| 主权项 |
1. A transmission system comprising a first transmission apparatus to encrypt data, and a second transmission apparatus to receive encrypted data from the first transmission apparatus and decrypt the encrypted data,
the first transmission apparatus including: a first head encryption unit configured to encrypt a head block among a plurality of blocks obtained by dividing data to be encrypted, using an encryption initial value; a non-head encryption unit configured to, using an encrypted block among the plurality of blocks, encrypt a block next to the encrypted block; a first transmitter configured to transmit first encrypted data generated by the first head encryption unit and the non-head encryption unit and the encryption initial value to the second transmission apparatus; a first holding unit configured to hold end encrypted data obtained by encrypting an end block among the plurality of blocks by the non-head encryption unit; a second head encryption unit configured to encrypt a head block among a plurality of blocks obtained by dividing data to be encrypted, using the end encrypted data held by the first holding unit; and a second transmitter configured to transmit second encrypted data generated by the second head encryption unit and the non-head encryption unit to the second transmission apparatus, and the second transmission apparatus including: a first decryption unit configured to perform decryption on the first encrypted data using the encryption initial value, the first encrypted data and the encryption initial value being received from the first transmission apparatus; a second holding unit configured to hold the end encrypted data included in the first encrypted data; and a second decryption unit configured to decrypt the second encrypted data received from the first transmission apparatus, using the end encrypted data held by the second holding unit. |
