| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device which decrypts/executes an encrypted program by making loading of a nonvolatile memory which holds a decryption program unnecessary, and preventing the decrypted program from being observed from the outside. SOLUTION: The semiconductor integrated circuit device 101 prohibits access to a bus port 110a from the outside, permits access to RAMs 104 and 105, and transfers the encrypted program and the decryption program to the RAM 105 when the encrypted program and the decryption program D123a are input in a RAM 105. Then, when the transfer is terminated, the access to the RAM 104 is prohibited and a CPU103a is ordered to execute decryption of the encrypted program using a private key held in a private key holding part 107 and the decryption program 123a and execution of the decrypted program. After termination of the execution, the access to the RAM 105 is prohibited. COPYRIGHT: (C)2009,JPO&INPIT |
