Information transmitting apparatus, information transmitting method, and computer product

An information transmitting method of encrypting according to a given encrypting algorithm, and transmitting 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 method comprising:

• calculating, using a processor, 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 processor and 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.

A non-transitory computer-readable recording medium storing therein an information transmitting program for encrypting according to a given encrypting algorithm, and transmitting to a destination, transmit data that includes contents for which a transmission instruction is received, an authentication code that prevents the contents from being altered and a sender of the contents from being disguised as a different person, and padding, the program causing a computer to execute a process comprising:

• 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.