Secret segmentation VPN

Secret segmentation is when the information is separated into a lot of pieces, and every piece doesn’t have the individual meaning. However, on combining these pieces, the complete information is restored. This idea is used on the image encryption. Firstly, at the sending end, the image is divided into many pieces according to some algorithms, and these pieces are given to the different people. At the receiving end, if all people participate, the image could be restored. The type of the techniques has the higher security, but  it has a fatal shortcoming that any piece can’t loss.Based on the concept of sharing a key presented by Shamir [13] in 1979, the secret sharing technique is proposed. The key K is divided into n subkeys ki (0 ≤ i ≤ n). If there are k (k is the threshold) subkeys, K can be gained. If the number of subkeys is less than k, Kcannot be gained. In this field, Shamir [13], Naor [14], and Cao [15] et al. have done many pioneering works. Although this kind of method allows subkeys to lose partially, the requirement of subkey integrity is still higher. Therefore, these algorithms are used seldom in practice.