Method for verifying legality of cloud shields in long-distance mode

The invention relates to a method for verifying the legality of cloud shields in a long-distance mode. The method includes the following steps that first, four non-modifiable data are stored in each cloud shield when the cloud shield leaves a factory, and the four data comprise A, a root public key PKr, B, an initial secret key pair SK0/PK0, C, the cloud shield ID and D, an initial public key signed by a root private key SKr; second, the legality of each cloud shield can be verified by transmitting the following three sets of data, namely SKr (PK0), SK0 (ID) and SK0 (PK user public key), and the SKr (PK0) is used for verifying the legality of a PK0 source; if the SK0 (ID) can be decoded to obtain the corresponding ID, the ID is from the same cloud shield. The method for verifying the legality of cloud shields in the long-distance mode has the advantages that due to the fact that the SKr (PK0) is signed by the SKr when leaving the factory, hackers cannot falsify the data; the PK0 source legality is determined, and as long as the SK0 (ID) can be decoded to obtain the ID, the ID and the PK0 are from the same cloud shield; the PK0 source legality is determined, as long as the SK0 (PK user public key) can be decoded, the PK is a user public key which must be from one legal cloud shield, and therefore it is guaranteed that the user public key PK cannot be falsified by hackers.