Ic card for encryption or decryption process and encrypted communication system and encrypted communication method using the same

An IC card, used for executing an encryption process or a decryption process using unique encryption key information,

• said IC card comprising:
• a memory;
• a CPU that executes predetermined processes based on data and programs stored in the memory;
• and an I/O unit that performs transaction of information with an exterior;
• a first storage location, a second storage location, and a third storage location being secured inside said memory;
• said programs including a basic program, a key information generating program and an encryption and decryption program;
• said basic program having a function of carrying out a process only once of writing provided data to be written as a fixed code into said first storage location, when a write command with data to be written into said first storage location is provided from the exterior via said I/O unit, and a function of carrying out a process of writing provided data to be written as a variable code into said second storage location, when a write command with data to be written into said second storage location is provided from the exterior via said I/O unit;
• said key information generating program having a function of carrying out a computation process based on a predetermined algorithm using the fixed code stored in said first storage location and the variable code stored in said second storage location to generate encryption key information that is determined uniquely according to said two codes and storing the encryption key information in said third storage location, when a key information generating command is provided from the exterior via said I/O unit;
• and
• said encryption and decryption program having a function of carrying out an encryption process or a decryption process inside the IC card using the encryption key information stored in said third storage location, when a command for an encryption process or a command for a decryption process is provided from the exterior via I/O unit.

An IC card, used for executing an encryption process or a decryption process using unique encryption key information,

• said IC card comprising:
• a memory;
• a CPU that executes predetermined processes based on data and programs stored in the memory;
• and an I/O unit that performs transaction of information with an exterior;
• a first storage location, a second storage location, and a third storage location being secured inside said memory;
• said programs including a basic program, a key information generating program and a key reading program;
• said basic program having a function of carrying out a process only once of writing provided data to be written as a fixed code into said first storage location, when a write command with data to be written into said first storage location is provided from the exterior via said I/O unit, and a function of carrying out a process of writing provided data to be written as a variable code into said second storage location, when a write command with data to be written into said second storage location is provided from the exterior via said 1/0 unit;
• said key information generating program having a function of carrying out a computation process based on a predetermined algorithm using the fixed code stored in said first storage location and the variable code stored in said second storage location to generate encryption key information that is determined uniquely according to said two codes and storing the encryption key information in said third storage location, when a key information generating command is provided from the exterior via said I/O unit;
• and
• said key reading program having a function of reading out the encryption key information stored in said third storage location or a portion of the encryption key information for execution of an encryption process or a decryption process outside the IC card, when a command for an encryption process or a command for a decryption process is provided from the exterior via 1/0 unit.