Key distribution method

The invention claims a key distribution method, applied to the next generation network, mainly comprising the following steps: a terminal) to exchange transmission login request message; b) exchange by the authentication request message to, certificationc) certification and authentication to the terminal, pulse generating to the terminal and exchange session key, comprising a registration and authentication, the industrial the session key a terminal distribution of softswitch. Wherein the invention realizing sending key of a register certification process, a communication load is smaller, which vertically connected in NGN networks, wherein at the same time to of the integral system for security problem efficiency, the centralism distribution of registration and authentication key of terminal is a small in NGN actual network situation.