## 6 Discussion  
This paper introduces a communication scheme for unreachable nodes in decentralized networks. This scheme does not rely on third-party platforms such as trusted institutions, is not limited by IP addresses, and can establish a secure transmission channel between any two nodes. In the following, we will discuss each part of the implementation of the communication scheme, discuss its role for the whole system, and finally we analyze and discuss the communication scheme as the whole. First, we will discuss address generation. We define the address generation algorithm and the legitimate address requirements in overlay networks. On the one hand, the implicit information can be used to achieve authentication and transmission encryption with the participation of a centralized trustworthy agency, which prevents attacks such as data  
Figure 20: Success rates of two methods of establishing communication channels at different network size. theft. On the other hand, the address containing the unique key \(i_{uk}\) generated under the calculation of two hash algorithms with the regulation of \(D_{min}\) ensures the randomness of address generation with the generation process consuming computational resources, which prevents the attacks in P2P networks. Specifically, the address pre-generation step uses two different hash functions to do two consecutive hash operations on the randomly generated public key with \(i_{uk}\), which ensures the randomness of the generated addresses. If an attacker wants to pre-generate two node addresses with very similar addresses, assume that he has already selected two \(i_{pub}\) with close logical distance by elliptic curve, but when the two hash functions run as specified by the algorithm are completed, the results will be redistributed in the address space because of the characteristics of the hash functions and the logical distance will not exist, thus preventing the eclipse attack. The \(Dmin\) setting makes address generation require some computation, i.e., continuous computation to obtain the available addresses in the network, which makes it impossible for a particular node to assume a large number of identities in a short period of time, thus preventing sybil attacks. The nodes in the network include the need to verify that the node's identity and address match before any interaction, which prevents an attacker without a legitimate identity from assuming multiple identities to initiate connections to other normal nodes, thus guarding against DDoS attacks. In addition, the implicit mapping relationship between the node address and \(i_{pub}\) makes it possible for both public and confidential message transfers to mutually verify the correctness of the claimed \(i_{pub}\), which fundamentally eliminates \(i_{pub}\) substitution and prevents man-in-the-middle attacks. The signature of the public message transmission after adding a random number to the message and the signature of the confidential message transmission when a symmetric key is passed prevent replay attacks and data tampering. In this way, the security settings in the address generation algorithm achieve malicious node prevention and data security assurance in P2P networks without relying on centralized trusted institutions. Then, we discuss the virtual network, which is the \"skeleton\" of the whole solution, connecting all nodes that contain reachable and unreachable nodes. Instead of a trusted centralized organization, such as a centralized cloud platform, we use overlay network technology to store the indexes of all the nodes in the network, including both reachable and unreachable nodes, decentralized in each reachable node via DHT. In the experiments, a thread-based node simulation close to the real environment is used to simulate the data interaction between nodes through real packet delivery. For network construction, network lookup is evaluated.