Research On Technologies Of I2P Anonymous Network Node Discovery And Anonymous Measurement

With the popularization and development of computer network technology,the risk of personal privacy leakage is increasing,anonymous communication network plays an important role in protecting user privacy security.As one of the most popular anonymous communication networks,I2 P provides strong anonymity for user behavior through encryption and communication strategies,but it also provides convenience for illegal and criminal activities,and many illegal acts are carried out under the protection of I2 P networks.Therefore,the nodes discovery and anonymous measurement of I2 P network can better supervise and evaluate I2 P network,help I2 P network developers refine network models,improve the overall performance and security of I2 P,and better use I2 P networks on the basis of protecting user privacy and security.There are following challenges in current I2 P node discovery and anonymous measurement methods:(1)There is not a central server to manage the global node information in I2 P network,and it is necessary to collect nodes through the I2 P node discovery method,but the method of discovering I2 P nodes through active query has the problem of high repetition rate and low discovery rate of discovery nodes?(2)At present,most of the anonymous measurement techniques are aimed at the general anonymous communication network model,while the routing strategies of different anonymous communication networks are different,and the anonymous measurement technology for the general anonymous communication network model cannot accurately measure the anonymity of the I2 P network.In view of the above problems,there are following three aspects in the main research work of this thesis:(1)Optimize the node active query method,adopt the method of constructing the query routing key based on k-bucket,and no longer recursive query for the same routing key in the query process,which improves the node discovery rate and reduces the node discovery repetition rate in the active query process.Experiments show that the node discovery rate is increased by 19.18% and the node discovery duplication rate is reduced by 3.59% through using the optimized active query method?(2)Establish a message rerouting model to measure the anonymity of I2 P networks.Based on the I2 P routing strategy,the model analyzes the posterior probability of potential senders(or receivers)of communication messages from the perspective of attackers,uses the relative entropy of the posterior probability to quantify the anonymity of I2 P networks,and uses the probability of attackers colluding to successfully crack the tunnel to indicate the ability of I2 P networks to resist attacks.Experiments show that with the increase of the number of messages,the average relative error between the predicted value and the real value of the measurement model is stable at about 4%,and the average accuracy of the model measurement reaches more than 96%.;(3)Based on the research results of I2 P node discovery and anonymous measurement,the I2 P node discovery and anonymous measurement system is designed and implemented,and the I2 P node information is collected in current time by using the node discovery method of three ways: comprehensive node replenishment,node passive collection and node active query,and uses it as the input of the measurement model to measure the anonymity of the current I2 P network.The results of node discovery show that Floodfill nodes account for about 8.4% of the total number of discovery nodes in the I2 P network,and the country distribution of I2 P nodes is uneven,mostly concentrated in developed countries in Europe and the United States.The anonymous metric experiment shows that the probability of successful conspiracy attacks by attackers at the single country level is low,but when European and American countries jointly carry out collusion attacks,they can de-anonymize user nodes with a probability of 47.51%.