Large-capacity hiding method for reversible data in bitstream encryption domain of JPEG image

Abstract

The invention discloses a large-capacity hiding method for reversible data in a bitstream encryption domain of a JPEG image. According to the method, a user performs exclusive or encryption on extension bits of entropy coding in each of image blocks according to an encryption key in JPEG bitstreams, performs pseudo-random scrambling on remaining AC coefficients except a last non-zero AC coefficient, and then performs the pseudo-random scrambling on the entropy coding of all the image blocks; a cloud performs embedding of extraneous information by a histogram shifting method on the AC coefficients in a bitstream ciphertext according to a hiding key, and can perform non-destructive extraction; and a receiver performs pseudo-random scrambling resumption on the entropy coding of ciphertext image blocks in the bitstream ciphertext according to the encryption key, and then the pseudo-random scrambling resumption and exclusive or decryption of the AC coefficients are performed in the entropycoding of each of the ciphertext image blocks to obtain decrypted bitstreams same as original JPEG bitstreams. The method not only achieves encryption of the extension bits of the entropy coding, butalso encrypts Huffman coding of the entropy coding; and the steganographic capacity is large, and the safety is high.

Description

technical field [0001] The invention relates to a large-capacity JPEG image encryption domain reversible data hiding method. Background technique [0002] With the rapid development of cloud computing, the security and privacy protection of digital images stored in the cloud has attracted widespread attention. Image encryption domain reversible information hiding (RDH-EI: Reversible Data Hiding in Encrypted Image) is a method of reversibly hiding additional information in the ciphertext image (encrypted domain) after encrypting the original image, and after the additional information is extracted, the original image A technique that can be reconstructed losslessly. This technology can not only realize the privacy protection of cloud digital images through encryption, but also facilitate its management by hiding additional information in ciphertext images; at the same time, at the receiving end, the recipient can extract additional information and restore the original image....

AI Technical Summary

Problems solved by technology

The above algorithm only uses part of the image block entropy coding (information hiding entropy coding) as the carrier of information embedding, which affects the steganography capacity, and because the hidden entropy coding information is hidden in the JPEG header file, the encrypted bitstream can be decoded to get The size of the encrypted image does not match the original image

[0005] In addition, the encryption method in the above algorithm only performs XOR encryption on the extended bits at the back of the entropy code, and the Huffman code in other parts of the entropy code does not change; making the encryption algorithm a security risk

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