| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent data and an instruction in secure memory space from being read out to the outside but not to protect a memory at a conventional privilege mode and to avoid ill usage performed in conventional technology. <P>SOLUTION: When data is transferred from user memory space 110 to a general-purpose register 103, a value of a secure information part 104 is set to a security unnecessary state. When data is transferred from secure memory space 120 to the general-purpose register 103, the value of the secure information part 104 is set to a security necessary state. Data transfer from the general-purpose register 103 to user memory space 110 when the value of the secure information part 104 is in the security necessary state is controlled to be inhibited. Thus, a cipher key on the secure memory space 120 is prevented from being read. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
