In order to improve the accuracy of Visual Question Answering （VQA） model in answering complex image questions， a Cross-modal Chiastopic-fusion Attention Network （CCAN） for VQA was proposed. Firstly， an improved residual channel self-attention method was proposed to pay attention to the image， and to find important areas according to overall information of the image， thereby introduced a new joint attention mechanism that combined word attention and image area attention； secondly， a “cross-modal chiastopic-fusion” network was proposed to generate multiple features to integrate the two dynamic information flows together， and an effective attention flow was generated in each modal. Among them， element-wise multiplication method was used for joint features. In addition， in order to avoid an increase in computational cost， parameters were shared between networks. Experimental results on VQA v1.0 dataset show that the accuracy of the proposed model reaches 67.57%， which is 2.97 percentage points higher than that of MLAN （Multi-level Attention Network） model， 1.20 percentage points higher than that of CAQT （Co-Attention network with Question Type） model. The proposed method effectively improves the accuracy of visual question answering model. The effectiveness and robustness of the method are verified.

The Wireless Transport Layer Security (WTLS) handshake protocol was built based on digital certificate mechanism. However, there exist several flaws in WTLS. For example, both the communication and computation overload are high. Moreover, it does not verify the server certificate on-line. In order to solve these issues, an improved WTLS handshake protocol based on Identity-based Cryptosystem (IBC) was proposed. It is constructed based on ID, and IDs are exchanged between server and client instead of certificates. Identity-based Encryption (IBE), Identity-based Signature (IBS) and Identity-based Authenticated Key Agreement (IBAKA) were adopted to implement security functions of encryption, signature and key agreement respectively. Sender's ID information was embedded into encryption key computation, which can be used to authenticate the source of message. The analysis on security and efficiency shows that the efficiency of wireless communication is improved without security loss.