An encrypted image search method supporting group sharing and key update in cloud storage environment

Abstract

The invention relates to an encrypted image search method in support of group sharing and key update in a cloud storage environment. Image owners encrypt images to obtain ciphertexts by employing a symmetric encryption algorithm; image feature vectors are encrypted by using master keys, thereby obtaining feature vector descriptors; the ciphertexts and the feature vector descriptors are uploaded to a cloud; and the image owners distribute keys to groups for search authorization. Licensed users generate search requests by employing extracted encrypted image feature vectors. A trustable center processes the requests to generate search trap doors. The cloud compares the distance between the search trap doors and the feature descriptors in an image set, and returns the encrypted images with the minimum distance to the users. According to the method, trustable center management group keys are established; when user keys are abnormal, the trustable center updates the abnormal user key and key attachment information pairs; and the ciphertexts are unnecessarily encrypted again by the image owners. According to the method, the calculation overheads can be effectively reduced, the verification efficiency is improved, and the privacy security is ensured.

Description

technical field [0001] The invention relates to the field of image search, in particular to an encrypted image search method that supports group sharing and key update in a cloud storage environment. Background technique [0002] In the study of image search in cloud computing storage, content-based encrypted image search is an important technology in cloud storage services. That is to use image feature extraction technology to perform encrypted image search operations under encrypted conditions. The cloud server does not touch any plaintext, ensuring the security and searchability of images. The cloud determines the similarity of encrypted images during the image search process by calculating and comparing the distance between the global feature vectors between encrypted images. In a social group, when an image owner shares an image, he needs to assign a corresponding image search key to the users in the group at the same time. If the user key is abnormal or leaked, the i...

AI Technical Summary

Problems solved by technology

When the key is abnormal, in order to ensure the security of the encrypted image, the image owner needs to perform an update operation, which causes not only the key but also the corresponding ciphertext to be updated synchronously, which will generate a lot of interaction and calculation

The existing update operation methods require the image owner to regenerate the search key and update the ciphertext at the same time. This method is suitable for very few updates

In addition, since images express more information, especially in cloud environments that are not completely trusted, with the increasing number of image sets, there will be huge key anomalies in the encrypted image search process, which will also lead to huge interactions and Computational overhead

Therefore, the search efficiency of encrypted images needs to be improved urgently

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