摘要 |
An apparatus and method for generating a unique working key variable for controlling the operation of an encryption/decryption device during each user specified time period. The apparatus generates each working key variable by encrypting a user specified value, unique for each specified time period, under control of a fixed key variable stored in the apparatus. After the user specified value has been encrypted, the apparatus utilizes the encrypted (working) key variable to control the encryption/decryption of data during the corresponding user specified time period.
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