| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital circuit capable of improving the security by a flexible method without increasing the processing overhead. SOLUTION: This digital circuit having a security mechanism has two types of instruction execution forms. One execution form is carried out by using message authentication technique after performing authentication as to whether or not a program is correct in a reading mode. The other execution form is carried out without authentication even though the other execution form is limited by a form having no security problem. Thus, it is possible to realize a flexible security system that does not have execution overhead effectively. |
