior to existing methods in terms of both embedding capacity and image restoration quality.

Key words: reversible information hiding, image encryption, middle edge detector, block classification