Dynamic host configuring protocol based security access method and system

The invention discloses a safe access method based on dynamic host computer configuration protocol (DHCP), comprising the steps of: extending DHCP protocol, negotiating DHCP access-used attestation protocol by the extended DHCP protocol; using the negotiated attestation protocol to implement DHCP access attestation. And the invention discloses a safe access system based on DHCP. Because the extended DHCP protocol can negotiate various attestation protocols, it can assure DHCP protocol can use various attestation protocols for attestation, and because the negotiated attestation protocols are based on user name and password mode, it can apply to the existing RADIUS-based AAA framework. Besides, it can improve DHCP-based network access security.