Abstract: Provided is a classifier training method, including: acquiring a training sample set; determining a classification condition at a root node according to a preset classification condition feature, performing classification on training samples in the training sample set according to the classification condition at the root node, and acquiring a classification subset corresponding to a child node of the root node; using the child node of the root node as a current node, circularly implementing the step of determining a classification condition at the current node according to another preset classification condition feature, performing classification on training samples in a classification subset corresponding to the current node according to the classification condition at the current node, and acquiring a classification subset of a child node of the current node, till a leaf node; and determining a user identity classification result at the current node, and obtaining a decision tree classifier.

Abstract: Provided is a classifier training method, including: acquiring a training sample set; determining a classification condition at a root node according to a preset classification condition feature, performing classification on training samples in the training sample set according to the classification condition at the root node, and acquiring a classification subset corresponding to a child node of the root node; using the child node of the root node as a current node, circularly implementing the step of determining a classification condition at the current node according to another preset classification condition feature, performing classification on training samples in a classification subset corresponding to the current node according to the classification condition at the current node, and acquiring a classification subset of a child node of the current node, till a leaf node; and determining a user identity classification result at the current node, and obtaining a decision tree classifier.

Abstract: Disclosed are a verification method, apparatus, server and system. The method includes: receiving a service request from a terminal; acquiring service data according to the service request received from the terminal; generating a verification question and a standard answer according to the service data; and interacting with the terminal according to the verification question and the standard answer to complete a verification process. The verification question and the standard answer are generated according to the service feature of the service requested by the terminal, and interaction is performed with the terminal according to the verification question and the standard answer to complete the verification process, thereby solving the problem that the network service security cannot be ensured using the verification code technology due to attacks launched by combining the machine and the manpower.