Information recording medium, recording apparatus, information transmission system, and decryption apparatus

A recording apparatus comprising:

• setting means for setting encrypted key draft information and condition information used upon decryption;
• first generation means for generating encrypted key information on the basis of the encrypted key draft information and the condition information which is not encrypted;
• recording means for recording common key information;
• second generation means for generating key information by decrypting the encrypted key information generated by said first generation means using the common key information recorded in said recording means;
• input means for inputting information to be encrypted;
• third generation means for generating encrypted information by encrypting the information to be encrypted input by said input means using the key information generated by said second generation means;
• and
• recording means for recording the encrypted key information including the condition information generated by said first generation means and the encrypted information generated by said third generation means on an information recording medium in correspondence with each other.

An information transmission system, which comprises a first apparatus having an information recording medium that records encrypted information, and encrypted key information obtained by encrypting key information for decrypting the encrypted information to obtain original information, and a second apparatus which is connected to said first apparatus via a communication line and receives the encrypted information and encrypted key information transmitted from said information recording medium of the first apparatus,

• wherein non-encrypted condition information used upon decrypting the encrypted information is recorded in the encrypted key information recorded on said information recording medium of said first apparatus,
• said first apparatus comprises:
• transmission means for transmitting the encrypted key information including the condition information and the encrypted information recorded on said information recording medium to said second apparatus,
• said second apparatus comprises:
• first output means for outputting the condition information, encrypted key information, and encrypted information received from said first apparatus to a processing medium for performing decryption;
• and
• execution means for executing processing in accordance with decrypted information from said processing medium, and
• said processing medium comprises:
• determination means for determining based on the condition information from said second apparatus if decryption is granted;
• decryption means for, when said determination means determines that decryption is granted, decrypting the encrypted information on the basis of the encrypted key information from said second apparatus;
• and
• second output means for outputting the information decrypted by said decryption means to said second apparatus.

A decipher apparatus that processes encrypted information, and encrypted key information obtained by encrypting key information for decrypting the encrypted information to obtain original information, comprising:

• recording means which records second specific information generated based on first specific information and common key information;
• setting means for setting the first specific information;
• generation means for generating the common key information on the basis of the first specific information set by said setting means and the second specific information recorded on said recording means;
• first decryption means for obtaining key information by decrypting the encrypted key information using the common key information generated by said generation means;
• and
• second decryption means for obtaining information before encryption by decrypting the encrypted information using the key information obtained by said first decryption means.

A decipher apparatus of a portable medium that processes encrypted information, and encrypted key information obtained by encrypting key information for decrypting the encrypted information to obtain original information, comprising:

• an input unit at which first specific information and common key information are input;
• first generation means for generating second specific information on the basis of the first specific information and the common key information input at said input unit;
• recording means for recording the second specific information generated by said first generation means;
• inhibition means for inhibiting input from said input unit after recording on said recording means;
• setting means for setting the first specific information;
• second generation means for generating the common key information on the basis of the first specific information set by said setting means and second specific information recorded on said recording means;
• first decryption means for obtaining key information by decrypting the encrypted key information using the common key information generated by said second generation means;
• and
• second decryption means for obtaining information before encryption by decrypting the encrypted information using the key information obtained by said first decryption means.

A decipher apparatus that processes encrypted information, and encrypted key information including condition information used upon decrypting the encrypted information and obtained by encrypting key information for decrypting the encrypted information to obtain original information, comprising:

• recording means which records second specific information generated based on first specific information and common key information;
• setting means for setting the first specific information;
• generation means for generating the common key information on the basis of the first specific information set by said setting means and the second specific information recorded on said recording means;
• first decryption means for obtaining key information by decrypting the encrypted key information using the common key information generated by said generation means;
• second decryption means for obtaining information before encryption by decrypting the encrypted information using the key information obtained by said first decryption means;
• determination means for determining based on the condition information if decryption is granted;
• and
• control means for controlling execution of decryption by said first and second decryption means on the basis of the determination result of said determination means.