Patent ID: 8275134

Claim:
A method for guaranteeing security of critical data, said wherein method is used in a terminal comprising a secured chip, an application platform, and a secured input device, and wherein said method comprises: activating the secured chip by the application platform to receive encrypted critical data with key A; parsing internally, by the secured chip, the encrypted critical data with key A with a preset key A to generate a plaintext, then encrypting said plaintext with a preset key B to generate encrypted critical data with key B, and returning the encrypted critical data with key B to the application platform, wherein the preset key A and the preset key B are stored in the security chip; wherein said key A is a private key of the secured chip, said method further comprises: encrypting by the secured input device its own identification information with its own private key; encrypting the encrypted identification information and acquired critical data with a public key corresponding to the key A to obtain the encrypted critical data with key A, and sending the encrypted critical data with key A to the application platform; and the process of parsing the encrypted critical data with key A by the secured chip comprises: parsing the encrypted critical data with key A with the preset key a to obtain the encrypted identification information of the secured input device and critical data; parsing the identification information with the public key of the secured input device; and determining whether the secured input device is a legal secured input device.