23 research outputs found
StyleGAN Encoder-Based Attack for Block Scrambled Face Images
In this paper, we propose an attack method to block scrambled face images,
particularly Encryption-then-Compression (EtC) applied images by utilizing the
existing powerful StyleGAN encoder and decoder for the first time. Instead of
reconstructing identical images as plain ones from encrypted images, we focus
on recovering styles that can reveal identifiable information from the
encrypted images. The proposed method trains an encoder by using plain and
encrypted image pairs with a particular training strategy. While
state-of-the-art attack methods cannot recover any perceptual information from
EtC images, the proposed method discloses personally identifiable information
such as hair color, skin color, eyeglasses, gender, etc. Experiments were
carried out on the CelebA dataset, and results show that reconstructed images
have some perceptual similarities compared to plain images.Comment: To appear in APSIPA ASC 202
Bitstream-Based JPEG Image Encryption with File-Size Preserving
An encryption scheme of JPEG images in the bitstream domain is proposed. The
proposed scheme preserves the JPEG format even after encrypting the images, and
the file size of encrypted images is the exact same as that of the original
JPEG images. Several methods for encrypting JPEG images in the bitstream domain
have been proposed. However, since some marker codes are generated or lost in
the encryption process, the file size of JPEG bitstreams is generally changed
due to the encryption operations. The proposed method inputs JPEG bitstreams
and selectively encrypts the additional bit components of the Huffman code in
the bitstreams. This feature allows us to have encrypted images with the same
data size as that recoded in the image transmission process, when JPEG images
are replaced with the encrypted ones by the hooking, so that the image
transmission are successfully carried out after the hooking.Comment: to appear in 2018 IEEE 7th Global Conference on Consumer Electronics,
Nara, JAPAN, 10th Oct., 201