Patent ID: 8086862
Filing Date: 2011-12-27
Classification: G06F,H04N

Abstract:
1. A program data file storage method in a broadcast receiver, comprising: authenticating each of data files of a first program included in a first transport stream received by the broadcast receiver, and storing each of the authenticated data files of the first program into the broadcast receiver according to information concerning storage of each of the data files of the first program; receiving information concerning storage of each of data files of a second program included in a second transport stream received by the broadcast receiver; determining, by the broadcast receiver, whether the data files of the second program include a data file that is different from any of the data files of the first program that have been authenticated at a time of storing the first program, wherein the determining is performed by comparing entire data files of the second program with entire corresponding data files of the first program; and executing following procedures when a different data file is included in the second program based on the determining: verifying, with respect only to the different data file included in the second program from among the data files of the second program, whether two hash values are consistent or not, one of the hash values being calculated from the different data file included in the second program and the other hash value being stored in a hash file corresponding to the different data file included in the second program, and avoiding verifying hash values with respect to a data file, other than the different data file included in the second program, from among the data files of the second program; verifying whether a certificate file included in the second program is valid or not; verifying whether a decrypted value and a hash value are consistent or not, the decrypted value being obtained by decrypting a signature value of a signature file included in the second program using a public key of a leaf certificate in the certificate file of the second program, and the hash value being calculated from a hash file located in a top directory of the second program; and authenticating the second program and storing the authenticated second program according to the information concerning storage of each of the data files of the second program, when a following set of conditions are satisfied: the two hash values are verified to be consistent; the certificate file included in the second program is verified to be valid; and the decrypted value and the hash value are verified to be consistent.