Patent ID: 8571206

Claim:
An information transmitting apparatus that encrypts according to a given encrypting algorithm, and transmits to a destination, transmit data that includes contents for which a transmission instruction has been received, an authentication code that authenticates the contents and a sender of the contents, and padding, the apparatus comprising: a memory; and a processor coupled to the memory, wherein the processor executes a process that includes calculating a size of the padding based on the encrypting algorithm, a size of the authentication code and a size of the contents; calculating a size of the transmit data from the size of the padding, the size of the authentication code, and the size of the contents; generating, using the size of the transmit data, a header that indicates a type of the transmit data and the size of the transmit data; encrypting the transmit data after the generating of the header is completed; and transmitting, to the destination, the header and the encrypted transmit data.