A Robust Coverless Image Steganography Algorithm Based on Image Retrieval with SURF Features
Algorithm 2
Secret Information Extraction.
Input: Stego images , sorted image database IMG,
Output: Secret information S
(1)
Generate multiple sub-CIDs I = , using sorted image database IMG and Key
(2)
for k = 1: do
(3)
Generate a hash sequence for each image based on the order of the sequence
(4)
end for i = 1: n do
(5)
Compute the SURF of the stego image
(6)
For each received image , match it with the most similar original image
(7)
Find the hash sequence corresponding to the image
(8)
(9)
get
(10)
end for
(11)
Calculate the zero-padding information (if it exists)
(12)
Remove the number of trailing zeros from the last segment of the secret information, concatenate the secret information fragments, and obtain the complete secret information S
