Thumbnail image privacy protection method based on image compression and elastic resolution

The invention discloses a thumbnail image privacy protection method based on image compression and elastic resolution. An original image is blocked; secondary division is carried out on each block toobtain subblocks; corresponding degree of random scrambling is carried out on the subblocks in each block according to a requirement of thumbnail resolution; and through combination of JPEG compression and cryptography technologies, different degree of encryption processing is carried out on DC and AC coefficients in 8x8 blocks on which DCT is carried out, thereby obtaining a thumbnail of a publicpart and completely encrypted data of a private part. According to the method, the thumbnail of the public part can be applied to image preview of a network application, and moreover, certain degreeof privacy protection is also provided. Through utilization of the image compression technology, total particularly storage cost of the public part of the encrypted image is reduced, and bandwidth canbe greatly saved. The inven