Research On Image Secret Sharing Schemes

Image information has developed to such a degree that it is now widely used. With the rapid development of network technology, image information can be distributed and transformed on the Internet rapidly and conveniently. Because of the unsafe network, the image information may be lost or corrupted during the transmission; the plotter also may steal unauthorized image information by means of network. To solve these security problems, image encryption technologies are proposed.Secret sharing is an important part of the cryptography protocols. Since Shamir and Blakley first developed the concept of the (t, n) threshold secret sharing scheme. With the maturity of secret sharing schemes, scholars do many works in this field and apply these schemes to image encryption gradually.In this paper, we choose the verifiable secret sharing and image secret sharing as our priority research areas.. The main contributions of this paper are as follows:(1) The YCH scheme has the following drawbacks:①In construction phase, this scheme has to divide the process into two situations: k≤t and k > t, this classification increases the computation quantity(this scheme is a (t,n) threshold scheme, here k is number of shared secrets);②The scheme can not identify the cheaters no matter she/he is the dealer or participants, so it is unpractical;③The scheme needs a security channel during initialization phase, it is a big-ticket system. Based on YCH scheme and the intractability of discrete logarithm, we propose a new verifiable (t,n) threshold scheme. The new scheme does away with the above drawbacks and still remains advantages of YCH scheme.(2) We propose a general secret sharing scheme to identify cheaters based on Pinch's scheme and the RSA cryptosystem. The new scheme is verifiable and realizes the dynamic property, the system doesn't need security channel. (3) Based on the Thien-Lin scheme proposed in 2002 and the intractability of discrete logarithm, we propose an advanced image secret sharing scheme, and realize the scheme by experiments. In this scheme, because each participant chooses her/his own shadow by her/himself, the scheme is a multi-use scheme; all the sizes of shadow images are less than that of the original secret image, which is useful to do subsequent processing.(4) We analyze the secret sharing scheme using matrix projection proposed by L. Bai, then propose a relatively secure image secret sharing scheme, the new scheme provides a better security measures and reliable recovery methods for image security storage; the image recovery has lossless property.