| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit capable of minimizing development man-hours attendant on revision of a secret key and requiring no mask design. SOLUTION: A secret key is encrypted by using a fixed key 101 in advance and an external device 600 stores the encrypted secret key. In the case of encrypting / decrypting data, a selector 104 selects the encrypted secret key encrypted by the fixed key 101 and sets the selected key to an encryption / decryption circuit 105. Then a selector 103 selects the fixed key 101 and the encryption / decryption circuit 105 decrypts the encrypted secret key and stores the secret key to a secret key storage register 102. The selector 103 selects the stored secret key and the selector 104 further selects encrypted data or plain text data to encrypt / decrypt the data. Since the fixed key 101 is used to encrypt an optional secret key in advance to securely set the optional secret key to an LSI in this way, it is not required to store the secret key to a ROM. COPYRIGHT: (C)2004,JPO
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