Since the concept of the proxy signature scheme was proposed by it is widely used for people to delegate their own power to others. So far, the proxy signature scheme is only applied in special time period, such as when the original signer is not in his office or when he travels outside. Then, the original signer will use the same secret proxy key in the next special time period. However, those proxy schemes appear to be secure today, they may be exploded in the future while the secret key is exposed. As far as the author is aware, this type of proxy signature schemes with forward-secure ability has not appeared in the literature. Therefore, a proxy signature scheme with the forward-secure ability is proposed in this article. It provides not only the original signer secure keys with forward-secure ability but also the proxy signers secure keys with the forward-secure ability.

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With the characteristic that the commutativity of modular exponential function makes the specific order of secret distribution process less important and on basis of the abstruseness of discrete logarithm, this paper proposed a new secret sharing scheme. In the scheme, the participants themselves select the private keys, which can avoid the distributor's fraud and reduce the distribution's burden as well as ensure the scheme's reuse. The credible participants can join in or leave the participants collection at any time without restarting the scheme procedures.

Versatile video coding (VVC), a new generation video coding standard, achieves significant improvements over high efficiency video coding (HEVC) due to its added advanced coding tools. Despite the fact that affine motion estimation adopted in VVC takes into account the translational, rotational, and scaling motions of the object to improve the accuracy of interprediction, this technique adds a high computational complexity, making VVC unsuitable for use in real-time applications. To address this issue, an adjacency encoding information-based fast affine motion estimation method for VVC is proposed in this paper. First, this paper counts the probability of using the affine mode in interprediction. Then we analyze the trade-off between computational complexity and performance improvement based on statistical information. Finally, by exploring the mutual exclusivity between skip and affine modes, an enhanced method is proposed to reduce interprediction complexity. Experimental results show that compared with the VVC, the proposed low-complexity method achieves 10.11% total encoding time reduction and 40.85% time saving of affine motion estimation with a 0.16% Bjøontegaard delta bitrate (BDBR) increase.