| 摘要 |
PROBLEM TO BE SOLVED: To increase encryption strength by preventing an initialization vector from leaking.SOLUTION: An encrypting device, in performing encryption in the CBC mode, performs block-encryption of initialization vector acquisition information to be used for acquiring an initialization vector to be used by a decrypting device for decryption, and generates encrypted text data including an encrypted text block corresponding to a plain text block split from plain text data and an encrypted text block of the initialization vector acquisition information. In decrypting the encrypted text data, the decrypting device acquires the initialization vector on the basis of the initialization vector acquisition information obtained by decrypting the encrypted text block of the initialization vector acquisition information, and performs decryption by utilizing the acquired initialization vector. |
