Boxed Safe Ambients with Password and Application on the Internet

This page puts forward boxed safe ambients with password (BSAP), it is improved from mobile ambients (MA), which can solve the side effect from open operation and strengthen the control capability of its own boundary in MA. Compared to MA, BSAP has the following advantages: 1) cancels open operation in MA and adds the communication operation primitive between ambients and sub-ambients; 2) adds in, out operation and adds password to in, out, in, out operations; 3) adds the operation primitive del of ambient reclamation. In the end this page uses BSAP to describe and emulate the E-mail system, and gives a solution for the dead-lock process.