| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce the amount of use of a RAM, to reduce time for detecting trouble such as falsification, and to write a deciphered and authenticated data block into a nonvolatile memory simultaneously. <P>SOLUTION: In a ciphering device for ciphering a plaintext data to be written into a rewritable nonvolatile memory on a deciphering device side, the input plaintext data is divided into one or more data blocks that become integral multiples of the bank size of the nonvolatile memory, and authentication data is created from the data blocks. Then, ciphertext data is generated after coupling the authentication data with the data blocks. In the deciphering device, the reverse processing is performed to decipher the plaintext data, and the plaintext data is written in the nonvolatile memory. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
