Concerning the problem of security for steganography algorithm, a Diamond Encoding (DE) steganography algorithm based on Algebraic MultiGrid (AMG) was proposed. Firstly, an image was divided into two parts of coarse grid and fine grid by the AMG method. Then, the confidential information was embedded into the two part pixels of coarse grid and fine grid by DE method. The change of pixels in coarse grid part has little influence on the whole image quality, while the change of pixels in fine grid part has the great effect on the whole image quality. And the k value of DE is associated with the capacity of information hiding closely, the pixels change greater with the k value increasing. Therefore, in the embedding process with DE, the k value of the coarse grid part is not less than that of the fine grid part. Finally, when the k value of DE was chosen to 1 and 2, three kinds of steganography scheme were proposed. The proposed algorithm was compared with Least Significant Bit (LSB) replacement, random LSB matching, DE algorithm and adaptive edge detection algorithm. The experimental results show that, the first-order Markov security metric of the proposed algorithm is superior to other contrasted steganalysis algorithms.

The certificate path of the inner-realm is described in its subject alternative name, and the certificate path of the inter-realm was implemented by its proxy. In the same realm, the shortest path can be acquired by the sponsor with comparing the path in the subject alternative name of the target’s certificate and the sponsor’s trusted anchors. In the different realm, the path of the inter-realm can be acquired by requesting the proxy of the construction and concatenating the certificate path described in the subject alternative name, thus the construction of the whole certificate path can be implemented.