Patent ID: 8060749

Claim:
An authenticated program execution method, comprising: authenticating a program included in a transport stream and storing the authenticated program into a broadcast receiver according to information concerning storage of each data file of the program; and executing the authenticated stored program, wherein the authenticating and storing comprises executing authentication operations that include: verifying whether two hash values are consistent, one hash value of the two hash values being calculated from each data file included in the program and an other hash value of the two hash values being stored in a hash file corresponding to said each data file; verifying whether a certificate file included in the program is valid; verifying whether a decrypted value and a hash value are consistent, the decrypted value being obtained by decrypting a signature value of a signature file included in the program using a public key of a leaf certificate included in the certificate file of the program, the hash value being calculated from a hash file located in a top directory of the program; and authenticating the program and storing each data file of the authenticated program according to the information concerning storage without executing the authenticated program, in the case where all of the following are satisfied: the two hash values are verified to be consistent; the certificate file is verified to be valid; and the decrypted value and the hash value are verified to be consistent, wherein the executing the authenticated stored program comprises: re-executing, when the stored program is executed, on the stored program, the verifying whether the certificate file included in the program is valid, among processes that include the verifying whether the two hash values are consistent, the verifying whether the certificate file included in the program is valid, and the verifying whether the decrypted value and the hash value are consistent, the processes having been performed on the stored program; and re-authenticating the stored program and executing the re-authenticated stored program only in the case where the certificate file included in the stored program is verified to be valid, wherein the authenticating and storing the program includes executing all of the authentication operations without executing the program, and the executing the authenticated stored program includes executing at least one and less than all of the authentication operations, and wherein, when the program has a directory structure: each data file included in each directory and the hash file corresponding to said each data file are located in a same directory; and verifying whether two hash values are consistent is executed for each data file included in each directory.